Breeding of the endemic Azores Woodpigeon Columba palumbus azorica: a two-year study on Pico Island

Abstract

ABSTRACT Capsule The Azores Woodpigeon Columba palumbus azorica nested in low altitude forests dominated by native Morella faya, and had an extended breeding season, with high failure rates, particularly during incubation. Aims This work aimed to study the breeding phenology, nesting habitat, clutch size and nesting success of the Azores Woodpigeon. Methods Areas for nest searching were defined randomly. A total of 125 nests were monitored during two breeding seasons on Pico Island, Azores. Survival rates were calculated according to Mayfield method. Results Although most nests were found in forests dominated by introduced Pittosporum undulatum, our study highlights a strong selection for those dominated by native Morella faya. The Azores Woodpigeon seemed to avoid native Laurel forest for nesting. There was a preference for nesting in small or medium trees. Nests heights ranged between 3 and 14 m, with a mean (± se) of 7.0 ± 0.2 m. Egg laying occurred from late-February to early-August (in 2016) or to early-September (in 2017). Clutch size did not vary with time; its mean value was 1.72 ± 0.05 eggs (range: 1–2 eggs). The probability of breeding success was estimated at 0.204 ± 0.113 in 2016 and 0.152 ± 0.103 in 2017. In both years, breeding failure mostly occurred during incubation. Survival differed between the two main nesting habitats, being higher in forests dominated by Morella faya. Conclusions The Azores Woodpigeon does not seem to rely on native Laurel forest for nesting, which confirms previous results. Its preference and higher survival in another strongly threatened habitat is cause for concern. The probability of breeding success was higher than previously reported but still low. Illegal hunting of adult birds, because of alleged damages to crops, might partially explain the high proportion of eggs that did not hatch.