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

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 1980's. Stored endogenous nutrients are critically important to the life cycle of arctic geese as they are used 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. Arctic geese were collected from October–February 2015–2016 and 2016–2017 in eastern Arkansas, USA. Proximate analysis was used to determine size of lipid and protein stores as an index of body condition. Protein stores were more stable through time than lipids, but a slight increase was observed in all species as winter progressed. Mean lipid stores were dynamic and were highest in November (x̄ _{greater white-fronted} = 442.6 g, x̄ _snow = 308.0 g, x̄ _Ross's = 268.25 g) and lowest in February (x̄ _{greater white-fronted} = 215.1 g, x̄ _snow = 142.0 g, x̄ _Ross's = 103.0 g). 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; the decline may have been driven by a combination of factors such as resource depletion, a shift in dietary needs, physiological factors, hunting pressure, and increased energetic demands. An improved understanding of the role that "non-traditional" wintering grounds exert on the nutrient dynamics of arctic geese may aid in the management of growing and shifting populations.

Keywords: agriculture, Arkansas, endogenous, greater white-fronted goose, lesser snow goose, lipids, proximate analysis, Ross's goose