Sunday, April 30, 2017

Yellow-rumped Warbler

On 29 April 2017, Erika and I gave a banding demonstration at Big Woods State Park here in Rice County, Minnesota. The day began in the low 30s F. We felt our prospects for succuss were low. We were greeted, however, by swarms of Yellow-rumped Warblers. The campground hosts erected a dozen feeders laced with lard, peanut butter, and sugar.

In three hours, we banded 82 birds. fifty-one were Yellow-rumps. Many were males, told by their striking black and blue plumage. Others were dull and were probably females. The sex of a drab bird, however, can not be ascertained for certain. (These first two photos were actually taken the day previous at the University of Minnesota Landscape Arboretum.)

Among the males we caught two individuals with yellowish throats. These birds may be hybrids between eastern Yellow-rumped (Myrtle) and western Yellow-rumped (Audubon’s) warblers. Audubon’s Warblers’ throats are much brighter yellow; Myrtle Warblers’ throats ought to be white. Once before in Rice County, I banded similar warblers and I discussed hybridization elsewhere in this blog. The general consensus among ornithologists is that hybridization between these races is quite limited and many experts are lobbying to split them, once again, into two species. 

No comments:

Post a Comment