Low oxygen-carrying capacity of blood may increase developmental instability of molt in migrating waders

Abstract

ABSTRACT. The degree of asymmetry in feather replacement may be considered a reliable measure of developmental instability of avian molt. Although empirical evidence exists for the fitness consequences of molt asymmetry, the proximate cause of asymmetrical molt remains unknown. We tested for the possibility of a link between asymmetry in feather replacement and hemoglobin concentration of first-year Common Snipe (Gallinago gallinago) during the partial postjuvenile molt. Advancement and symmetry of molt were determined for 637 first-year Common Snipe captured at Jeziorsko reservoir, central Poland, during autumn migration. We found that the probability of asymmetrical molt did not vary with date of capture (W = 1.66, P = 0.20), but Common Snipe with lower hemoglobin concentrations had a higher probability of asymmetrical molt (W = 5.22, P = 0.022). Because Common Snipe molt during migration, high oxygen-carrying capacity of blood is presumably necessary to meet aerobic demands of the tissues during long-d...