Literature review to assess bird species connectivity to Special ...

Scottish Natural Heritage 

Commissioned Report No. 390 

Literature review to assess bird 

species connectivity to Special 

Protection Areas

COMMISSIONED REPORT 


Literature review to assess bird species 

connectivity to Special Protection Areas 

For further information on this report please contact: 

Dr Susan Haysom 

Scottish Natural Heritage 

Great Glen House 

INVERNESS 

IV3 8NW 

Telephone: 01463-725000 

E-mail: Susan.Haysom@snh.gov.uk 

This report should be quoted as: 

Pendlebury, C., Zisman, S., Walls, R., Sweeney, J., McLoughlin, E., Robinson, 

C., Turner, L. & Loughrey, J. (2011). Literature review to assess bird species 

connectivity to Special Protection Areas. Scottish Natural Heritage 


This report, or any part of it, should not be reproduced without the permission of Scottish Natural 

Heritage. This permission will not be withheld unreasonably. The views expressed by the author(s) of 

this report should not be taken as the views and policies of Scottish Natural Heritage. 

© Scottish Natural Heritage 2011. 

i

COMMISSIONED REPORT 

Summary 

Literature review to assess bird species connectivity to 

Special Protection Areas 


Contractor: Pendlebury, C., Zisman, S., Walls, R., Sweeney, J., McLoughlin, E., 

Robinson, C., Turner, L. & Loughrey, J. 

Year of publication: 2011 

Background 

The purpose of this literature review is to help to identify where there may be 

‘connectivity’ between qualifying bird species of a Special Protection Area (SPA) and 

the SPA when the birds are recorded outwith its boundary. Stage 3 of the Habitats 

Regulations Appraisal process asks “Is the proposal likely to have a significant effect 

on the site?” This step acts as a screening stage, removing from the Habitats 

Regulations Appraisal plans/projects which clearly have no connectivity to a site’s 

qualifying interests or those where it is very obvious that the conservation objectives 

for the site’s qualifying interests will not be undermined despite a connection. This 

review provides information on dispersal and foraging distances for a range of bird 

species (listed in Table 1) which, as qualifying interests of SPAs, are frequently 

encountered during the consideration of plans and projects. This information should 

help in the identification of potential connectivity. 

Main findings 

The review presents information on foraging distances during breeding and winter 

seasons and distances between alternative nest sites for a range of bird species 

which need to be taken into account when assessing connectivity. The main findings 

are summarised in tables 7 – 9 of the report. 

For further information on this project contact: 

Dr Susan Haysom Tel: 01463 725000 

For further information on the SNH Research & Technical Support Programme contact: 

DSU (Policy & Advice Directorate), Scottish Natural Heritage, Great Glen House, Inverness, IV3 8NW. 

Tel: 01463 725000 or research@snh.gov.uk 

ii

Table of contents 

Page 

1. Introduction ................................................................................................... 1 

1.1 Deriving foraging distance estimates from foraging ranges ............................ 2 

1.2 Analysis of radio-tracking data ........................................................................ 2 

2. Species accounts.......................................................................................... 3 

2.1 Red-throated diver .......................................................................................... 3 

2.2 Black-throated diver ........................................................................................ 5 

2.3 Red kite ........................................................................................................... 6 

2.4 Hen harrier ...................................................................................................... 8 

2.5 Goshawk ....................................................................................................... 11 

2.6 Golden eagle................................................................................................. 16 

2.7 Osprey........................................................................................................... 20 

2.8 Merlin ............................................................................................................ 22 

2.9 Peregrine....................................................................................................... 24 

2.10 White-tailed eagle ......................................................................................... 26 

2.11 Short-eared Owl ............................................................................................ 29 

2.12 Black grouse ................................................................................................. 31 

2.13 Golden plover................................................................................................ 34 

2.14 Greenshank................................................................................................... 37 

2.15 Dunlin ............................................................................................................ 39 

2.16 Curlew ........................................................................................................... 41 

2.17 Whooper swan .............................................................................................. 42 

2.18 Wintering geese ............................................................................................ 43 

2.19 Greylag goose............................................................................................... 43 

2.20 Pink-footed goose ......................................................................................... 43 

2.21 Greenland white-fronted goose..................................................................... 44 

2.22 Barnacle goose ............................................................................................. 44 

3. Summary...................................................................................................... 46 

3.1 Foraging ranges during breeding season ..................................................... 46 

3.2 Foraging ranges during winter season.......................................................... 47 

3.3 Distances between alternative nest sites ...................................................... 47 

4. References................................................................................................... 49 

iii

Tables 

Page 

Table 1 - Species reviewed..........................................................................................2 

Table 2 – Goshawk winter territory estimates............................................................15 

Table 3 - Ages and mean dispersal distances of golden eagles in Great 

Britain from ring recoveries (taken from Grant & McGrady, 1999).............................19 

Table 4 - Short-eared owl territory estimates.............................................................29 

Table 5 - Evidence of male and female home range size..........................................31 

Table 6 - Distance of foraging flocks from Loch of Strathbeg ....................................44 

Table 7 - Summary of foraging distances during breeding season............................46 

Table 8 - Summary of foraging distances during winter season ................................47 

Table 9 - Summary of distances between alternative nest sites................................48 

iv

Acknowledgements 

Rhys Bullman and Andrew Stevenson are thanked for their comments on a previous 

draft. The following people are thanked for provided information on particular 

species: David Anderson (goshawk), Duncan Cameron (red kite), Ken Crane (golden 

eagle), Colin Crooke (golden eagle), Roy Dennis (osprey), Kevin Duffy (red kite), 

Nigel Harding (whooper swan), Dave Lambie (golden eagle), Chris Rowley (hen 

harrier), and Ken Shaw (whooper swan and pink-footed goose). 

v

1. INTRODUCTION 

Proposals for operations or developments affecting Special Protection Areas (SPAs) 

have to be judged on a case-by-case basis using the procedures established through 

the Habitats Directive. These assess whether development proposals are likely to 

have an impact on a designated site. The Conservation (Natural Habitats. &c.) 

Regulations 1994, as amended, set out measures to ensure that the Habitats and 

Birds Directives are implemented in accordance with planning law in the UK. 

SPAs (including potential SPAs) are protected by legal policies placed on competent 

authorities 1 to consider consents or permissions relating to plans or projects that 

could adversely affect the conservation interest of a European designated site. The 

competent authority must establish whether the proposed consent or permission is 

directly connected with, or necessary to, site management for nature conservation. It 

must also decide whether it is likely to have a significant effect on the site either 

individually or in combination with other plans or projects. The authority must take 

account of advice from Scottish Natural Heritage (SNH). 

The purpose of this literature review is to help to identify when there is a connection 

between a proposal and the qualifying interests which may compromise the site. 

Stage 3 of the Habitats Regulations Appraisal process asks “Is the proposal likely to 

have a significant effect on the site?” This step acts as a screening stage, removing 

from the Habitats Regulations Appraisal plans/projects which clearly have no 

connection to a site’s qualifying interests or those where it is very obvious that the 

conservation objectives for the site’s qualifying interests will not be undermined 

despite a connection. This review provides information on dispersal and foraging 

distances for a range of bird species (listed in Table 1) which, as qualifying interests 

of SPAs, are frequently encountered during the consideration of plans and projects. 

This information should help in the identification of potential connections. 

1 This term derives from the Habitats Regulations and relates to the duties which the 

Regulations impose on public bodies and individuals. Regulation 6(1) defines competent 

authorities as "any Minister, government department, public or statutory undertaker, public 

body of any description or person holding a public office". In the context of a plan or project, 

the competent authority is the authority with the power or duty to determine whether or not the 

proposal can proceed. 

1

Table 1 - Species reviewed 

Common name 

Red-throated diver 

Black-throated diver 

Red kite 

Hen harrier 

Goshawk 

Golden Eagle 

Osprey 

Merlin 

Peregrine falcon 

White-tailed eagle 

Short-eared owl 

Black grouse 

Golden plover 

Greenshank 

Dunlin 

Curlew 

Whooper swan 

Greylag goose 

Pink-footed goose 

Greenland white-fronted goose 

Barnacle goose 

Latin name 

Gavia stellata 

Gavia arctica 

Milvus milvus 

Circus cyaneus 

Accipiter gentilis 

Aquila chrysaetos 

Pandion haliaetus 

Falco columbarius 

Falco peregrinus 

Haliaeetus albicilla 

Asio flammeus 

Tetrao tetrix 

Pluvialis apricaria 

Tringa nebularia 

Calidris alpina 

Numenius arquata 

Cygnus cygnus 

Anser anser 

Anser brachyrhynchus 

Anser albifrons albifrons 

Branta leucopsis 

1.1 Deriving foraging distance estimates from foraging ranges 

Many of the published studies reviewed for this document provide estimates of the 

species’ foraging range in terms of the area they regularly forage within. In this 

document, estimates of foraging distances have been estimated based on calculating 

the radius of a circle of the area given as the foraging range. These estimates 

assume that the foraging ranges are circular in shape, which may not be the case in 

situations where conditions such as habitat, topography, or food supply, are 

heterogeneous. These estimates can be useful, however, where no information on 

foraging distance is provided. 

1.2 Analysis of radio-tracking data 

Published studies that have used radio-tracking to estimate a species’ foraging area 

can vary in the analytical method used to derive the estimates. The two main 

methods that were used in the literature reviewed were ‘minimum convex polygons’ 

and ‘kernel analysis’. The ‘minimum convex polygon’ method derives an area that 

completely encloses all recorded locations by connecting the outer locations in such 

a way that all internal angles are less than 180°. Kernel analysis involves producing 

areas around a point location that contain a specific likelihood of the animal’s 

presence. 

2

2. SPECIES ACCOUNTS 

2.1 Red-throated diver 

2.1.1 Foraging 

Maximum foraging range 

Red-throated divers usually fly to marine waters to feed. When breeding far inland, 

they may occasionally feed on the nearest large body of fresh water (Cramp, 1977; 

Bright et al., 2006). 

A Scotland-wide study of breeding distribution in relation to the availability of fishing 

waters found foraging trips to be limited to within 8km of the nest site, with the 

exception of one site (Rannoch Moor) (Merrie, 1978). 

A study on Lewis recorded outbound flights ranging up to 7.2km (mean: 3.7km; n=97) 

from the breeding loch (Lewis Windfarm Environmental Statement, Appendix 12). 

However, given the limitations in the survey method (fixed vantage points at breeding 

lochs) this is likely to be an underestimate of the maximum range. Additional surveys 

of pairs breeding on plateau moorland on Lewis recorded flight lengths of at least 

11km, with maxima of up to 13.5km (Addendum to Lewis Windfarm Environmental 

Statement, Appendix 12). 

A study in Arctic Canada found that pairs nesting in excess of 9km from coastal 

feeding areas were associated with reduced nesting success (Picman, 1993). 

Non-breeding birds, and failed pairs, can congregate and show a large amount of 

activity around lochans away from breeding areas. A study near Bettyhill found these 

lochs may be 1km to 2km away from the Caithness and Sutherland SPA (Bettyhill 

Environmental Statement). 

Likely foraging destination 

Feeding has rarely been recorded at Scottish breeding waters and occurs almost 

exclusively at sea or in estuaries (Cramp 1977; Bright et al., 2006; Okill, 2007). 

Likely route of foraging flights 

In Shetland, many flights between the breeding loch and the sea are not direct, but 

follow circuitous routes while over land. Jackson & Beasley (2006) considered that 

such indirect routes were likely to be the most energetically economic for a number of 

reasons: 

 

 

they minimise the need for the birds to gain altitude to fly over high ground, by 

following river valleys and passing through gaps between hills; 

they avoid kleptoparasitism, i.e. stealing of resources such as food, nesting 

material, etc, by skuas; and 

wide, circling flights over the sea or adjacent land allow birds returning to 

elevated nest sites to gain height gradually. 

