Seasonal variation in survival, weights, and population counts of blue penguins (Eudyptula minor) in Otago, New Zealand

To estimate the cost of moulting on blue penguin survival we conducted a 17-month mark recapture study. We used a round-up trap set at sunset to catch penguins returning from the sea to their burrows. Survival and density were modelled using capture-recapture models. We found that survival was lower in the post-moult months compared with the rest of the year. No mortality was found during the period from egg laying to chick fledging. The peak of the breeding season was the time when the population size could be estimated most accurately. However, 3 trapping nights seems to be too low for reliable population size estimation. From a subsample of the captured penguins we found weights similar to those recorded previously for this species in Otago.