The Greenland White-fronted Goose Anser albifrons flavirostris

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land White-fronted Geese in late winter and spring are at least likely to affect the ability of an individual to undertake the flight to Iceland successfully. Furthermore, the levels of stores available on departure from the wintering areas could potentially influence the extent of stores available for the onward flight to Greenland and ultimately for investment in reproduction. Clearly, any contribution that accumulated stores can make to body maintenance, egg laying and incubation (in the case of the female) and to territorial defence and mate protection (amongst males) is likely to contribute to the reproductive output of a goose pair. In the case of the Greenland White-fronted Goose, there are three sources of proxy data that can be used to follow the changes in body constituents or in fat stores throughout the course of the winter. The first is the use of catch data from Wexford Slobs, where geese have been captured using cannon nets each year since 1983/84. All have been aged and sexed and weighed to the nearest 50 g before being fitted with individual marks and metal tarsus rings (see MS7 for full details). Most catching has taken place in the autumn, especially in October/November, but some birds have been caught in all months from October to April. Fitted regression lines to the full data set of indi- Body mass (g) Body mass (g) 28 4000 3500 3000 2500 2000 Adult females 1500 1-Oct 20-Nov 9-Jan Date of capture 28-Feb 18-Apr 4000 3500 3000 2500 2000 Juvenile females 1500 1-Oct 20-Nov 9-Jan Date of capture 28-Feb 18-Apr Body mass (g) Body mass (g) vidual weight regressed on date shows a polynomial relationship between body mass and date for all age and sex classes (Figure 3.1). These patterns represent a slight decline in mass from arrival until December followed by a gradual accumulation until departure in early to mid April. These data represent the cumulative data over many years, but the general trend from January onwards is confirmed by a second method. A series of catches carried out throughout the spring of 1999 specifically to assess within-winter patterns of body mass change concentrated on late winter/spring catches of small numbers of pairs. The results are shown in Figure 3.2 and confirm the general pattern of relatively slow accumulation of body mass throughout the latter half of the winter at Wexford. The third proxy method of assessing body mass is the use of field scores of abdominal profiles of geese wintering at Wexford. Owen (1981) developed the use of abdominal profiles as a non-consumptive method of assessing the fat deposits of geese in the field. The method depends upon the fact that fat stored in the abdomen is a reliable index of general fat stores accumulated throughout the body (Thomas et al. 1983), and the levels of abdominal fat storage can be assessed using a 4000 3500 3000 2500 2000 Adult males 1500 1-Oct 20-Nov 9-Jan Date of capture 28-Feb 18-Apr 4000 3500 3000 2500 2000 Juvenile males 1500 1-Oct 20-Nov 9-Jan Date of capture 28-Feb 18-Apr Figure 3.1. Body mass determinations of Greenland White-fronted Geese caught at Wexford during the winters 1983/84-1998/99 combined, showing fitted polynomial regressions (see Appendix 1 for statistics relating to figures 1 ).
Body mass (g) 3500 3000 2500 adult male adult female 1999 females 1999 males 2000 21-Oct 20-Nov 20-Dec 19-Jan 18-Feb 19-Mar 18-Apr Date of capture Figure 3.2. Body mass determinations of individual adult male and adult female Greenland White-fronted Geese caught at Wexford in spring 1999, compared to regression models for these age and sex classes from 1983/94-1998/99 combined (from Figure 3.1). predetermined visual scoring system. In Greenland White-fronted Geese, there is a good correspondence between this measure and overall body mass (see chapter 4). This method of assessing changes in abdomen profile has been applied to collared individual Greenland White-fronted Geese wintering at Wexford Slobs since 1984/85, enabling the compilation of median field scores for each half-month period there over many years. These values are presented in Figure 3.3, which demonstrates a remarkable degree of between year variation in arrival condition of birds in autumn, but a high degree of convergence towards attainment of similar scores by the time of the spring departure. Combining all years suggests little difference between the sexes in the rate of accumulation of abdominal fat stores (Figure 3.4). The patterns of change in this measure are very similar to those of direct body mass determina- Median abdominal profile score 4 3 2 1 0 early Oct late Oct early Nov late Nov early Dec late Dec early Jan late Jan early Feb late Feb early Mar late Mar tion, suggesting