Autumn monitoring of resident avifauna on Guana Island, British Virgin Islands

Abstract

Although the Caribbean region is considered a biodiversity hotspot and a priority for ecological conservation efforts, little information exists on population trends of West Indian landbirds. We combined avian survey data collected from three studies spanning a 16-year period on a small island with a minimal human presence in the British Virgin Islands. Although abundances varied among surveys, the same species were detected with rare exceptions. Despite stability in species composition, the resident landbirds were variable in their individual detectabilities. Survey detections relatively mirrored net captures for some species, but are quite different for others. We suspect that this is likely due to differences in detectability due to species-specific behaviors mediated by environmental conditions, such as rainfall, during the month or months prior to our surveys. It is difficult to assess the influence of timing or amount of precipitation on bird detections rates among our surveys due to a lack of consistent collection of location-specific weather data in the British Virgin Islands. Our study suggests monitoring efforts conducted in concert with collection of site-specific climate data would facilitate improved interpretation of survey data and a better understanding of avian species response to climate mediated changes.