Temporal Trends in Body Condition of Arctic Geese Wintering in the Mississippi Alluvial Valley

Abstract

Abstract Midcontinent populations of arctic nesting geese (hereafter, arctic geese), including greater white-fronted geese Anser albifrons frontalis, lesser snow geese Anser caerulescens caerulescens, and Ross's geese Anser rossii, have increased in abundance and shifted their winter distribution in recent decades. Consequently, the number of arctic geese wintering in the Mississippi Alluvial Valley (MAV) has increased since the 1980s. Stored endogenous nutrients are critically important to the life cycle of arctic geese as the geese use these stored nutrients to complete long-distance migration events, survive harsh winters, and supplement nutrients needed for reproduction. This study tracked temporal changes in body condition of arctic geese during the wintering period. We collected arctic geese from October–February 2015–2016 and 2016–2017 in eastern Arkansas. We used proximate analysis to determine size of lipid and protein stores as an index of body condition. Protein stores were more stable through time than lipids, but we observed a slight increase in all species as winter progressed. Mean lipid stores were dynamic and were highest in November and lowest in February. Greater white-fronted geese arrived earliest to the MAV and experienced an increase in endogenous lipid stores during early winter when high-energy food resources were most abundant. Conversely, snow and Ross's geese arrived to the MAV later and did not appear to increase their lipid stores upon arrival. All three species experienced a decline in stored lipid mass as winter progressed; a combination of factors such as resource depletion, a shift in dietary needs, physiological factors, hunting pressure, and increased energetic demands may have driven the decline. An improved understanding of the role that “nontraditional” wintering grounds exert on the nutrient dynamics of arctic geese may aid in the management of growing and shifting populations.