Tuesday, September 10, 2013

Golden-winged Warbler

On Sunday I banded this Golden-winged Warbler. This warbler is so beautiful that I can not resist sharing this image with you, despite having done so a few times in the past. Indeed, I took a very similar photograph last spring. Previously I have discussed the possibility that there is good reason that this warbler looks somewhat like a Black-capped Chickadee. I have also described the genetics of this species’ hybridization with Blue-winged Warblers.

Golden-winged Warblers have been declining for the last 40 years at a rate of 2.8% per year. The species no longer breeds in part or all of Georgia, South Carolina, Virginia, Massachusetts, Connecticut, Rhode Island, Vermont, New Hampshire, Indiana, Illinois, and Ohio; the species is listed as threatened in Canada and a “species of management concern” in the United States (Confer et al. 2001). On the bright side, Golden-winged Warblers are increasing and spreading northwest across Canada.

What’s happening? The secondary habitat in which they breed is disappearing in the East, where old fields are once again becoming forests and where people destroy wetlands. Loss of habitat in their wintering grounds may also work against the species. Golden-winged and Blue-winged warblers also hybridize. The hybrids apparently have reduced fitness, and they drop out of the populations within 50 years of initial contact; they are replaced by Blue-winged Warblers. Furthermore, Golden-winged Warblers may be particularly prone to parasitism by Brown-headed Cowbirds. Remedies suggested to combat this decline include burning nesting areas to keep fields in a state of early succession, planting aspen in the northern parts of the range, control of cowbirds, and even killing Blue-winged Warblers in areas of overlap (Handbook of Birds of the World Alive).

2 comments:

  1. I love your shots of the birds looking right at the camera. A view field guides rarely get.

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