24 August 2011 - Morning Flight

There was but a small flight of northbound passerines this morning at Higbee Beach, mostly a mix of Yellow Warblers and American Redstarts with a few other species sprinkled in for flavor. These included Prothonotary Warbler, Worm-eating Warbler, Blue-winged Warbler, and Chestnut-sided Warbler, and another apparent hybrid Blue-winged x Golden-winged Warbler flew past as well (heading south).
There are two stereotypical phenotypes of Blue-winged x Golden-winged hybrids that have been named Brewster's Warbler and Lawrence's Warbler; while many of the increasing number of hybrids of this species pair "fit" Brewster's or Lawrence's quite nicely, there are other hybrids out there that can appear as anything on the spectrum between typical Blue-winged and Golden-winged Warblers. Indeed, plumage doesn't always reflect on the true ancestry of these birds: a recent study (including one here) demonstrated through DNA analysis that pure-looking Golden-winged Warblers often show genetic mixing with Blue-winged Warbler.
Since phenotypic analysis of any individual bird's genetic history is plagued by variation and uncertainty, it is usually a good idea to label birds like this (seen in the field and lacking a tissue sample) as "apparent" or "presumed" hybrids.

Here is a photo of the presumed hybrid "winged" warbler flying past at Higbee Beach this morning.