that geese only gradually accumulate fat deposits over the period from mid December until their departure in mid April. It would therefore seem that unlike other studied geese in winter (e.g. Svalbard Barnacle Geese wintering in western Scotland, Owen et al. 1992), Greenland White-fronted Geese at Wexford are generally able to maintain and even increase body mass during the short day lengths of December and January. This is probably due to the generally mild prevailing weather conditions and favourable feeding conditions at Wexford, which probably reflects conditions throughout much of the winter range. Mayes (1991) showed that only when ambient temperatures averaged –0.5ºC in January 1985, and the frozen substrate precluded geese from probing for nutritious stolons, did Green- early Apr late Apr 1984/85 1985/86 1986/87 1987/88 1988/89 1989/90 1990/91 1991/92 1992/93 1993/94 1994/95 1995/96 1996/97 1997/98 1998/99 Figure 3.3. Half-monthly median abdominal profile scores of Greenland Whitefronted Geese wintering at Wexford Slobs, SE Ireland during the years 1984/ 95-1998/99. Median abdominal profile score 4 3 2 1 0 early Oct late Oct early Nov late Nov female male early Dec late Dec early Jan Figure 3.4. Half-monthly median abdominal profile scores for adult male and female Greenland Whitefronted Geese wintering at Wexford Slobs, SE Ireland for all years combined 1984/95-1998/99. late Jan early Feb late Feb early Mar late Mar early Apr late Apr land White-fronted Geese lose condition at a semi-natural grassland site. Similarly, Stroud (unpubl. data) studying Greenland Whitefronted Geese on Islay found median API scores fell by 1.4-2.0 units during the subzero temperatures of December 1980. Prolonged periods of frost and temperatures to –10ºC at that time stopped grass production and denied geese access to peatland food items at the roosts. 29
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Page 5 and 6: Contents Summary ..................
Page 7 and 8: Summary The Greenland White-fronted
Page 9 and 10: Greenland White-fronted Geese are u
Page 11 and 12: Dansk resumé Den grønlandske blis
Page 13 and 14: 1 Introduction 1.1 Why Greenland Wh
Page 15 and 16: The Greenland White-fronted Goose i
Page 17 and 18: more direct measures of 'body condi
Page 19 and 20: 2Limits to population size in recen
Page 21 and 22: Despite the morphological similarit
Page 23 and 24: Scotland, the wettest peat soils we
Page 25 and 26: of this goose population. At the sa
Page 27 and 28: Spring count 16000 12000 8000 4000
Page 29: 3 Accumulation of body stores and t
Page 33 and 34: h -1 and none showed any sign of re
Page 35 and 36: labelled water), the precise extent
Page 37 and 38: 4 Spring staging in Iceland and the
Page 39 and 40: Body mass (g) Body mass (g) 4000 35
Page 41 and 42: Goose droppings/m 2 6 5 4 3 2 1 0 P
Page 43 and 44: er 3KJ was a behaviourally dominant
Page 45 and 46: 5 Pre-nesting feeding 5.1 Introduct
Page 47 and 48: imagery and searches in helicopters
Page 49 and 50: 6 Reproduction 6.1 Breeding distrib
Page 51 and 52: predicted that at the end of this p
Page 53 and 54: Percentage of juveniles Figure 6.1.
Page 55 and 56: Mean age of first breeding 8 7 6 5
Page 57 and 58: periods in each winter as the exten
Page 59 and 60: Geese, it might be expected that in
Page 61 and 62: 7 Moult of flight feathers 7.1 Intr
Page 63 and 64: mass at different stages of regrowt
Page 65 and 66: of available fresh green growth of
Page 67 and 68: 8 Survival 8.1 Introduction Almost
Page 69 and 70: the hunting mortality rate K t for
Page 71 and 72: during the period when the populati
Page 73 and 74: lands. This process was certainly u
Page 75 and 76: 9 Synthesis 9.1 Anticipatory acquis
Page 77 and 78: Mass based on API scores 3600 3200
Page 79 and 80: social system has traditionally reg
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ers (J. Madsen unpubl. data). In th
Page 83 and 84:
limitation which operates during an
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NUTRIENT & ENERGY ACCUMULATION RATE
Page 87 and 88:
eeding geographical locations respe
Page 89 and 90:
10 Acknowledgements A thesis is sup
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mark and to Ebbe Bøgebjerg for the
Page 93 and 94:
L. Kramer, J.N. Kristiansen, T. Lai
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Marked Individuals in the Study of
Page 97 and 98:
mussels, Mytilus edulis. Journal of
Page 99 and 100:
Nichols, J.D. (1991) Extensive moni
Page 101 and 102:
Thompson, S.C. & Raveling, D.G. (19
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12Appended manuscripts 1: Fox, A.D.
Page 105:
National Environmental Research Ins
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The Greenland White-fronted Goose Anser albifrons flavirostris

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