Conservation Science in the RSPB 2006

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14 Monitoring and indicators The RSPB is involved in a wide variety of monitoring schemes for birds and, to a lesser extent, other taxonomic groups. Increasingly, we are helping develop monitoring schemes outside the UK, and are using monitoring data to produce policy-relevant indicators that measure the changing state of the environment.
15 A census method for crossbills Crossbills are not easy to census because, unlike many passerines, they do not often sing at dawn. Occurring in conifer woods, they are quiet when feeding and are generally seen only when flying overhead giving their characteristic flight calls. However, they respond readily to playback of excitement calls broadcast from loudspeakers. Not only do they fly towards this lure, but they often respond by calling. Tape-recording these distinctive excitement calls allows each species (Scottish, parrot and common) to be identified subsequently from sonograms. This playback technique is a potential census method for these crossbill species, but it is necessary to understand and measure the factors that could influence the response to the lure. Fieldwork was carried out between December and April in highland Scotland between 2002 and 2005. Birds were first located visually or by sound, and then the lure call was played for a maximum of five minutes. The number of birds, their behaviour prior to the playback, the type of woodland, date, time of day and distance from the lure were all recorded. Calls were also taperecorded for later identification. One hundred and fifty-two tests were carried out on all crossbills. The only significant factor determining likelihood of response was distance from the lure. Birds farther away were less likely to respond. Crossbills are lured from an effective area of 18 ha around each point at which the lure is played. Pilot surveys were then carried out at Abernethy Forest and Glenmore Forest in Strathspey. Playback was used over a grid of points and estimates for the density of crossbills were 2.8 and 9.8 birds per km 2 respectively. Now that we have a validated survey technique for crossbills, we are in a position to make the first survey of the Scottish crossbill, Britain’s only endemic bird. Contact: ron.summers@rspb.org.uk The study was carried out in collaboration with the Centre for Research into Ecological and Environmental Modelling, University of St Andrews. Buckland ST, Summers RW, Borchers DL and Thomas L (2006) Point transect sampling with traps or lures. Journal of Applied Ecology 43, 377–384. Summers RW, Jardine DC, Marquiss M and Rae R (2002) The distribution and habitats of crossbills Loxia spp. in Britain, with special reference to the Scottish Crossbill Loxia scotica. Ibis 144: 393–410. See also: 2001: 23; 2004: 36 The probability of crossbills responding decreases with distance from the playback lure. The fitted line is from a logistic regression model of the frequency of responses (1) and non-responses (0) at different distances. Some data points include multiple records. Probability of response 1 0.8 0.6 0.4 0.2 Dusan Boucny (rspb-images.com) 0 0 100 200 300 400 500 600 700 800 900 Distance from lure (m) Crossbill
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Page 4 and 5: Arctic tern on nest Andy Hay (rspb-
Page 6 and 7: 2 Willow warbler Ben Hall (rspb-ima
Page 8 and 9: 4 Funding The RSPB has a policy of
Page 10 and 11: 6 Department of Zoology, University
Page 12 and 13: 8 The application of science
Page 14 and 15: 10 Andy Hay (rspb-images.com) • T
Page 16 and 17: 12 Finding a cause for and solution
Page 20 and 21: 16 Repeat Woodland Birds Survey Sev
Page 22 and 23: 18 The 2004 nightjar survey Restora
Page 24 and 25: 20 Declines in migrant birds breedi
Page 26 and 27: 22 Mapping moorland habitats for bi
Page 28 and 29: 24 The 2004 hen harrier survey In c
Page 30 and 31: 26 The ecology of threatened specie
Page 32 and 33: 28 mechanisms for migration. Techni
Page 34 and 35: 30 Andy Hay (rspb-images.com) Insta
Page 36 and 37: 32 Yellow wagtails breeding on arab
Page 38 and 39: 34 These results indicate the scale
Page 40 and 41: 36 Dunlin Mike Lane (rspb-images.co
Page 42 and 43: 38 survival rates of adult and juve
Page 44 and 45: 40 Woodpigeon Andy Hay (rspb-images
Page 46 and 47: 42 Managing the risk of disturbance
Page 48 and 49: 44 Acid grassland re-creation on fo
Page 50 and 51: 46 Ouse Washes Andy Hay (rspb-image
Page 52 and 53: 48 However, it soon became clear th
Page 54 and 55: 50 PhD training The RSPB funds and
Page 56 and 57: 52 Publications The complete list o
Page 58 and 59: 54 Dmitrenok M, Puglisi L, Demongin
Page 60 and 61: 56 and breeding performance of grea
Page 62: 58 Summers RW (2005) The History an

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