Pamela Denmon, Bryan D. Watts, Fletcher M. Smith
Waterbirds 36 (2), 156-165, (1 June 2013) https://doi.org/10.1675/063.036.0205
KEYWORDS: American Oystercatcher, Haematopus palliatus, predation, reproductive success, video monitoring, Virginia
Nest failure has often been identified as a factor affecting American Oystercatcher (Haematopus palliatus) survivorship. To examine causes of nest failure, small digital cameras were deployed between 6 April and 15 July 2005 on American Oystercatcher nests on Fisherman Island National Wildlife Refuge located in Northampton County, Virginia. Twenty-five attempts, representing 22 different pairs, were recorded resulting in 7,570 hr of video footage. Nest survivorship was 44% (n = 11). High tide events associated with coastal storms were the largest source of nest loss (24%, n = 6), followed by predation on eggs (16%, n = 4). Nest abandonment, unknown factors, and infertile eggs accounted for the remaining 16% (n = 4) of nests. The main predator was Fish Crows (Corvus ossifragus). While American Oystercatchers were incubating, 211 instances were recorded where individuals of 22 species entered the field of view of video cameras. The most common species entering included Boat-tailed Grackle (Oidscalus major) (22.7%), white-tailed deer (Odocoileus virginianus) (11.4%), Brown Pelican (Pelecanus occidentalis) (10.9%), Willet (Tringa semipalmata) (9.0%), and ghost crab (Ocypode quadrata) (7.1%). A wide range of responses to intruders from no reaction to permanent nest abandonment were displayed by incubating American Oystercatchers. The majority (65.9%, n = 139) of encounters were met with no reaction followed by fleeing the nest area (17.5%, n = 37), chasing the intruder (8.5%, n = 18), piping (7.6%, n = 16), and abandoning the nest (< 1.0%, n = 1). All predation events occurred when American Oystercatchers left nests unattended.