Divers’ characteristic long curving flights starting into the wind are a consequence of 

the anatomical constraints of being heavy birds with very high wing loading and very 

short tails (R Furness pers. comm. 2010). 

3

Non-breeding birds, following less predictable flight routes, were responsible for 

approximately one third of flights recorded in the Shetland study (Jackson & Beasley, 

2006). These birds ranged widely and unpredictably over a number of lochs. 

A study on Lewis reported that foraging flights between the breeding loch and coastal 

feeding sites were generally direct, except immediately after taking off from the 

breeding loch on outbound flights, or prior to landing after incoming flights (Lewis 

Windfarm Environmental Statement, Appendix 12). Close to breeding lochs, both 

inbound and outward flights often included circling while the birds orientated towards 

a landing spot or the sea. Approximately 80% of circling/orientating flight occurred 

within 400m of the breeding loch while 90% occurred within 650m of it. Once outside 

of the ‘orientation zone’, foraging flights were nearly always along the shortest route 

to the nearest coast. After accounting for one case where a second, almost 

equidistant coast was preferred, the direct line to the nearest coast explained 97% of 

the variance in the median bearing at all sites. 

2.1.2 Nesting 

Alternative nest sites 

Alternative nest sites can be used between breeding seasons, especially where there 

is an abundance of available lochans for the number of breeding pairs. On Lewis, 

distances of approximately 1km between nest sites used in consecutive years are not 

unusual (Andrew Stevenson pers. comm.). 

4

2.2 Black-throated diver 



There is little quantitative information available on foraging ranges of black-throated 

diver. In Britain, breeders commonly fly between breeding lochs and coastal sites 

that may be “several kilometres away” (Jackson, 2003). In taiga of Northern Russia, 

where fishing was poor, birds were reported to travel to feeding lakes 5–10km from 

the nest site (Cramp, 1977). Pairs breeding on North Lewis have been recording 

flying approximately 7-8km whilst brood-rearing (Andrew Stevenson pers. comm.). 

Studies in North-west Scotland and the Western Isles have found foraging range to 

be associated with chick age (Jackson, 2003). Foraging excursions that occur after 

the chicks were four days old (the post-brooding phase) tended to be to more distant 

feeding sites, but typically still within 2km of the brood (Jackson, 2003). 

Likely foraging destination 

Feeding mainly occurs on the breeding loch, occasionally on surrounding lochs and 

exceptionally at nearby coastal sites among Scottish breeders, (Jackson, 2003). 

Likely route of foraging flights 

No specific information has been found on the likely routes of foraging flights. 

Observations suggest that flight routes and heights are similar to those of redthroated 

divers (Andrew Stevenson pers. comm.). 

2.2.2 Nesting 

No additional information pertinent to connectivity, was found. 

2.2.3 Post-breeding roosts 

Roosts have been recorded between July and September involving non-breeding 

and post-breeding birds. Such a roost was recorded on North Uist holding a 

maximum of 15 birds, which is likely to include birds breeding at least 4-5km away 

(Fuller, 2003). 

5

2.3 Red kite 


Core foraging range during the breeding season 

Adult red kites rarely undertake long-distance movements, tending to remain close to 

the nest site throughout the year. The species does not defend a home range but 

defends a nest site against other kites, raptors and corvids (Corvus sp.) (Carter, 

2001; Davis et al., 2001). 

Estimates of the foraging range from the nest site include: within 4km (English 

Nature, 2002), within 3km (Carter, 2001; Davis et al., 2001) and within 2km (Ward, 

1996). 

Maximum foraging range during the breeding season 

Records of red kites around the Braes of Doune Windfarm have shown that adults 

can travel over 5km from their territories during the breeding season (Kevin Duffy 

pers. comm.). Other studies have estimated that foraging occurs up to 6km during 

the breeding season (Carter, 2001; Davis et al., 2001). 

Winter foraging range 

Radio-tracking work carried out by the RSPB found sub-adult red kites regularly 

ranging within 10km from their winter roosts, with maximum distances of 20km (Kevin 

Duffy pers. comm.). Other accounts have estimated that red kites normally forage 

within 4km of their roost site during winter, utilising a maximum area of up to 2000- 

3000ha (English Nature, 2002). Studies of Welsh birds have found individuals 

travelling 10km in a single day (Cramp & Simmons, 1980). Studies in Germany 

found red kites foraging up to 10km from the roost site (Davis & Davis, 1981). 

A study in Germany found smaller winter home range sizes (based on minimum 

convex polygons): 800ha and 620ha (equivalent to foraging distances of 

approximately 1.6 and 1.4km) for a single male in two successive years; and 710ha 

(equivalent to a foraging distance of approximately 1.5km) for a single female during 

one year (Nachtigall et al., 2003). Home ranges were found to increase as winter 

proceeded and prey availability reduced. 

2.3.2 Nesting 

Nest site fidelity 

Red kites tend to nest in the same restricted territories year after year, with each 

territory holding several nests which have been built or refurbished in different years 

(Newton et al., 1994; English Nature, 2002). Alternative nest sites are therefore likely 

to be within 1km from each other. 

2.3.3 Display flights 

High circling displays, involving one or both birds of a pair, occur over the nesting 

area, usually early in the day (Cramp & Simmons, 1980). The bird(s) will rise on an 

up-current with wings extended, and then continue soaring. The majority of displays 

take place below 150m, with some occurring up to approximately 220m (Duncan 

Cameron pers. comm.). 

6

High flying, up to 1000m, can also occur throughout the year with several birds up at 

once (Cramp & Simmons, 1980; Duncan Cameron pers. comm.). This usually takes 

place in fine weather and either early or late in the day. The majority of flights during 

the breeding season will be at heights of less than 100m, but this is dependent on a 

number of factors including weather and the rate of disturbance (Duncan Cameron 

pers. comm.). 

2.3.4 Competitive behaviour 

Edge of territory interactions with conspecifics 

Territorial disputes between red kites are common (Carter, 2001; Davis et al., 2001). 

Despite this, a study in England found that pairs will breed within a few hundred 

metres of their nearest neighbours. They found seven pairs breeding within an area 

of about 400ha (Carter, 1997). 

2.3.5 Habitat use 

Likely habitat use 

Red kites are generally found below 600m a.s.l. (Minns & Gilbert, 2001). They 

require mature woodland for breeding and roosting, with extensive open low ground, 

moorland areas and marginal agricultural habitats for foraging. Arable areas, as well 

as land with mixed livestock and rough grazing, are particularly favoured, while 

farmyards and roads provide sources of prey and carrion (Orr-Ewing, 2007). Open 

stands of coniferous and broadleaved woodland are used for nesting and communal 

roosting in winter, with Scots pine being the most commonly recorded species used 

(Carter & Grice, 2000). Nachtigall’s study in Germany reported red kites avoiding 

areas of deep vegetation during the breeding season, presumably because prey is 

less easy to find (Nachtigall, 1999). 

2.3.6 Winter behaviour 

Winter dispersal 

During winter, most adult birds remain close to their home range, where they will 

often roost together (Davis et al., 2001). Some birds may move to a local or regional 

communal roost. Red kites re-introduced in Perthshire have been recorded roosting 

communally during the winter in numbers between 51 and 63 (Duncan Cameron 

pers. comm.). 

About 20% of first-year Scottish red kites from the two established reintroduction 

sites disperse from early August to early November (Davis et al., 2001). These birds 

tend to move in a south-westerly direction and some have reached Cornwall and 

Ireland. A greater proportion of females than males tend to disperse. 

7

2.4 Hen harrier 


Foraging range 

The foraging range of hen harrier is poorly understood due to a lack of quantitative 

data (Bright et al., 2006). Estimates for Scottish birds are 3-4km for males and 2- 

3km for females, with males consistently ranging further than females (Watson, 

1977). 

Based on data from Angus/Aberdeenshire, Scotland (Picozzi, 1978), it was estimated 

that foraging ranges can be greater than 1500ha in area, which would be equivalent 

to a foraging distance of approximately 2.2km. 

Data on range sizes are available from radio-tracking studies at Langholm, Orkney 

and Galloway (Arroyo et al., 2005, 2006). Average estimates of the ranging area 

used 90% of the time for male hen harriers varied between 650 and 1180ha 

(equivalent to foraging distances of approximately 1.4km and 1.9km), depending on 

the method of analysis. Equivalent figures for females ranged between 290 and 

350ha (equivalent to foraging distances of approximately 1.0km and 1.1km). For 

each method of analysis, female home ranges were almost half of those of males. In 

shape, female home ranges were roughly circular around the nest sites, whereas 

those of males were not necessarily so, and a preferred foraging direction was 

apparent in at least three of the monitored males (though there is no information on 

the factors determining this direction). 

In terms of distances travelled from the nest by radio-tagged birds in the above study 

(Arroyo et al., 2005, 2006), 93% of female fixes were within 2km of the nest and 70% 

were within 1km of the nest. In contrast, 35% of male fixes were further than 2km 

from the nest, and the maximum distance from the nest at which a male was 

recorded was 8.5km. 

Foraging distances of up to 10km have been recorded in Uist, for males breeding in 

bog areas and foraging on the coast to prey on migrant and breeding waders 

(Andrew Stevenson pers. comm.). A female has been recorded in Uist carrying prey 

approximately 8km from a nest. 

2.4.2 Prediction models 

Madders (2003) provides a model that aims to predict the relative use made of 

different parts of local ranges occupied by hen harrier during the breeding season. 

The model proposes to use existing data sources and takes account of nest 

proximity, vegetation cover and structure, and the distribution of linear habitat 

features. The model predicts harrier ranging behaviour using a standard index based 

on nest distance. This avoids the need to make assumptions about an individual’s 

foraging range or ‘core area’. 

2.4.3 Nesting 


In Scotland, hen harriers usually nest in the same area in successive years, with the 

median distance moved between sites from year to year being 0.71km (Etheridge et 

al., 1997). The largest movement, which was by a female, was 188km. 

Picozzi (1984a, b) found that, in Orkney, female harriers that moved into a new 

territory moved further following breeding failure than after successful breeding. 

Etheridge et al. (1997) also found a small, but non-significant, difference in distance 

8

moved in successive years between successful female breeders (0.63km) and 

unsuccessful females (0.81km). 


The first tentative display flights begin in late March, with full displays by late April 

(Watson, 1977). Male displays generally ceases about the time the eggs are laid, 

whilst females display late into the fledging period. 

The male’s ‘sky-dancing’ display consists of a steep climb of approximately 30m, 

followed by a roll and dive (Cramp & Simmons, 1980). The performance is generally 

at heights between 30 and 150m, and may be repeated several times; 105 

successive dives have been recorded during a single display. Display flights can 

also involve high circling, at up to 500m from the ground (Cramp & Simmons, 1980). 

Males will display over several possible nesting stations, travelling from hill to hill and 

rising above each in turn. 

Females often also display, although their flights take a ‘switch-backing’ course 

rather than the steep ascents and descents of the male. Female displays, therefore, 

tend to take place at lower heights than those of males. 

The majority of display flights are expected to be around the nest site (Hardey et al., 

2006). Males displaying near the Strathy Forest have been recorded as displaying 

up to 1km from the nest site (RPS data). 



