Evaluating the Breeding Ecology of Pigeon Guillemots (Cepphus columba) on Alcatraz Island, 2015
Seher V. 2016. Evaluating the Breeding Ecology of Pigeon Guillemots (Cepphus columba) on Alcatraz Island, 2015
Pigeon guillemots (Cepphus columba) began nesting on Alcatraz in 1982, but their breeding ecology and reproductive success on the island has never been fully evaluated until recently. This project collected baseline data on the breeding phenology, diet, and reproductive success of pigeon guillemots on Alcatraz during the 2015 season. Out of 28 possible nest sites monitored, 18 were active with eggs or chicks and 14 were analyzed for this project. The mean date eggs were laid was June 8, and the mean date chicks fledged was August 10. On average, the incubation period was 29 days and the chicks fledged at 39.7 days. Ten out of 14 sites were successful in fledging one chick and productivity averaged 0.71 fledglings per monitored site. The diets of guillemots consisted mainly of sculpin/midshipmen, flatfish, shrimp, and tonguefish and prey delivery rates ranged from 8.8 to 13.7 prey items per day.
- Type
- Unpublished Report
- Authors
- Seher, Victoria
- Date of Issue
- 2016-03
- Units
- GOGA
- Keywords
- alcatraz pigeon guillemot seabird avian nesting breeding ecology diet reproductive success nest Cepphus columba egg chick
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Birds