Introduction

An imperilled Neotropical migrant, the Golden-winged Warbler is a small but stunningly beautiful songbird of the northeastern and north-central U.S. and southern Ontario. Bright patches of yellow on the crown and wings punctuate its elegant soft gray colored plumage, as do the bold chickadee-like patches of black on the throat and face.

Although it increased in abundance and expanded its distribution for more than a century, the Golden-winged Warbler is now declining in many areas and has disappeared from previously occupied regions. It appears to thrive initially with appearance of shrubby, early-succession fields that follow logging, fire, or abandoned farmlands. Local declines then correlate with advancing succession and reforestation and also with the invasive range expansion of its sister species, the Blue-winged Warbler (Vermivora pinus). Other possible causes of the population decline are loss of wintering habitat, especially forest edge and open woodland in Central and northern South America, nest parasitism by the Brown-headed Cowbird (Molothrus ater), and hybridization with Blue-winged Warblers.

Golden-winged and Blue-winged warblers interbreed and produce fertile hybrids, often called “Brewster’s” and “Lawrence’s” warblers.

The mechanisms by which hybridization favors Blue-winged Warblers require further study. Song recognition and function in these warblers have been studied extensively, especially in relation to pair formation and speciation.