Male hen harriers actively defend a nest territory of approximately 600m in diameter 

(Watson, 1977). Foraging ranges of males overlap extensively, whilst ranges of 

females do so to a lesser extent (Arroyo et al., 2005, 2006). Hen harrier intra-specific 

aggression peaks early in the season, is mainly intra-sexual, and increases with the 

number of neighbours (Garcia & Arroyo, 2002). 



In Scotland, the majority of pairs nest in heather moorland, with ling heather (Calluna 

vulgaris) typically being dominant in the immediate vicinity. Species such as bracken 

(Pteridium aquilinum), bog myrtle (Myrica gale), rushes (Juncus spp.), willow (Salix 

spp.) and purple moor grass (Molinia caerulea) may also be present along with open 

and closed forestry plantation (Potts, 1998; Hardey et al., 2006). 

The importance of heather in Scottish populations has been demonstrated by 

Redpath et al. (1998). They found that 94% of hen harrier nests were located in 

rank, but not degenerate heather, with an average height of 46cm. They also found 

that the nests tended to be nearer streams than would be expected by chance, and 

that there was an indication of preference for north-west facing slopes. Hen harriers 

prefer foraging in young first rotation coniferous forests and select heathland and 

heterogeneous grassland habitats over closed canopy woodland (Madders, 2000). 

Foraging hen harriers tend to avoid afforested habitats with lots of foliage greater 

than 5m tall, homogeneous grassland areas, and areas with a large cover of bracken 

(Madders, 2000). 

9



During the winter, hen harriers occur in open country throughout Britain, with lowlying 

coastal areas in south and east England and south-west Scotland being 

particularly favoured (Clarke & Watson, 1990). In Scotland, females tend to winter 

on higher ground (above 200m a.s.l.) than males (below 100m a.s.l.) (Clarke & 

Watson, 1990). 

The proportion of birds dispersing over distances greater than 25km is greater 

amongst northern birds, such as those from the North and East Highlands 

(approximately 90%), than amongst southern birds such as the West Highlands 

(approximately 80%) and Southwest Uplands (approximately 60%) (Etheridge & 

Summers, 2006). Sightings of tagged birds from Scotland suggest a migration route 

through the Southern Uplands and into England (Etheridge & Summers, 2006). 

Hen harriers almost invariably roost among rank ground vegetation, in a variety of 

open habitats. They are sociable raptors, roosting in groups of usually less than 20, 

but can also roost individually (Clarke & Watson, 1990). 

A study of two communal roosts in south-west Scotland found the majority of hunting 

birds within 6km of one roost, and between 8 and 12km (and up to approximately 

16km) from the other roost (Watson, 1977). The majority of foraging from winter 

roosts is thought to be within approximately 10km (Chris Rowley pers. comm.). 

10

2.5 Goshawk 


Core foraging range 

Adult goshawks are sedentary in Britain and Ireland (Petty, 2002, 2007b). The size 

of goshawk home-ranges, and nest density, vary considerably with the availability of 

suitable prey (Petty, 2007a) and woodland (Kenward, 1982, 2006; Hardey et al., 

2006; Petty, 2007b). Woodland edge is a very important resource for this ambush 

predator; individual goshawks with the greatest access to woodland edge 

consequently have the smallest home ranges (Kenward, 1982). 

Goshawks defend only the nesting territory against other goshawks (Cramp & 

Simmons, 1980), and hunt within large overlapping home ranges (Kenward, 2006; 

Hardey et al., 2006). In suitable woodland habitat in the UK and abroad, nest sites 

are regularly spaced (UK: Petty, 1989; Arizona, United States: Reich et al,. 2004). 

Nearest neighbour distances for nest locations in woodland blocks in lowland Britain 

vary between 1.0km and 3.7km (Hardey et al., 2006). 

Radio-tagged goshawks studied during autumn in Sweden (Kenward, 1977) had 

widely overlapping home ranges. From 14 ranges defined, the two smallest (both 

about 700ha; equivalent to a foraging distance of approximately 1.5km) belonged to 

adults, and the two largest (4600 and 4900ha; equivalent to foraging distances of 

approximately 3.8km and 3.9km, respectively) belonged to juveniles. However, the 

ranges of juveniles were large partly because these birds occasionally flew up to 

10km outside their regular areas. Such flights involved soaring, and may have 

served for exploration. 

Goshawk show wide variability in ‘area per territory’. In the UK these vary between 

620 (Marquiss et al., 2003) and 2500ha (Petty, 2006 in Petty, 2007b), with a similar 

pattern across Europe. The situation is also similar in North America, but ‘areas per 

territory’ of up to 9000ha have been recorded (Wagenknecht et al., 1998). Since 

birds tend to hunt within overlapping home ranges, these areas cannot be used to 

estimate foraging distances. Based on observations of breeding goshawk in 

Scotland, however, most hunting is believed to take place within 10km of the nest 

site (David Anderson pers. comm.). 

2.5.2 Buffers around the nest site 

Goshawk adults use an area 100-200m from the nest site intensively for perching, 

plucking and feeding (Kenward, 2006). Petty (1998) prescribes 400m, or an area of 

50ha, as an appropriate buffer around goshawk nest sites to prevent disturbance. 

This is based on goshawk territories from north-east Scotland and the Scottish 

Borders. The site-specific characteristics of the nest area, and surrounding 

woodland size and structure, should be used to determine the exact extent of the 

buffer required around an active nest site. 

Desimone & Hays (2004) propose a method for the management of the breeding 

home range of the Northern goshawk, including nest areas, nest area clusters, postfledging 

areas and a foraging area. The 2442ha total home range includes the 

foraging area (2200ha), the post-fledging area (170ha) and nest areas (72ha). This 

method of management for the goshawk home range (during the breeding season) 

would use a buffer radius of 2.79km. 

Penteriani & Faivre (2001) found no significant difference in the productivity of 

goshawk pairs reproducing in unlogged vs. logged stands. They observed that 

87.5% of goshawk pairs nesting in logged stands moved away only when the original 

11

stand structure was altered by more than 30%, and then only to the nearest 

neighbouring mature stand (maximum distance: approximately 1.5km). 

2.5.3 Maximum foraging range 

The maximum foraging range for goshawk can vary considerably, dependent on the 

nest location, prey availability and woodland habitat (Newton, 1979; Kenward, 2006). 

From observations of breeding goshawk in Scotland, the maximum distance over 

which foraging has been recorded is 18km from the nest site (David Anderson, pers. 

comm.). This is based on marked prey items, i.e. ringed wild nestlings which would 

still have been either on the nest or within the natal territory where they were ringed, 

being found at the nest. 

Individuals may change their hunting areas during the course of a breeding cycle 

(Newton, 1979). This can be in response to seasonal changes in prey distribution or 

to changes in their prey needs, and partly because they are more able to range long 

distances in the late season since they no longer need to guard the nesting territory 

or the young so closely. Home ranges often change size and shape during the 

season, and get larger as the season progresses. More specifically, home range 

sizes depend on habitat and local food availability, on the age and competence of the 

birds concerned, and on their immediate food-needs, which are greatest when there 

are large young to feed. 

2.5.4 Nesting 


Goshawks are site faithful and maintain breeding territories from year to year. 

Historic nesting records in the Scottish Borders confirm that goshawks can use the 

same territories in commercial forestry for at least 10 years (Petty, 1989). Goshawk 

territories tend to have at least two alternative nests, on average 200-300m apart. 

Change of use is every other year on average, but continuous use of single nests for 

up to 17 years has been recorded (Kenward, 2006). 

Alternative nesting ranges used by the same pair can be as far as 2.5km apart 

(Hardey et al., 2006). In North-east Scotland, fieldworkers surveying goshawks first 

check all known nesting ranges, and then widen the search around those that are 

apparently unoccupied until an occupied nesting range is found. 


Reich et al., (2004) described the spatial distribution of active nests (i.e. nests in 

which eggs are laid) within a US goshawk population and modelled the interaction 

between nest locations and forest structure. This then allows a model to predict the 

location of active nests in a given year. Reich et al. (2004) used a GIS model to 

describe the spatial dependency of goshawk: 

 

 

among nest locations influenced by territoriality; and 

between nest locations and the environment. 

12

Nest locations were regularly distributed at a minimum distance of 1.6km between 

active nests; however as the spatial scale increased (i.e. as distance between the 

nests increased), the degree of regularity decreased. 


High-circling displays by single birds or a pair can be seen throughout the year but 

are more intense over the nest area in March and early April by both male and 

female. 

Several types of display flight have been described for the goshawk, as follows: 

 

sky-diving or sky-dance display involving high circling, flapping and soaring in 

tight spirals; undulating and slow flapping flight (gradually losing height); 

sometimes further circling to regain height; and plunging from a height of up 

to several hundred metres into the nesting wood with wings held towards the 

side (Hardey et al., 2006); 

a display involving an undulating flight, like a woodpigeon but with even 

sharper descents and ascents ‘as if rebounding from an invisible elastic 

surface’ with wings almost closed (Joubert & Margerit, 1986 in Kenward, 

2006); 

zigzag chasing flights between the trees (Schnure, 1963 in Kenward, 2006). 

These flights may represent misplaced aggression as opposed to normal 

display, although they have been reported as being more prevalent than 

display flights above the canopy; and 

female goshawk displays occurring above the woodland canopy on sunny, 

relatively windless days. During these, the female holds the long, main tail 

feathers together and the snow-white undertail coverts spread apart so wide 

that the goshawk appears to have a short, broad tail. The display involves 

slow deliberate wing-beats, with the wings held stiff and straight (Demandt, 

1927, 1933 in Kenward, 2006). 

Both topographic and thermal soaring are used by goshawk, the former along ridges 

or where updrafts occur at the windward edges of dense woodland (Kenward, 2006). 

82% of 71 observed soaring flights were in the middle of the day, from late morning 

to early afternoon. Soaring occurs in the warmest parts of the day, when thermals 

are present, and also tends to occur in the warmest parts of the year. Goshawks 

sometimes soar high, up to 300-400m, to be easily noticed (Kenward, 2006). The 

travelling speed of a goshawk is estimated to be 15ms -1 (Rutz, 2006). 



Goshawk home ranges, during both the breeding season and winter, overlap 

considerably (Hardey et al., 2006; Kenward, 2006), but the immediate nest site is 

defended (Hardey et al., 2006). Although juvenile goshawks share foraging areas 

extensively, core areas of territorial adults do seem to be more discrete (Kenward, 

2006), indicating a greater degree of separation during the breeding season. Male 

goshawks do not move far to breed, the majority probably having home-ranges 

created between other breeding pairs rather than becoming ‘floaters’ in the 

population. 

Goshawk nests tend to be regularly spaced (Rutz & Bijlsma, 2006), as they are for 

many raptors (Newton, 1979). Territory spacing is most regular at a small scale, 

13

whereas over large areas the nests tend to be clumped, presumably in the best 

habitat (Reich et al., 2004). Regular spacing indicates that social behaviour, in the 

form of territoriality, limits the number of goshawks that breed in an area, with nonbreeders 

constrained to areas less suitable for breeding. 



Habitat type and structure is important to goshawks. It supports prey populations, 

provides structure and concealment when foraging (e.g. for perches) and nesting, 

and provides cover from predators (Kenward, 2006). Goshawk were historically 

confined to mature forests, but now also nest in smaller woods, younger stands 

(Forsman, 1999), and urban areas (Rutz, 2006). Goshawks are usually found close 

to woodlands (Kenward, 2006; Hardey et al., 2006) but also hunt in open areas, 

especially outside of the breeding season. 

Goshawk are pause-travel hunters, using a technique of short-stay perched hunting 

(SSPH) as an alternative to soaring and low prospecting flights (Kenward, 2006). 

