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: 2.01). 01/2006; 29(7):585-594. DOI: 10.1007/s00300-005-0093-2

ABSTRACT 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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: An understanding of how hunting affects migratory birds is essential for reaching sustainable management of hunted populations. The purpose of our paper was to synthesise current knowledge of autumn and winter hunting disturbance on migratory birds and to describe a case study in Hellas (Greece). Hunting may influence migratory bird behaviour and movements, but studies have not found a corresponding increase in non-hunting mortality factors or any reduction in feeding, body condition, breeding success and any long-term population decrease. We developed a diagnostic procedure which provides a tool for assessing the potential susceptibility of a species or group of species to hunting disturbance. The application of this procedure showed that the influence of hunting disturbance on quarry species is inverse to hunting harvest. This new insight should be considered in a holistic hunting management approach.
    Wildlife Biology 07/2013; 19(2):113-125. · 1.10 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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. · 2.36 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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 01/2012; 41(3). · 0.40 Impact Factor

Full-text (2 Sources)

Available from
May 15, 2014