Site Fidelity, Residency, and Sex Ratios of Wintering Ruby-throated Hummingbirds (Archilochus colubris) on the southeastern U.S. Atlantic Coast

Abstract

Ruby-throated Hummingbirds (Archilochus colubris) are common and widespread but little is known about their winter ecology anywhere within their nonbreeding range, and no studies have been conducted on the individuals that now overwinter along the southeastern Atlantic coast of the United States. From 2008–2012, I examined the winter survivability, site fidelity, residency, and age and sex ratios of Ruby-throated Hummingbirds at one location in coastal South Carolina. I investigated whether the wintering population there was migratory or sedentary. Winter site fidelity was 19.4% overall (14.6% for males and 31.6% for females), which is similar to or higher than return rates found in studies near the Gulf of Mexico coast, 300 km to the south. The rate of winter residency was 26.3%. Juvenile sex ratios were significantly male biased, suggesting possible latitudinal sexual segregation, although more study is needed. Only one bird banded during spring, summer, or fall was recaptured during the winter, indicating a probable turnover of birds between summer and winter.