SSPH dominates hunting behaviour in winter and continuous forest, but soaring 

becomes more frequent in warm weather and can dominate hunting of urban 

goshawks during breeding (Rutz, 2006). 

Goshawks favour woodland edge zones. Perch locations of radio-tagged goshawks 

in Sweden indicated 73-76% of perch locations were within 200m of a woodland 

edge. Radio-tracking studies in Britain and Sweden have shown most kills are made 

in close proximity to edge habitat (within 100m, one flight distance) when foraging for 

lagomorphs, pigeons and pheasants in fragmented woodland (Kenward, 2006). 

Goshawks have also been recorded favouring large blocks of mature forest for 

mammal prey, such as squirrels, in the Scottish Borders (Petty et al., 2003) and 

Swedish taiga (Kenward, 2006). 

Nesting ranges, which are generally less than 5ha in extent (Petty, 1996), are 

normally found in large blocks of mature forest. They can occur in woods smaller 

than 3ha (Marquiss & Newton, 1982) but usually only where there is a lack of 

extensive woodland elsewhere. 



Juveniles disperse from their natal areas in late summer (June to August). The only 

data on natal dispersal distances come from the Scottish Borders, where males 

moved significantly shorter distances (median: 14.7km) than females (median: 

31.7km) (Petty & Anderson, 1996). The pattern of breeding range increase is 

therefore one of creeping expansion (Lensink, 1997). The greatest natal dispersal 

distance recorded, 70km was by a female reared in the Peebles area that settled to 

breed in Kielder Forest, Northumberland. 

Table 2 sets out winter foraging ranges for goshawk. These are believed to extend 

up to 2000-4000ha (equivalent to foraging distances of 2.5km to 3.6km) for Western 

Europe between 55-58° latitude, including Scotland (Kenward, 2006). Studies of 

winter foraging distances from roost sites are limited within the scientific literature. At 

higher elevations in the Borders, adult males appear to be the only sex/age class that 

over-winter, suggesting that some females move away from their home ranges after 

breeding (Petty, 2007b). 

14

Ringing recoveries of an adult female provided insight into the range of movements 

by some goshawks. Ringed as a nestling near Eskdalemuir, the bird bred for a 

number of years in Galloway (both Dumfries & Galloway) 46km from its natal area, 

and was finally recovered dead during the winter in Keswick, Cumbria (Petty, 2007b). 

Table 2 – Goshawk winter territory estimates 

Location Year Area per territory (ha) Reference 

Rural 

Oxfordshire, 

UK 

1973 - 

1975 

380-1360ha; equivalent to a foraging 

distance of 1.1-2.1km. 

Kenward 

(1982) 

Pheasant release area: 2000ha; 

equivalent to a foraging distance of 

1.1-2.1km. 

Central 

Sweden 

1976 - 

1978 

Mainly wild pheasant area: 2600ha; 


2.9km. 

Kenward 

(1982) 

Only wild pheasants: 5400ha; 


4.1km. 

15

2.6 Golden eagle 



Golden eagles in Scotland maintain large, mostly exclusive home ranges (Watson 

1997; Haworth et al., 2006). These are occupied throughout the year and defended 

against intruding eagles, mainly by undulating flight display (Watson, 1997; Crane & 

Nellist, 1999). 

Core foraging range was defined by McGrady et al. (1997) to be “the area 

encompassing 50% of the ranging locations of eagles”. In this study mean ‘core 

area’ of radio-tagged birds was 500ha (range: 190 to 720ha). This is equivalent to a 

mean foraging distance of 1.3km (range: 0.8km to 1.5km). Haworth et al. (2006) 

estimated mean core ranging areas (based on the area encompassing 50% of 

ranging locations) on mainland Argyll to be 504ha (range: 310 to 810ha; equivalent to 

a mean foraging distance of 1.3km; range: 1.0km to 1.6km), and on Mull to be 210ha 

(range: 140 to 280ha; equivalent to a mean foraging distance of 0.8km; range: 0.7km 

to 0.9km). 

Analysis of radio-tracking data, before and after the construction of a wind farm in 

Argyll, showed a pair of resident eagles had a core range (based on the area 

encompassing 50% of ranging locations) that covered a combined area of 2900ha 

(Walker et al. 2005). This is equivalent to a mean foraging distance of 3.0km. 


Maximum foraging ranges tend to show differences spatially and temporally, 

probably reflecting prey abundance (Haworth et al., 2006). Studies in the UK have 

recorded resident eagles moving up to 9km from their territory centre (McGrady et 

al., 1997). These individuals had a mean total territory size of 6830ha (range: 

2600ha to 12850ha). Haworth et al. (2006) estimated 100% kernel range areas (the 

area encompassing all ranging locations) for 11 study ranges in western Scotland to 

be between 860ha and 6690ha (equivalent to mean foraging distances between 

1.7ha and 4.6km). Walker et al. (2005) estimated foraging range of an Argyll pair 

(based on minimum convex polygons) as 3290ha (equivalent to a mean foraging 

distance of 3.2km), with 95% of eagle activity within 2050ha (equivalent to a mean 

foraging distance of 2.6km). 

2.6.2 Nesting 


Adult golden eagles in Scotland tend to be sedentary birds that have a number of 

alternative eyries (Brown, 1976). They usually have two to three nests, but 

occasionally up to 13 (Watson, 1997). The 1982 eagle survey estimated a mean of 

3.4 nest sites per pair (Watson, 1997). In western Scotland the mean number of 

alternative nest sites is approximately 4.5 per pair (range: 2 to 10; Watson, 1997). 

Pairs with several different eyries will usually have one or two that are favoured. 

Watson (1997) notes that ‘movers’ (using four or five sites in a ten year period) had a 

significantly higher incidence of disturbance than ‘stayers’ (usually one favoured nest 

for six out of ten years). Watson (1997) also suggests that use of alternative nests 

could be to reinforce ownership rights or to reduce the effect of parasite infestations. 

The distance between alternative nest sites in different years will depend on 

population density and home range size, and can be up to 6km (Watson & Rothery, 

16

1986). A pair on a home range in the western Highlands, which has up to 12 

recorded eyries within 3kms of each other, has been recorded moving 1.25km in 

consecutive years to alternative nest sites (Enda McLoughlin, unpublished data). A 

pair in the Cairngorms, which has been recorded using four different eyries, has been 

recorded moving to alternative nest sites between 1.5km and 2.5km apart in 

consecutive years (Dave Lambie pers. comm.). On Skye, alternative nest sites tend 

to be no more than 2km apart in consecutive years (Ken Crane pers. comm.). In 

areas such as West Sutherland, alternative nest sites may be further apart (up to 

6km) due to low prey density (Colin Crooke pers. comm.). 


Display flights are a function of territoriality which increases in frequency from 

autumn and peaks at the end of the pre-laying period in early spring (Watson, 1997). 

The purpose of display flights are a form of passive aggression towards neighbouring 

breeders and intruding non-breeders, the latter especially in early winter. 

During a long-term study of golden eagles on Skye, males were recorded displaying 

throughout their territory, with display flights on the same territory occurring up to 

6km apart (Ken Crane pers. comm.). Collopy & Edwards (1985, in Watson, 1997) 

recorded golden eagles in Idaho displaying near boundaries, within view of other 

territorial golden eagles, and displaying simultaneously with neighbouring territorial 

pairs. 

Most displays fall roughly into three simple patterns (Crane & Nellist, 1999): 

1) ‘on the spot’: forward display into a strong head wind, with the forward 

motion being counteracted by the reversing force of the wind; 

2) ‘travelling’: forward undulating display flight continued over a relatively 

straight large distance; and 

3) ‘in a circle’: undulating display flight undertaken in a large circle. 



Territory boundaries are marked, as explained above, by display. A winter study by 

Crane & Nellist (1999) found display activity by a young resident pair attempting to 

expand their territory was double that of the combined displays of two older, 

neighbouring pairs. These two well established pairs had little or no aggressive 

interactions and their borders seemed undisputed. Aggression towards neighbouring 

resident breeders is generally rare (but can exist in high density populations), whilst 

aggression towards non-breeders is common (Haller, 1982 and Bergo, 1987a, both 

in Watson, 1997; Crane & Nellist, 1999). Intrusions into occupied territories are rare, 

and birds will generally stop at the boundary of their territory, but intrusions do 

occasionally occur (Ken Crane pers. comm.). However, intrusions into currently 

unoccupied territories are more frequent (Ken Crane pers. comm.). 

These interactions usually involve chases and dives in which the intruder defends 

itself by rolling over and presenting its talons, sometimes going through a 360° roll 

(Crane & Nellist, 1999). 

17



Golden eagles are typically found in mountainous, coastal and upland regions 

(Cramp & Simmons, 1983), with open areas of short or sparse vegetation, especially 

slopes and plateaus and good visibility for hunting (McGrady et al., 1997). 

Additionally, particular geographical features, such as south-west facing slopes that 

provide good uplift in prevailing weather conditions, are important for efficient soaring 

and hunting. 

The chosen habitat must provide secure alternative nest sites with easy open access 

(Cramp & Simmons, 1983). Golden eagles typically nest on cliffs, between 150m 

and 450m a.s.l. (Watson & Dennis, 1992). 5% of Scottish breeders nest in trees 

(McGrady et al., 1997). 

McGrady et al. (1997) recorded habitat preferences. These were (most preferred 

first): montane; heather; coarse grassland; bracken; smooth grassland with scrub; 

bog; broadleaved forest; pre-thicket forest/low scrub; post-thicket forest; improved 

pasture; water; anthropogenic smooth grassland without scrub; salt marsh; wetlands; 

and cliff. 

Golden eagles tend to avoid closed canopy forest and inland water (Watson, 1997) 

although Crane & Nellist (1999) suggest that sea surrounding a headland eyrie can 

be used for observational and patrol flights. In situations where pairs are breeding on 

islands with no ground predators, foraging can occur over a wider range of habitat 

types, including at low elevations (Andrew Stevenson pers. comm.). 


Current models that predict habitat use by golden eagles are the RIN model of 

McGrady et al. (1997, 2002), which was refined by McLeod et al. (2003) to form the 

PAT (Predicting Aquila Territory) model. 

In areas where there is little or no high-quality observational data on golden home 

ranges, the use of PAT modelling has proven useful for predicting golden eagle 

ranging behaviour (Whitfield et al., 2001; McLeod et al., 2003). The ‘PAT’ model 

brings together the known locations of eagle territory centres, digital elevation and 

habitat cover data in a GIS environment to predict the ranging of the birds within their 

core area (within 2-3 km of the nest). Predictions are generated from these data 

along with the species’ known habitat preferences at better-studied sites. 

The main applications of the model are in predicting eagle responses to 

developments and mitigation. Information on habitat management and other 

mitigation, or the size and location of developments, can usefully predict how ranging 

behaviour is likely to be influenced. While PAT modelling is less accurate than high 

quality field observations, it produces more reliable response predictions than those 

based simply on distance from the nest. 



Adult golden eagles hold home ranges that encompass both their hunting and 

nesting territory and are occupied all year round (Hardey et al., 2006). Young golden 

eagles leave their natal territory between 60 and 80 days after fledging (Watson, 

1997). Ring recoveries give some indication of mean dispersal distances (Table 3). 

18

Grant & McGrady (1999) followed two juveniles for periods from one month to 

twenty-one months. One bird moved varying distances over a 15 month period, the 

greatest being 75km. Another made similar long distance movements over a 10 

month period, with 35km being the greatest distance recorded from its natal home 

range. 

