Endogenous reserve dynamics of northern common eiders wintering in Greenland

Simon Fraser University Biological Sciences 8888 University Drive V5A 1S6 Burnaby BC Canada
Polar Biology (Impact Factor: 1.59). 06/2006; 29(7):585-594. DOI: 10.1007/s00300-005-0093-2


Endogenous reserves influence both survival and reproduction of many waterfowl species, but little is known about reserve levels of most species during the nonbreeding season, particularly those wintering at high latitudes. We investigated whether age, sex, and season were related to carcass composition of northern common eiders (Somateria mollissima borealis) wintering in southwest Greenland during 1999–2002. Adults carried more lipid and protein than juveniles during all winters. Among both age classes, males and females had similar fat levels but males carried slightly more protein. There was no dramatic seasonal variation in lipid or protein content. This suggests that during the period of this study, these eiders did not experience large-scale nutritional shortfalls. As predicted, Greenlandic eiders carried more lipid reserves than eider populations wintering in more temperate environments. Contrary to prediction, there was little relation between reserve levels and photoperiod, ambient temperature, or hunting disturbance intensity. Our results suggest that both sexes are equally capable of dealing with nutritional deficits, and that juvenile birds are more prone to nutritional stress as evidenced by their consistently poorer body condition.

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Available from: Sarah Emily Jamieson, Oct 02, 2015
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    • "In contrast to dabbling ducks (Anas spp.), body mass and composition are poorly documented for seaducks due to difficulties in obtaining specimens for laboratory analysis. There are only a few papers concerning this group of birds and all but one are from North America (Leafloor et al. 1996, Lovvorn et al. 2003, Bond and Esler 2006, Jamieson et al. 2006, Fox et al. 2008). In particular, studies of the body composition of Velvet Scoters (Melanitta fusca), a seaduck species of conservation concern mentioned in The Bird Directive (Directive 2009/147/EC of the European Parliament and of the Council of 30 November 2009 on the conservation of wild birds), are lacking. "
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    ABSTRACT: Body mass and body composition of 27 adult Velvet Scoters (Melanitta fusca) were studied. These birds were collected from January to March in the Gulf of Gdańsk, Poland. Body mass, fat, and protein contents of both males and females decreased significantly between mid and late winter, possibly because of a physiological process or a result of worsening environmental conditions. In mid-winter, the mean body mass of males and females did not differ significantly, whereas in late winter the difference in body mass between sexes became prominent. There was no difference in fat mass between the sexes, but females had higher lipid indexes despite their smaller size. The lack of expected fat mass increase in late winter may be due to the spring migration strategy of Velvet Scoters, which apparently opt to fly short distances rather than make long non-stop flights after departure from the Gulf of Gdańsk. Body mass was the best predictor of fat mass accumulated by Velvet Scoters wintering in the Gulf of Gdańsk.
    Oceanological and Hydrobiological Studies 09/2012; 41(3). DOI:10.2478/s13545-012-0023-1 · 0.67 Impact Factor
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    • "winter, and human exploitation (Jamieson et al. 2005; Merkel 2006; Mosbech et al. in press). "
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    ABSTRACT: Southwest Greenland provides wintering grounds for 70% (∼460,000) of the northern common eider (Somateria mollissima borealis) population. From 241 gullet samples (esophagus and proventriculus content) collected over three winters (1999–2002) near Nuuk, we identified 39 species consumed by the eiders. In contrast to studies elsewhere, fresh mass of the diet was dominated by soft-bottom species: the bivalve Mya eideri (32.8%) and the polychaete Pectinaria spp. (24.2%). The hard-bottom blue mussel (Mytilus edulis), usually the dominant prey of common eiders, was only the fourth most important diet species (7.5%). Overall, bivalves accounted for 56% of the diet. Twenty-seven prey species were minor foods with aggregate fresh mass of only 5.5%. Diets of males and females were similar, whereas juveniles consumed greater mass of crustaceans and less of bivalves. Diet diversity was higher in mid-winter than late winter, and higher in coastal habitats than in fjords. Within one important wintering area the results indicate that optimal size of blue mussels may be depleted over winter.
    Polar Biology 12/2006; 30(2):227-234. DOI:10.1007/s00300-006-0176-8 · 1.59 Impact Factor
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    ABSTRACT: Body size affects foraging and forage intake rates directly via energetic processes and indirectly through interactions with social status and social behaviour. Ambient temperature has a relatively greater effect on the energetics of smaller species, which also generally are more vulnerable to predator attacks than are larger species. We examined variability in an index of intake rates and an index of alertness in Lesser Snow Geese Chen caerulescens caerulescens and Ross's Geese Chen rossii wintering in southwest Louisiana. Specifically we examined variation in these response variables that could be attributed to species, age, family size and ambient temperature. We hypothesized that the smaller Ross's Geese would spend relatively more time feeding, exhibit relatively higher peck rates, spend more time alert or raise their heads up from feeding more frequently, and would respond to declining temperatures by increasing their proportion of time spent feeding. As predicted, we found that Ross's Geese spent more time feeding than did Snow Geese and had slightly higher peck rates than Snow Geese in one of two winters. Ross's Geese spent more time alert than did Snow Geese in one winter, but alert rates differed by family size, independent of species, in contrast to our prediction. In one winter, time spent foraging and walking was inversely related to average daily temperature, but both varied independently of species. Effects of age and family size on time budgets were generally independent of species and in accordance with previous studies. We conclude that body size is a key variable influencing time spent feeding in Ross's Geese, which may require a high time spent feeding at the expense of other activities.
    Ibis 12/2008; 151(1):134 - 144. DOI:10.1111/j.1474-919X.2008.00895.x · 1.92 Impact Factor
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