Influence of habitat on the occurrence of the endemic Barbuda warbler (Setophaga subita) and resident yellow Warbler (S. petechia)

Abstract

The Barbuda Warbler (Setophaga subita), endemic to Barbuda, Lesser Antilles, and resident Yellow Warbler (S. petechia) are known to co-exist in at least some areas on Barbuda; but since little else is known of these species’ ecology on the island, much more groundwork is needed. This study explored (i) spatial and temporal distribution; (ii) seasonal patterns of breeding and moult; and (iii) patterns of habitat use, of both warbler species on Barbuda. Gathering these data required extensive island surveys of both species conducted over four month-long field trips. Mist-netting and colour-banding target warbler species revealed information on demography, breeding and dispersal. The distribution of each species was found to be non-random. Point-count data analysis revealed that the Barbuda and the larger Yellow Warbler used slightly different physical resources; Barbuda Warblers occur in negative association with Yellow Warblers, but Yellow Warbler distribution was not found to be influenced by Barbuda Warblers. Along with their respective processes of habitat selection, interspecific interactions may contribute to their ecological separation. Both species were found to breed almost at the same time, in months of May and June, a pattern consistent with most North American Passerines.