Hello, Birders.
Early this Thursday morning, May 30th, I saw a beautiful second-year female Northern Parula hanging out with a flock of Yellow-rumped Warblers. The warbler flock was in the cottonwoods at the northwest corner of Waneka Lake, which is basically the southwest corner of Greenlee Preserve. The parula was exceedingly, almost ridiculously, cooperative, just hanging in plain view at close range for a goodly 15 minutes. Find the huge, utterly dead cottonwood, then look west; that's where the birds were.
Other than the slam-dunk parula, the rest of my time at Greenlee was a wonderful reminder of just how fascinatingly indeterminate is the experience of birding in Colorado in May. For example:
1. I briefly saw what I coulda sworn was a dull female Mourning Warbler, and I audio-recorded its chip notes; review of the sound spectrograms indicates something frankly in between the chip notes of Mourning and MacGillivray's. However, the bird was calling softly, and I wasn't terribly close when I made the recordings; so I consider the acoustic evidence to be inconclusive.
1, cont'd. Mourning and MacGillivray's warblers frequently hybridize where their ranges overlap, and I would imagine that we get a number of hybrids through eastern Colorado, a la Myrtle and Audubon's warblers. In a recent study from the zone of overlap, more than 1/3 of all "MacMourning" Warblers were shown by genetic analysis to be hybrids; particularly vexing is that birds resembling a "pure" parental type can be significantly introgressed. Paul Hess has a nice summary, with some "troubling" photos (a bird looks like one parent, but it's really the other), here: http://www.aba.org/birding/v42n3p30.pdf
2. Heard-only empids. One was of the Dusky/Least/Willow/Gray variety. I'd lean Willow. I called it "spuh." Another said "pip," loudly so. Alder? I'll try again late this afternoon. For now, it's another "spuh."
3. Pheucticus grosbeaks. One looked like a nice male Black-headed, but who knows. The other seemed to have hybrid traits, but who knows. By the way, Pheucticus has four syllables. It's pronounced fee-UCK-tuh-CUSS. And Picoides is pronounced like this: PIE-co-EYE-deeze. And Cypseloides is sip-suh-low-EYE-deeze. You know, the next time you find yourself at a cocktail party...
4. Warbling Vireo. It was singing a fair bit, weirdly so. Couldn't tell if it was an Eastern or a Western. Happens. And then there's the problem of Westerns than sing Eastern songs, and vice versa.
5. Audubon's/Myrtle Warbler. One was intermediate or a hybrid, or both. Dunno. The other Yellow-rumps were unambiguous Audubon's. Or were they? Genes...
A few birds out there presented fewer ontological challenges, among them drake Wood Ducks, adult male Yellow-headed Blackbirds, and an adult Bald Eagle.
Still lots of stuff moving through Colorado, as many others are noting. Thanks for all the great reports!
Ted Floyd
tedfloyd57@hotmail.com
Lafayette, Boulder County, Colorado
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