Meeting Abstract

S10.7  Friday, Jan. 7  Cold acclimation, migration, and phenotypic compromises in a long distance migratory shorebird VÉZINA, F.; Université du Québec à Rimouski francois_vezina@uqar.ca

Although there is considerable knowledge on wintering ecology of migratory shorebirds, little is known on phenotypic adjustments to cold and how this may interact with other constraints in species spending their winters at northern latitudes. In this talk, I will review our recent work on physiological adjustments in relation to winter and migratory constraints in a species well known for its phenotypic flexibility: the red knot (Calidris canutus islandica). Islandica are the northernmost wintering subspecies of knots, spending their winters on cold and windy mudflats of Western Europe and breeding in the Canadian and Greenlandic High Arctic. I will show how these birds improve their winter thermogenic capacity and cold endurance by simple body mass adjustments and how this may be compromised when conflicting wintering constrains are co-occurring. I will also discuss energy management strategies in these molluscivore birds during extended periods of winter fasting such as those associated with high tide and stormy winter weather. Finally I will present our recent work on gut reconstruction following migration to the Arctic breeding ground, asking whether this may constrain digestive capacity and explain an observed steady increase in basal metabolic rate over time.