A Reassessment of the Status of Golden-winged and Blue-winged Warblers in the Hudson Highlands of Southern New York

Abstract

Populations of Golden-winged Warblers (Vermivora chrysoptera) and Blue-winged Warblers (V. pinus) have coexisted in the Hudson Highlands for a century. Previous researchers in our study area suggested this unusual coexistence might be due to a low frequency of hybrids. However, during the 1998–1999 breeding season we found that 10% of the males were hybrids, a value similar to many studies elsewhere. We observed that hybrid males ceased singing and other conspicuous behaviors early in the breeding season. Pair formation and nesting by hybrids appeared to be rare, perhaps because of the reduced vigor of their displays. Most of the fieldwork by previous researchers in this area was conducted after the date when hybrids cease singing, which may account for prior reports of the absence of hybrids.