Several Cooper Island youngsters return to breed for first time
By George Divoky
30 nests with eggs–about half of the active nests! In recent years, few eggs have been laid in July, but not this year.
Adult survival is apparently as low as last year (about 75 percent compared to the long-term average of 90 percent). Unlike last year, there are a number of 3-yr-olds that fledged in 2015 and have reached the age when guillemots first breed.
While last year’s many widowed birds paired with their widowed neighbors (resulting in the decrease in nest sites) this year new birds are occupying the vacancies resulting from the increased mortality.
Guillemots typically don’t breed until their third year. There are even a few pairs this year with both members consisting of returning Cooper birds breeding for the first time.
Just finished the adult census as a Peregrine kept birds offshore or in sites for 2 days.
Getting the WeatherPort (which is basically a heavy-duty canvas structure, similar to a yurt) set up now — more later.
This field report is part of an ongoing series titled Arctic Change centered around George Divoky’s 44th field season studying Black Guillemots, sea ice, and climate change on a remote Arctic island off the coast of Alaska. To donate and support Divoky’s work on Cooper Island, visit the Friends of Cooper Island.
Black Guillemots Life History by Cornell Lab of Ornithology
A Cooper Island Field Report
By George Divoky