Details of juvenile ranging behaviour are emerging from a study of a satellite-tracked 

juvenile by the Highland Foundation for Wildlife in partnership with the Cairngorms 

National Park Authority, Scottish Natural Heritage and Glenfeshie Estate (Highland 

Foundation for Wildlife 2008). The juvenile female ranged up to 80km from its birth 

place by mid-April in its first winter, and was recorded up to 140km away in its first 

spring (Highland Foundation for Wildlife 2008). 

A study of juvenile dispersal in south west Spain, using satellite tags on thirteen 

individuals, recorded mean areas of 371300 ± 258600ha for males and 1065200 ± 

745100ha for females (Soutullo et al., 2006). This is equivalent to distances of 

34.4km for males and 58.2km for females. 

Table 3 - Ages and mean dispersal distances of golden eagles in Great Britain 

from ring recoveries (taken from Grant & McGrady, 1999) 

Age (calendar years) No of recoveries Mean and range of 

dispersal distance (km) 

1-2 24 67.6 (11-161) 

3 4 44.0 (27-77) 

4 4 22 (7-47) 

7 1 11 

19

2.7 Osprey 



Foraging locations are usually within 10km of nesting locations, with some males 

recorded as making regular foraging flights of approximately 20km (Hardey et al., 

2006; Roy Dennis pers. comm.). One satellite-tracked individual has been recorded 

to occasionally hunt at 28km from the nest (Roy Dennis pers. comm.). 

2.7.2 Nesting 


The same nest is regularly used from year to year, with fidelity to the site thought to 

be strong (Cramp & Simmons 1980). If eggs are lost from a nest, for example 

through egg collecting, ospreys would tend to build a ‘frustration eyrie’ within 2km of 

the original nest, which may be used in the following year (Hardey et al., 2006). 

Breeding-age birds may settle close to or far from natal sites (Cramp & Simmons, 

1980). From colour-ringing sightings, eight of 26 males and two of 28 females were 

found to breed within 10km of their natal sites (Dennis, 2002). Maximum recorded 

displacement, based on ringing, is 950km (Cramp & Simmons, 1980). 


Male display flights consist of ‘sky-dancing’ in the vicinity of the nest (Cramp & 

Simmons, 1980). Other aerial activity in the nesting area may include: high circling 

flights by the pair; chasing of other ospreys; and undulating sky-dance song flights by 

the male carrying fish or nest-material (Cramp & Simmons, 1980). 

The undulating sky-dance song flight, which may begin and end at the nest, involves 

the male usually carrying nest material or fish (Cramp & Simmons, 1980). The bird 

rises increasingly steeply with rapid and pronounced wing-beats to approximately 

300m or more. He hovers a moment with tail fanned and legs dangling – displaying 

what he carries in his feet (hovering-flight) - then dives with wings flexed. This is 

followed by rising steeply again, repeating the performance one or more times. The 

descent may be for only 10m, or the male can lose most of the height gained in steps 

of 20-40m with intermediate stops. 

Sky-dancing males are most frequent near the nest-site before incubation. This is 

most often performed on clear, sunny days and seems to mark out nesting territory 

as well as to advertise the nest site to the female (Cramp & Simmons, 1980). 



Ospreys do not defend a home range, such as foraging locations (Hardey et al., 

2006). They will, however, defend a nesting territory against ospreys of the same 

sex (Hardey et al., 2006). 

20



The locations of breeding sites require an ample supply of medium-sized fish which 

are caught near the surface of clear, unpolluted water (Cramp & Simmons, 1980). 

Lochs used for foraging are generally shallow and eutrophic (nutrient-rich) or 

mesotrophic (medium levels of nutrients), but not normally oligotrophic (nutrient-poor) 

since these do not tend to support sufficient amounts of fish (Hardey et al., 2006). 

In Scotland, ospreys are tree-nesters, with Scots pine selected most frequently, and 

exotic conifers and deciduous trees also used (Dennis, 1987). 



The main wintering grounds of European ospreys are in sub-Saharan Africa (Cramp 

& Simmons, 1980). 

21

2.8 Merlin 



Studies of merlin in the UK, in south-east Grampian and Wales, have found 

maximum foraging ranges from the nest of 3.4km and 4km, respectively (Rebecca et 

al., 1990). Studies on the Western Isles, Orkney and Caithness/Sutherland have 

found that breeding birds can regularly hunt 4-5km from the nest (Andrew Stevenson 

pers. comm.). 

Studies in North America found similar ranging distances: means of 3-5km, and a 

maximum of 8km, were recorded in Alaska (Schempf, 1989 in Rebecca, et al. 1990); 

and means of 6.3km and 6.6km for resident males and females, respectively, nesting 

in Saskatoon, Canada (Sodhi & Oliphant, 1992). 

2.8.2 Nesting 


Nest site fidelity varies between adult females (Ellis & Okill, 1990). Nesting areas 

have been recorded being used in consecutive years (Cramp & Simmons, 1980; Parr 

1991) with one study recording two patches of heather being used over 12 and 19 

consecutive years (Rebecca et al., 1992). Nestlings can also show strong natal nest 

site fidelity (Meek, 1988; Wright, 2003) 

Alternative nest sites within a territory are generally a few hundred metres apart, but 

have been recorded at 300m (Hardey et al., 2006), 500m (Bibby, 1987) and up to 

1.5km (Jackson & Beasley, 2006). 


Display flights are relatively inconspicuous and occur at the start of the breeding 

cycle on hot, sunny days (Cramp & Simmons, 1980). The male and female circle 

over the nest site with shivering wings, often 50-100m high, with the male changing 

to slow wing beats for 10 second periods and giving ‘chip’ or ‘chok’ calls (Cramp & 

Simmons, 1980). The female gives ‘kee kee kee’ calls or a whistling call similar to a 

curlew. Display flights are generally within 100m of nest sites. 

Whilst prospecting alternative nest sites, flights between sites will generally be low. 



Merlin do not hold exclusive territories for hunting during the breeding season, 

defending only the territory immediately around the nest site (Hardey et al., 2006). 

Birds nesting within 2km of each other show mean overlaps in hunting range of 0.1 to 

11.8% and 27.9 to 32.9% for males and females, respectively, depending on several 

factors including the stage of the breeding season (Sodhi & Oliphant, 1992). A radiotracking 

study in Grampian showed that at least two pairs shared hunting ranges 

(Rebecca et al., 1990). 

There is little evidence of home ranges being defended in winter (Hardey et al., 2006) 

and it is likely that, in some areas with a high population density, winter home ranges 

will overlap (Warkentin & Oliphant, 1990). 

22



Potential merlin nesting habitat includes: grass and heather moorland, bracken, 

young plantation, mature plantation edges and rides (within 100m of plantation), 

open areas within afforested blocks, and open birch, pine and alder woods (Rebecca 

& Bainbridge, 1998). Of these, the dominant habitat types used for nesting are 

heather moorland, grass moorland, trees in grassland, and conifer plantation. Where 

merlin nest in trees, old carrion crow (Corvus corone), hooded crow (C. cornix), 

magpie (Pica pica) or buzzard (Buteo buteo) nests are used. Carrion crow nests are 

used most often. Preferred heather depths vary, with nests having been recorded in 

heather ranging in height from 30-70cm (Wright, 1997), 7-50cm (Meek, 1988), and 

10-35cm (Ellis & Okill, 1990). 

Habitat used for hunting during the breeding season is mainly open country, including 

moorland. In winter, merlin favour arable farmland, rough pasture, estuaries, sand 

dune systems and low lying heaths (Hardey et al., 2006) 



In the UK, many merlin disperse to lower altitudes and coastal areas after breeding. 

Of ringed birds, data show that 71% of first year birds, and 78% of adult birds, 

disperse within 100km of breeding sites (Heavisides, 2002). Scottish birds 

dispersing further afield move into England and Ireland, with small numbers having 

been recovered in Europe, from south-east Spain to northern Germany (Heavisides, 

2002). All the birds recovered in Europe were recovered during the winter period 

(October-April) and consisted of both first-year and adult birds (Heavisides, 2002). In 

Shetland, some birds do over-winter in the islands, although there are very few 

sightings of adult males (Ellis & Okill, 1990). 

A study of urban merlin during the winter in Saskatchewan, Canada, found mean 

hunting ranges of 1960ha (equivalent to a mean foraging distance of 2.5km) for 

adults and 1790ha (equivalent to a mean foraging distance of 2.4km) for first year 

birds (Warkentin & Oliphant, 1990). A study in west Galloway found a small winter 

range for one adult female that was observed occupying a range of just 2km from a 

communal roost (Dickson, 1989). 

23

2.9 Peregrine 



Peregrines do not hold exclusive home ranges, with areas used for hunting 

overlapping with neighbouring pairs (Newton, 1979; Ratcliffe, 1993). They defend a 

nesting territory, however, with average nearest-neighbour distances varying 

between 2.1km and 9km in different regions of Britain (Ratcliffe, 1993). 

It is believed that peregrines take 70% of their prey from within 2km of the nest (Weir, 

1977, 1978), suggesting that the core foraging range will be approximately 2km. 

2.9.2 Maximum foraging range 

Maximum foraging ranges tend to be variable between different nest sites and 

regions (Ratcliffe, 1993). Studies in Britain have recorded maximum foraging 

distances of 6km (Weir, 1977, 1978), 11-12km (on Uist; Andrew Stevenson pers. 

comm.), 13km (Mead, 1969), 15km (Glutz Von Blotzheim, 1971 in Bright et al., 

2006), 16km (Ratcliffe, 1993), and 18km (Mearns, 1985). Larger foraging distances 

have been documented in Colorado, USA, with a radio-tracking study finding flights 

extending to 20-43km from the eyrie (Enderson & Craig, 1997). 

2.9.3 Nesting 


Pairs tend to return to the same nest site between years (Mearns & Newton, 1984; 

Ratcliffe, 1993). Alternative nest ledges and cliffs are regularly used. Studies have 

found mean distances between alternative nesting locations to be 2.7km in the 

Scottish Southern Uplands (n=28 territories), 2.4km in northern England (n=40 

territories), and 2.1km in north Wales (n=24 territories) (Ratcliffe, 1993). Maximum 

distances between alternative nesting locations tend to be between 5 and 6.5km. 


Display flights generally occur in the nesting territory and immediate vicinity during 

the breeding season (Cramp & Simmons, 1980). These include high-circling, 

undulating flights, figure-of-eight flights, and fight-play. They can involve either one 

or both birds of the pair (Cramp & Simmons, 1980). The heights at which display 

flights take place are generally up to 200m, and they can take place up to 1km from 

the nest site. 



Territorial attacks tend to occur only within approximately 1.6km from the eyrie 

(Ratcliffe, 1993). 

24



Peregrines require extensive open terrain for hunting, and are often attracted to river 

valleys, lochs, and lakes (Cramp & Simmons, 1980; Ratcliffe, 1993). 



If prey items remain numerous during the winter period, peregrines will remain in the 

vicinity of their breeding territory (Ratcliffe, 1993). This tends to be the case in most 

regions south of the Scottish Highlands where peregrines are relatively sedentary. In 

areas where prey items are less numerous, and during hard weather, they will 

disperse to lowland areas (Ratcliffe, 1993). This tends to be the case within the 

Highlands, where peregrines are generally more mobile. 

25

2.10 White-tailed eagle 



Territory ranges are highly variable between populations and are dependent upon 

suitable breeding habitat and prey availability. In coastal areas of Norway where 

prey is readily available, territories are constricted, with only a small area directly 

around the nesting site being defended. In this situation foraging areas are used by 

more than one pair (Bright et al., 2006). In favourable habitats in mainland Europe, 

neighbouring pairs may nest as close as 1-2km apart (Cramp & Simmons, 1980). On 

Mull, with the highest average population density in Scotland, the mean distance 

between neighbouring pairs nest is 8.6km (range: 3.2-14km; Hardey et al., 2006). 

