Survival of Female Harlequin Ducks During Wing Molt

Survival rates of waterfowl during wing molt have rarely been described, leading to uncertainty about the importance of this annual cycle stage for management. We quantified survival probability of 247 radiomarked female harlequin ducks (Histrionicus histrionicus) during wing molt in Prince William Sound, Alaska, USA. The daily survival rate (DSR) was extremely high (DSR 1⁄4 0.999; 95% CI: 0.994– 1.000) during the 37-day interval over which remiges were replaced and individuals were rendered flightless. Our DSR estimate corresponded to a cumulative survival probability of 0.99 (95% CI: 0.81–1.00) for the 20 August–15 October postbreeding period as a whole, which is appreciably higher than estimates that have been derived for breeding or overwintering stages. We conclude that wing molt is a comparatively safe stage of the annual cycle for harlequin ducks that does not constrain population growth rate, with the implication for wildlife managers being that, in the absence of anthropogenic influences, management prescriptions may be most effective when focused on other stages of the annual cycle. ( JOURNAL OF WILDLIFE MANAGEMENT 71(4):1220–1224; 2007) DOI: 10.2193/2006-433