Allocation of nutrients to reproduction at high latitudes: Insights from two species of sympatrically nesting geese

Abstract

ABSTRACT. Understanding factors that determine sources of nutrients for reproduction is vital to interpreting different life history strategies used among species, within species, and among taxa. We used stable carbon isotope analysis (δ13C) to compare the relative use of endogenous and exogenous nutrients during egg synthesis between two species of geese, Canada Geese (Branta canadensis interior) and Lesser Snow Geese (Chen caerulescens caerulescens), nesting on Akimiski Island, Nunavut. We estimated that Canada Geese used 49 ± 1.1% (SE), 61 ± 1.3%, and 51 ± 1.1% endogenous nutrients for albumen, yolk protein, and yolk lipid, respectively. Lesser Snow Geese used significantly less endogenous nutrients during clutch formation, allocating only 25 ± 1.2%, 36 ± 1.5%, and 34 ± 1.7% endogenous nutrients for albumen, yolk protein, and yolk lipid, respectively. Although the proportion of endogenous nutrients allocated to eggs did not vary by year in Canada Geese, proportions varied significantly among years in S...