A study of a population of white-tailed eagles in Russia recorded birds hunting a 

mean area of 1310ha (Masterov, 2003 in Bright et al., 2006). It was observed that 

most foraging activity took place within 5km of the nest site but some pairs flew up to 

13km from the nest to forage. 

A study of a white-tailed eagle population in Schleswig-Holstein, Germany found that 

the 16 breeding pairs in 1995 had a mean territory size of 6200ha (Struwe-Juhl, 

1996a & b). This is equivalent to a mean foraging distance of 4.4km per pair. 

2.10.2 Nesting 


Pairs tend to be fairly site faithful, and adults are resident in their territory throughout 

the majority of their range (Halley, 1998). Throughout their range there is evidence 

suggesting some individual territories have been occupied for many years. For 

example, one territory on Mull has been occupied since 1986. Studies in Finland and 

Sweden have shown that some territories have been in use for several decades, or 

even centuries, and in Iceland one territory has been consistently occupied for the 

last 150 years (Bright et al., 2006). 

White-tailed eagles may have between one and 11 nest sites within their nesting 

range, generally ranging from 2m to 3km apart (mean: 480m; Cramp & Simmons, 

1980). On Rum, six out of 10 pairs studied had one or two alternative eyries, with the 

distance between alternate nesting sites often being within 2km (Love, 1988). On 

Mull, alternative nest sites have been recorded several kilometres apart, whilst on 

Skye they have been found up to 12km apart (Bright et al., 2006). Larger distances 

between alternative nest sites tend to be more prevalent amongst inexperienced 

birds (Hardey et al., 2006). Studies of a population of white-tailed eagles in Lithuania 

have found that pairs tend to nest within 1.3km from the previous year’s nest (Jusys 

& Mecionis, 1992). 


Display flights generally occur in the nesting territory and immediate vicinity, as early 

as early/mid December in long-standing resident pairs. The display flights involve 

either one or both birds of the pair circling high over the nesting area. Mutual circling 

can occur as far as 3km from the eyrie, but is generally only over a limited area, at 

heights below 200m (Cramp & Simmons, 1980). 

During mutual circling, more elaborate displays can ensue (Cramp & Simmons, 

1980). This can involve the pair flying between 1 and 6m apart and moving in 

concentric circles. The upper bird will either pounce towards the lower bird, which 

26

will subsequently role away, or tilt over in partial flight-roll and fall headlong on to the 

other bird, which in turn rolls so that both birds fall into a spin. In the latter case the 

birds will separate and perform a type of sky dance, sweeping in opposing curves, 

rising and falling in gentle undulations. Brief talon touching sometimes occurs during 

flight play, and mutual high circling results in a duet of loud calling. 



White-tailed eagles do defend their territories but are not as aggressive as golden 

eagles. Defence of territories tends to vary between individuals, with certain pairs 

being particularly tolerant of intruders whilst others are more aggressive (Hardey et 

al., 2006). In Norway, white-tailed eagle territories overlap and pairs are known to 

nest within as little as 1 or 2km of each other, and in some cases as close as 200- 

500m where prey is in abundance (Bright et al., 2006). In Scotland, pairs of whitetailed 

eagle on the Isle of Skye have been observed to breed within 1km of their 

neighbouring pair (Halley, 1998). 

White-tailed eagles are tolerant of golden eagles within their territory. Halley (1998) 

observed both white-tailed eagles and golden eagles on the coasts of Norway and 

Scotland frequently nesting in close proximity to each other, with their home ranges 

greatly overlapping. 



Prior to extinction, the Scottish population of white-tailed eagles occurred in both 

inland and coastal habitats. They bred in lowland woodlands near estuaries, 

marshes and lochs, but during their decline in the 19 th century the population became 

restricted to coastal areas (Love, 2007). Since their successful reintroduction in 

Scotland, many sea cliff sites used prior to extinction are being used once again, with 

some birds also nesting in woodlands or new plantations close to the coast (Love, 

2007). 

In general, white-tailed eagles are associated with aquatic environments, i.e. sea 

coasts, lake shores, rivers, islands and wetlands, where fish and other aquatic prey 

are plentiful (Cramp & Simmons, 1980). White-tailed eagles mainly feed on seabirds 

and fish, as well as carrion, but are not specialised feeders so can turn from one food 

supply to another. The species therefore has a broad tolerance of habitat 

requirements (Waterston, 1964). The species occurs in a variety of habitats 

throughout the world, such as desert steppe, Mediterranean, and boreal zones into 

taiga and tundra where they arrive and breed during the brief Arctic summer (Cramp 

& Simmons, 1980). White-tailed eagles do tend to avoid mountainous, waterless or 

treeless terrain as well as extensive forest tracts. They also rarely use habitats 

beyond the littoral zone, although in Norway they do occur on rocky, sparselypopulated 

islands (Cramp & Simmons, 1980). 



Throughout the majority of their range, particularly in the western palearctic, adult 

white-tailed eagles are sedentary and remain in their home ranges all year round, 

(Hardey et al., 2006). 

27

Juvenile and immature white-tailed eagles disperse from their natal homes during the 

winter. In Scotland, juveniles disperse during their first winter but have a tendency 

towards natal philopatry in following years (Hardey et al., 2006). 

There are a few white-tailed eagle populations, irrespective of age, which are 

completely migratory due to food and latitudinal effects. For example in Russia, birds 

which breed in areas greater than 60˚N in latitude are completely migratory because 

freshwater bodies freeze over in the winter thus prey becomes unavailable (Cramp & 

Simmons, 1980). 

Immature birds will also gather in winter in areas where food is locally abundant. In 

mainland Europe, up to 30 to 40 birds at one roosting site have been recorded 

(Cramp & Simmons, 1980). Some young birds will also disperse large distances 

during the winter, with birds from Norway having been observed in Iraq, Israel, north 

Mediterranean, and North Africa (Cramp & Simmons, 1980). 

28

2.11 Short-eared Owl 



The foraging range of short-eared owls during the breeding season, and the degree 

to which this will overlap with neighbouring pairs, is poorly-known. Information that 

does exist suggests ranges vary between areas and years, depending on the 

abundance of prey. When prey items, such as voles, are abundant, short-eared owls 

will tend to defend exclusive home ranges (Hardey et al., 2006). When food items 

are more limited, and when the pair is feeding young, hunting outwith this defended 

area will be more frequent (Cramp, 1985). 

Several studies have estimated territory size, producing widely-varying means of 

between 40ha and 350ha (Table 4). On this basis, mean foraging distances vary 

between 0.4km and 1.7km. However, these estimates do not take into account any 

foraging that may occur outwith the territory. 

Based on these studies, the core foraging range for short-eared owl is likely to be 

within 2km of the nest site. However, longer foraging distances will take place. For 

example, a bird on North Uist was recorded flying 4 to 5km with food to its nest 

(Andrew Stevenson pers. comm.). 

Table 4 - Short-eared owl territory estimates 

Location 

Year of 

study 

Area per 

territory 

(ha) 

Mean distance to 

territory boundary 

(km) 

Reference 

Roxburgh 1934 230 to 300 0.9 to 1.0 Goddard 1935 

Stirlingshire 1954 40 0.4 Lockie 1955 

Wales 

Dumfries 

Finland 

1971- 

1984 

1976- 

1978 

1977- 

1987 

875 1.7 

Roberts & Bowman 

1986 

62 to 112 0.4 to 0.6 Village 1987 

96 0.6 

Korpimäki & Nordahl 

1991 

Galloway 1991 60 0.4 Shaw 1995 

Islay 

1985- 

2004 

350 1.1 

M. Ogilvie pers 

comm., per 

Calladine et al. 2005 


No information on nesting, pertinent to connectivity, was found. 


During display flight, the male typically climbs quite rapidly in fairly tight circles, with 

characteristic ‘wing clapping’, followed by a near-vertical stoop in rocking flight 

29

(Cramp, 1985). The heights at which display flights take place are generally between 

50m and 200m, and generally occur within 300 and 400m from the nest site (Andrew 

Stevenson pers. comm.). 



Territories are defended during the breeding season, mainly by the male (Cramp, 

1985). During the breeding season, males will vigorously respond to trespassing 

owls (Mikkola, 1983). 



Short-eared owls specialise in quartering moorland, preying on small mammals and 

passerines on, or close to, ground level (Mikkola, 1983). In the breeding season, 

extensive areas of open land are required with an abundance of small mammals 

(Cramp, 1985). Favoured habitats include areas of heather moorland, grass 

moorland (where not over-grazed), young conifer plantations, and some other rough 

grassland (Calladine et al., 2005). 

The majority of hunting short-eared owls adopt a coursing (alternate flapping and 

gliding) flight technique (Mikkola, 1983). These coursing flights are usually made 

between 0.3m and 2m above the vegetation, and rarely exceed 3m. A second 

hunting technique frequently adopted, similar to that of kestrels (Falco tinnunculus), 

involves hovering, with descent towards the prey on wings raised in a dihedral 

(Mikkola, 1983). 



For nestlings ringed at the nest, mean dispersal distances are 9km (n=13) within the 

second month, 61km (n=8) within the third month, 228km (n=5) within four months, 

418km (n=5) within five months, and 490km (n=6) within six months (Glue, 2002). 

30

2.12 Black grouse 


Home range sizes 

Evidence from radio-tracking studies have revealed home ranges of black grouse 

adults to be between 250ha and 700ha, equating to mean foraging distances of up to 

1.5km around leks (Table 5). 

Male home ranges tend to be larger than those of females. Brood home ranges are 

also small, generally under 50ha (Starling, 1990) equivalent to a distance of less than 

400m, with a typical range between 10ha and 30ha (Warren & Baines, 2004) 

equivalent to distances between 180m and 300m, both based on work in the 

Pennines. 

In good, continuous habitat, Warren & Baines (2004) suggest leks are approximately 

2km apart. Most birds attending a lek are therefore generally found within 1km. 

Table 5 - Evidence of male and female home range size 

Location 

North-east 

Scotland 

Scotland 

Scotland 

Scotland 

(moorland) 

Scotland 

(woodland) 

Wales 

(conifer 

plantation) 

Wales 

Lekking male home 

range 

500ha (equivalent to 

range of 1.3km) 

300-690ha; mean: 460 ± 



360 ± 180ha (equivalent to 


N/A 

N/A 

325 ± 71ha (equivalent to 


N/A 

Female home range 

N/A 

Reference 

Johnstone 

(1969) 

N/A Robel (1969) 

N/A Picozzi (1986) 

90 ± 40ha (equivalent 

to range of 0.5km) 

50 ± 30ha (equivalent 

to range of 0.4km) 

N/A 



Picozzi (1986) 

Picozzi (1986) 

Cayford 

(1990) 

Cayford 

Hope 

(1989) 

& 

Jones 


No information pertinent to connectivity, was found. 



31







2.12.7 Dispersal 

Female dispersal distances 

Within the UK, black grouse are essentially sedentary (Toms, 2002). Dispersal is 

primarily confined to first-year hens, with adults of both sexes and first-year cocks 

showing high site fidelity (Warren & Baines, 2002; Caizergues & Ellison, 2002). 

