Paul Curtis, Jennifer Arnold, Stephen Oswald (Funded by NYS DEC)
Studies of Common Terns on Oneida Lake by Steve Oswald and Jennifer Arnold (Penn State University) in collaboration with Paul Curtis continued the long-term research program that has been going on since the 1970's. A fulltime field tech (Ryan Hartman) was employed on the project and several CBFS summer interns took day trips to the islands to learn about waterbird breeding colonies, conservation and management. In 2021, in addition to basic management and monitoring, several research projects were begun, including a comparison of methods to estimate breeding success, piloting GPS loggers to determine foraging movements, testing low-intensity lighting as a predator deterrent, and scaling up recapture efforts to study population demography. Regular management activities included reducing competition from nesting gulls using control methods (e.g. exclusion grids), vegetation control, providing chick shelters, and documenting predator activity. Breeding terns faced several challenges this year. Nesting density was high on Willard Island, an unstable, shell island that experienced significant erosion during summer storms, causing competition for nesting space and nest loss. Terns on Little Island also faced intense competition for nesting space, this time with Ring-billed Gulls. Terns persisted in nesting until late July, but frequent visits by a Black-crowned Night Heron at this time meant that these late nests were largely unsuccessful. Overall, 2021 was by far the most successful breeding year for terns at Oneida Lake in almost a decade. Peak nest count was 461 over two breeding islands and ~390 chicks were fledged overall. However, even this productivity was below that required for colony stability suggesting that immigration is currently responsible for colony persistence. Ongoing erosion of islands and seasonal nest predation make continued management and island restoration essential if NYSDEC goals for nesting numbers and productivity are to be realized.