The majority of hens disperse in their first winter to settle amongst other lekking 

groups. Radio-tracking studies, in the French Alps (Caizergues & Ellison, 2002) and 

in the north Pennines (Warren & Baines, 2002) show a marked gender contrast in 

post-fledging dispersal. In the former study, 81% of the females left the 840ha 

survey area to nest 5-29km from their site of capture. In the latter study none of the 

eight first-year hens remained within the study site, with distance travelled ranging 

between 4.5km and 19.0km (mean: 9.3km) from their natal area (Calladine, 2002). 

As genetic studies in Finland confirm the high level of male philopatry to their natal 

areas, the conclusion is that the long-term survival of leks relies on immigration of 

hens from surrounding areas. 

This suggests that a development which inhibits dispersal may contribute to lek 

isolation. This is particularly true where leks are further apart. This loss of 

connectivity was associated with reduced males in attendance and declining 

populations in one study of conifer plantations in Argyll (Haysom, 2001). 

In order to avoid such isolation and declines, Caizergues & Ellison (2002) suggest 

the mean dispersal distance (4km in the Alps) should be used to ensure connectivity 

between lekking groups is maintained. In the North Pennines, the mean natal 

dispersal distance was 9km (Warren & Baines, 2002), suggesting a slightly more 

dispersed lek pattern is sustainable. 

Potential physical barriers to dispersal in the UK possibly include some of the higher 

mountains and water, the latter especially for island or peninsular populations 

(Calladine, 2002). 

2.12.8 Male dispersal distances 

Males attend established leks through the year, except when moulting. Home ranges 

of males attending these leks overlap considerably (Cayford & Hope Jones, 1989) 

and are discreet from males attending adjacent leks. 

Where leks are established, the majority of cocks remain close to their natal sites. 

The survivors ultimately recruit into these sites. In the north Pennines study by 

Warren & Baines (2002), all 11 of the first-year cocks remained within 1km of their 

natal site. Interestingly, however, small numbers of males have been recorded 

32

making longer movements (5 to 10km) from their natal area during their first year, but 

these are less common (Grant, 2007). The work by Caizergues & Ellison (2002) 

revealed only 9% of males had emigrated from the 836ha study area between the 

1990 to 1998 research period. In combination, this suggests that a small proportion 

of first-year males may disperse more widely. 

Leks comprising single birds are more mobile and ephemeral, and may be used for 

just one or two years compared to the regular use of traditional leks (Cayford, 1993). 

The implications are that in areas with large numbers of single-bird leks (e.g. Cowal, 

Argyll), male black grouse movements over greater distances may be more common. 

2.12.9 Seasonal movements 

The main seasonal movements of black grouse arise from natal dispersal, of which 

Caizergues & Ellison (2002) identified two discreet phases; one in autumn (October) 

and the other in spring (mid-April to early May). There are periods of reduced 

mobility between these phases. The study also showed that mean distance travelled 

by females exceeded that of males in autumn but not in spring. These findings tally 

with the dispersal patterns identified by Warren & Baines (2002). From a sample of 

48 radio-tagged poults they found distinct dispersal periods in late autumn (mean: 

10.3km) and again in early spring (mean: 5.8km). 

Apart from natal dispersal, both males and females remain in the same general 

locality throughout the year and rarely move more than a few kilometres from the lek 

they attend in spring (Warren & Baines, 2004). 

Winter home ranges of full-grown birds are relatively small and sometimes distinct 

from areas used at other times of the year, with birds congregating on particularly 

favoured areas (Baines et al., 2002; Calladine, 2002). Examples of favoured winter 

habitats are patches of birch and willow, tall vegetation where grazing is restricted, 

vestigial areas of ericaceous vegetation, and herb-rich meadows (Willebrand, 1988; 

Baines, 1994; Starling-Westerberg, 2001; Baines et al., 2002). In their study, Picozzi 

& Catt (1988) identified the greatest use of moorland and rough grassland to be from 

the spring to the late summer or early autumn, whilst most use woodland use was 

generally during winter. 

Ringing data are extremely limited. All 13 recoveries in Scotland have been of 

Scottish-ringed birds, with 10 controlled within 9km of the ringing site and three within 

10-99km (Grant 2007). 

2.12.10 Post-breeding chick dispersal 

As reported above, brood home ranges are small and can be under 50ha (Starling, 

1990) equivalent to a distance of less than 400m. However, they are more typically 

between 10ha and 30ha (Warren & Baines, 2004) equivalent to distances between 

180 and 300m. Dispersal by first-year birds is mainly confined to hens, with a mean 

autumn dispersal of 10.3km from the natal site to the first breeding location, and early 

spring movements of 5.8km (Warren & Baines, 2002). 

33

2.13 Golden plover 



O’Connell et al. (1996, in Byrkjedal & Thompson, 1998) used radio-tracking to 

measure ‘home ranges’ of golden plover in Sutherland. These had a mean area of 

106 ± 92ha and a range of 14ha to 393ha. The core range of off-duty birds 2 was 

between 10m and 2.3km from nest sites (mean 480 ± 31m; excluding long-distance 

foraging flights). 

A radio-tracking study during the post-hatching phase used minimum convex 

polygons to estimate mean ranging area for three male golden plovers at a proposed 

wind farm site in the Highlands (Gordonbush Wind Farm Environmental Statement, 

2006). Measurements taken between 8 th June and 7 th July 2004 showed ranges of 

110 ± 19ha. 




Display flights have a sexual and territorial function, and are nearly always performed 

by the males (Cramp & Simmons, 1983). They occur at various heights, with 

documented estimates of 15-100m (Byrkjedal & Thompson, 1998) and 10 - 300m 

and sometimes higher (Cramp & Simmons 1983). The duration of circling flights is 

usually less than ten minutes but can be up to twenty (Byrkjedal & Thompson, 1998). 

Few data are available on display flight range. However, display flights are centred 

on the potential territory. Once established, the male demarcates the territory by low 

flight (at approximately 20m) roughly following the boundary (Cramp & Simmons, 

1983), so breeding density and nearest neighbour distance could be used as a rough 

calculation for estimating display flight range. Ratcliffe (1976) provides mean 

distances between nests for different density situations: less than 250m at very high 

densities (>10 pairs km -2 ); 450 - 850m at moderate densities (1.5 to 4 pairs km -2 ); 

and greater than 1650m at very low densities (0.5 pairs km -2 ). However, in the early 

stages of territoriality display, paths can cross, ‘home ranges’ can overlap and once 

territoriality settles, neighbouring males may display together (Byrkjedal & 

Thompson, 1998). Data should, therefore, be used with some caution. 


Competitor interaction behaviour 

Birds begin to show aggressive behaviour within spring passage flocks (Cramp & 

Simmons, 1983) and some may start song flights. On reaching breeding grounds, 

flocks quickly break up, usually within a week of the first birds arriving, and disperse 

(Byrkjedal & Thompson, 1998). Males become more aggressive and defend 

territories against intrusions from both sexes, as well as some other wader species. 

Song flight appears to be the main constituent of territorial defence (Byrkjedal & 

2 Both parents share in the incubation of eggs and care of the young (taking them to feeding 

areas, brooding and protecting them from predators). The term ‘off-duty’ refers to the period 

when the adult is not incubating eggs or caring for young. 

34

Thompson, 1998). Other interactions with conspecifics on territories include songduels, 

aggressive posturing, and charging (Cramp & Simmons, 1983). 


Chick habitat choice 

The South Pennines study found that golden plover chick home ranges included a 

greater proportion of cotton grass and bare peat than was available across the study 

area as a whole (Pearce-Higgins & Yalden, 2004). The habitat choices of chicks also 

shifted slightly with age, with younger chicks tending to use cotton grass habitats 

more, and older chicks tending to make more use of crowberry and bilberry habitats 

(Pearce-Higgins & Yalden, 2004). 

In the Durham study, chicks were found to select marshes, grassland and 

Eriophorum vaginatum mire (Whittingham et al., 2001). Rank areas of heather were 

avoided. 


Winter movements 

Golden plovers aggregate during the winter, mainly in coastal regions in Scotland 

(Thompson, D.B.A. 2007). When severe frost and snow cover conditions persist, 

large-scale movements to milder areas, such as south-west England, can occur 

(Fuller & Lloyd, 1981). British wintering birds, in severe cold spells, may also fly to 

Ireland or France (Kirby & Lack, 1993). 


Chick dispersal 

Golden plover chicks can leave the nest when just a day old. A study in the South 

Pennines found that chicks, prior to fledging at around 37 days, occupied mean 

home ranges of 40ha (range: 18.3 to 86.2ha). This average home range size is 

equivalent to a distance of 350m (range: 240 to 520m), though some individuals have 

been recorded occasionally moving up to 1km per day (Pearce-Higgins & Yalden, 

2004). 

A study in Durham followed radio-tagged chicks until they were 16 days old 

(Whittingham et al., 2001). Mean chick foraging range sizes (based on minimum 

convex polygons) were estimated for two sites: 3.41 ± 0.71ha at Chapell Fell; and 

4.61 ± 1.60ha at Widdybank Fell (equivalent to distances of 100m and 120m, 

respectively). It was also found that broods were able to move large distances, e.g. 

700m in 24 hours, after disturbance by humans. 

The Sutherland study found that birds moved progressively further away from the 

nest site: 300 ± 100m from the nest in the first ten days after hatching; and up to 450 

± 240m during days 21-30 after hatching (O’Connell et al., 1996 in Byrkjedal & 

Thompson, 1998). The furthest distance moved by a brood was just less than 1km. 

35

2.13.8 Flight range 

Off-duty flight range 

Mean distance for foraging flights in the Sutherland study, to enclosed fields, was 

2.69 ± 0.26km (range: 0.36 to 10.7km; O’Connell et al., 1996 in Byrkjedal & 

Thompson, 1998). 

A study of golden plover in the South Pennines determined most daytime flights of 

adults (off-duty females) to be 6.6 to 7.2km (maximum: 8.2km) from the nest 

(Pearce-Higgins & Yalden, 2003). 

A study in Durham found that during the incubation period adults flew to enclosed 

fields 1.1 – 3.7km from the nest site (Whittingham et al., 2000). 

2.13.9 Nocturnal flight range 

The majority of nocturnal off-duty flights are by males. In the South Pennines study, 

most of these birds were recorded moving distances of 2.4 to 2.7km (maximum: 

4.2km) from the nest site (Pearce-Higgins & Yalden, 2003). 

36

2.14 Greenshank 



Foraging is reported to be within 1.5km of the nest, with birds occasionally foraging 

up to between 2.5km (Nethersole-Thompson & Nethersole-Thompson, 1979) and 

3.0km (Cramp & Simmons, 1983) from the nest. 


No information pertinent to connectivity was found. 


Display flight range 

Display flights occur most frequently during the early part of the breeding season, up 

to pair-formation. The displays involve the male flying to a height of 60m, 

occasionally up to 300m, before dropping down (Cramp & Simmons, 1983). Most 

display activity occurs between 03:00h and 07:00h. 



A male on territory will approach, usually by flight, any conspecific bird in or near the 

mating area (Cramp & Simmons, 1983). If the other bird remains, the male will 

perform a display on the ground, and the event can culminate in a ‘leap-frogging’ 

flight where each bird jumps alternately at one another. Chasing can also occur, for 

up to 800m. 



Greenshanks breed in sub-montane, boggy habitat, mostly between 210m and 550m 

a.s.l., but also down to sea-level in the north of Scotland (Ratcliffe, 1979; Cramp & 




Outside the breeding season, Scottish greenshanks are believed to winter mainly in 

the Mediterranean or Africa, with some remaining in the British Isles (Thompson, 

2002). Numbers wintering in Scotland, mainly in coastal areas, have ranged 

between 50 and 100 in the last 10 years (Thompson, P.S. 2007). 

37



Broods have been recorded as walking 365-730m from the nest site during the first 

few weeks after hatching (Nethersole-Thompson & Nethersole-Thompson, 1979). 

Chick-rearing will take place within 1.5km of the nest site (Cramp & Simmons, 1983). 

38

2.15 Dunlin 



A study on the Western Isles found that adults generally feed within 500m, and 

occasionally up to 1km, from the nest during incubation and brood-rearing (Jackson, 

1988). Foraging flights during the pre- and post-breeding periods were found to be 

up to 2km in distance (Jackson, 1988). 

Territory sizes ranging between 5.7ha and 6.9ha have been recorded in Alaska 

(Holmes, 1966), which equate to distances of up to 150m. 

In terms of maximum distances, adults have been recorded foraging up to 3km from 

the location of their brood (Soikkeli, 1970). 


No information pertinent to connectivity was found. 


Pair-formation occurs on breeding territory or on adjacent feeding grounds (Cramp & 

Simmons, 1983). Males perform display flights, during most of the early breeding 

season, at a typical height of 10m to 50m (Holmes, 1966; Cramp & Simmons, 1983). 

The display flight involves a rapid ascent, followed by alternate gliding down and 

regaining of height. 

Display flights occur most frequently between arrival on breeding grounds and pairformation, 

most commonly between 06:00h and 09:00h (Cramp & Simmons, 1983). 

The displays can last from a few seconds to up to approximately 3.5 minutes. 



Territorial behaviour can occur on nesting territory and involve aerial pursuit, ground 

pursuit, and ground combat (Cramp & Simmons, 1983). Display flights, as described 

above, can arise in response to sight or sound of conspecific neighbours. 



Breeding habitat of Scottish birds tends to be wet upland and montane heath, 

generally with frequent pool systems (Lavers & Haines-Young, 1996). Breeding sites 

on upland moors are generally at altitudes of up to 1000m (Cramp & Simmons, 

1983). 



Outside the breeding season, dunlin are generally found along coasts, especially on 

mudflats rich in invertebrate prey that are available as the tide ebbs (Cramp & 


39



A study on the Western Isles found that brood movements are generally within 250m 

from the nest, and occasionally up to 500m (Jackson, 1988). Broods have been 

recorded as travelling up to 1km in two days after leaving the nest (Soikkeli, 1970). 

40

2.16 Curlew 



Curlew tend to forage within 0.5 and 1km of nest sites, with regular foraging up to 

1.5km (authors’ experience). 


A study of breeding curlew at Monk’s Moor, Upper Teesdale, found that first-year 

burned areas were used as nesting habitat at a greater frequency than would be 

expected based on the availability of this habitat (Robson et al., 1995). 


Defence of territory is by both sexes, but mainly the male (Cramp & Simmons, 1983). 

The male marks the territory using an undulating display flight, which usually involves 

a low flight that rises steeply on fluttering wings, followed by a brief hovering and then 

gliding back down. This is then repeated (Cramp & Simmons, 1983). Male display 

flights can be up to 1.5km from the territory centre (authors experience). 


No information on pertinent to connectivity was found. 



Curlews breed in upland areas in Britain, generally up to 550m a.s.l., and 

occasionally up to 760m a.s.l. The Monk’s Moor study which radio-tracked four 

broods (Robson et al., 1995) found chicks showed a preference for first-year burned 

areas, as well as Juncus effusus flush, based on a greater use of these habitats than 

would be expected based on their availability (Robson et al., 1995). 


No information on pertinent to connectivity was found. 



Median distances from the nest for the four broods radio-tracked in the Monk’s Moor 

study were 99m, 196m, 196m, and 267m (mean: 190m), whilst maximum distances 

were 185m, 207m, 318m and 489m (mean: 300m) (Robson et al., 1995). 

41

2.17 Whooper swan 


Foraging range from roosts 

Whooper swans roosting at the Black Cart SPA, Paisley, will regularly fly over 3km 

from their roost to their feeding grounds, and occasionally fly up to 4.5km (Harding, 

2008). In a study during in winter 2007/2008, the majority of recorded flights 

between the roosting and foraging areas were at a height of less than 50m (Harding, 

2008). 

Whooper swans roosting at Loch Leven SPA, Perthshire generally forage 

approximately 4km from their roost site (Ken Shaw pers. comm.). Buckland et al. 

(1990) recorded that whooper swans grazed in the fields surrounding Loch of 

Strathbeg, but that a change from spring to autumn-sown cereals had forced the 

swans to forage further out (up to 30 km). 


Whooper swan is a winter migrant so information on nesting is not pertinent to 

connectivity to SPAs in Scotland. 

2.17.3 Display fights 

Whooper swan is a winter migrant so information on display fights is not pertinent to 

connectivity to SPAs in Scotland. 


Whooper swan is a winter migrant so information on competitive behaviour is not 

pertinent to connectivity to SPAs in Scotland. 


Foraging habitat 

Foraging habitats in wintering areas include lakes and rivers where suitable aquatic 

vegetation occurs, and also flooded areas, stubble fields, and arable crops (including 

potatoes) (Cramp, 1977). 

42

2.18 Wintering geese 


Geese are highly mobile and can be expected to regularly forage on any suitable 

habitat up to 20km from the roost site (Patterson, 2006). 


Information on nesting is not pertinent to connectivity with wintering goose qualifying 

interests of SPAs in Scotland. 


Information on display flights is not pertinent to connectivity with wintering goose 

qualifying interests of SPAs in Scotland. 


Information on competitive behaviour is not pertinent to connectivity with wintering 

goose qualifying interests of SPAs in Scotland. 

2.19 Greylag goose 


Foraging range from roost 

No specific data have been found for greylag goose. However, similar foraging 

distances to those presented for pink-footed goose would be expected. 


Foraging habitats in winter include croplands, stubble, grasslands, and occasionally 

shallow water (Cramp, 1977). Food items are plant material, including roots and 

tubers, green leaves and stems, flower heads, and fruits (Cramp, 1977). 

2.20 Pink-footed goose 



A survey was carried out in 2004, on five days in March and three days in April, to 

determine the feeding distribution of pink-footed geese coming from the roost at Loch 

of Strathbeg, Grampian (Patterson & Thorpe, 2006). From data collected for this 

survey, the distance of foraging flocks from the roost location can be measured, and 

is summarised in Table 6. The maximum distance travelled to forage from Loch of 

Strathbeg was 13.1km. The majority of foraging fields were within 4km in March 

2004, and within 5km in April 2004. Summary figures of the location of these 

foraging fields are shown in Figures 7 and 11 within Patterson & Thorpe (2006). 

A study of foraging locations of pink-footed geese roosting at Cameron Reservoir, 

Fife in 2001/2002 determined that foraging is within 20km of the roost site (based on 

43

data from Allan Brown). Pink-footed geese roosting at Loch Leven forage at 

distances of up to 15km from the roost site (Ken Shaw pers. comm.). 

Table 6 - Distance of foraging flocks from Loch of Strathbeg 

Proportion March 2004 April 2004 

25% 1.5km 2.2km 

50% 3.6km 4.4km 

75% 6.0km 8.2km 

100% 12.4km 13.1km 


Foraging habitats in winter are mainly farmland, including grassland (Cramp, 1977). 

All geese recorded during the 2004 survey of birds from Loch of Strathbeg were 

foraging on grass fields (Patterson & Thorpe, 2006). 

2.21 Greenland white-fronted goose 



For the population of Greenland white-fronted geese wintering on Islay, there are 

many locations where the birds have been known to roost (WWT data). Foraging 

locations of these birds tend to be within 5 and 8km from the roost sites (based on 

SNH count data). 

Greenland white-fronted geese at Kintyre, which forage during the day at 

Rhuriahaorine Point SPA, roost mainly 5km away at the Loch an Fhraioch and Loch 

Ulagadale SPAs, and 6km away at the Loch Garasdale SPA (Richard Walls pers. 

comm., based on CSL data). 


Greenland white-fronted geese forage on the leaves and stems of grasses, with their 

diet supplemented by stubble, grains, and root crops when available (Cramp, 1977; 

Mayes, 1991). 

2.22 Barnacle goose 



Barnacle geese wintering in Scotland originate from either the Greenland or Svalbard 

breeding populations (Owen, 2002). 

77% of the Scottish wintering population of Greenland barnacle geese winter on Islay 

(Trinder et al., 2005). Foraging fields for these birds are within 15km of the main 

roost sites (based on SNH count data) with the majority foraging between less than 1 

44

to about 7 km from the roost (Malcolm Ogilvie pers. comm.). Greenland Barnacle 

Geese wintering on the Western Isles show similar foraging distances from their 

roost sites, foraging within 15km, and often at around 5km (Andrew Stevenson pers. 

comm.). 

The Svalbard population all winter along the Solway Firth (Trinder et al., 2005). 

Based on data from surveys undertaken in the winter of 2004/05 (DH Ecological 

Consultancy, 2005), the majority of foraging locations are within approximately 10km 

of the roost sites, with others within approximately 25km. 


Barnacle geese forage on the leaves and stems of grasses, with their diet 

supplemented by stubble and grains (Cramp, 1977). Studies on Islay have shown 

that birds have a preference for newly reseeded pastures (Percival, 1993). 

45

3. SUMMARY 

This section summarises details on foraging distances for all species and distances 

between alternative nest sites for relevant species. The distances represent a 

summary, where possible, of all the data reviewed within this document. We feel the 

values presented here would be the most relevant to judging connectivity to SPAs. 

3.1 Foraging ranges during breeding season 

Foraging distances during the breeding season are summarised for all species in 

Table 7. 

Table 7 - Summary of foraging distances during breeding season 

Species 

Red-throated 

diver 

Black-throated 

diver 

Foraging range from nest site during breeding season 

Generally less than 8km, but regular flights of 11-13.5km 

recorded on Western Isles. 

Likely to be less than 10km. 

Red kite 

Core range of 4km, with maximum range of up to 6km. 

Hen harrier Female core range of 1km, with majority of foraging within 2- 

3km, and maximum range of

3.2 Foraging ranges during winter season 

Foraging distances during the winter are summarised in Table 8 for whooper swan, 

greylag goose, pink-footed goose, Greenland white-fronted goose, and barnacle 

goose. 

Table 8 - Summary of foraging distances during winter season 

Species 

Whooper swan 

Greylag goose 

Pink-footed goose 

Greenland white-fronted goose 

Barnacle goose 

Foraging range from night roost during 

winter season 

Core range of less than 5km. 

Core range of 15-20km. 

Core range of 15-20km. 

Core range of 5 – 8 km. 

Core range of 15km, with maximum recorded 

distance of up to 25km. 

3.3 Distances between alternative nest sites 

Distances between alternative nest sites are summarised for relevant species in 

Table 9. 

47

Table 9 - Summary of distances between alternative nest sites 

Species 

Red-throated diver 

Black-throated diver 

Red kite 

Hen harrier 

Goshawk 

Golden eagle 

Osprey 

Merlin 

Peregrine 

White-tailed eagle 

Short-eared owl 

Black grouse 

Golden plover 

Greenshank 

Dunlin 

Curlew 

Distance between alternative nest sites 

Distances of 1km are not unusual. 

Likely to be similar to above: within 1km. 

Within 1km. 

Generally within 1km. 

Generally 200-300m apart, but can move to new 

territories up to 2.5km away. 

Less than 3km apart in high density areas; up to 6km 

apart elsewhere. 

Within 2km. 

Generally within 500m, but can be up to 1.5km. 

Mean distance of 3km, and maximum distance of 6.5km. 

Generally within 3km, and a maximum distance of 12km. 

No information. 

Within 2km range. 





48

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