[cobirds] Let's document Myrtle x Audubon's Warblers in Colorado

Hey, all. Earlier this Friday evening, May 4, I saw a couple of Myrtle x Audubon's Warblers at the University of Colorado South Campus near Tantra Road, Boulder County. Which got me to thinking about something...

Away from the breeding grounds, Myrtle and Audubon's Warblers co-occur across a huge swath of western North America, easily a million square miles. Yet The Sibley Guide informs us that hybrids are rarely detected away from the breeding grounds. I have no reason to doubt the overall accuracy of that statement, but I also note that, at least here in eastern Boulder County, hybrids (or intergrades, if you prefer) are legion.

Here's the deal. Even though Myrtles and Audubon's spread out across a vast region when they're not breeding, that's not necessarily the case for their hybrids. By analogy, consider the enormous winter range of the Dark-eyed Junco vs. the quite limited range in winter of White-winged Junco. (White-winged Junco in winter occurs chiefly in the ponderosa pine belt of the Colorado Front Range.) I wonder if Myrtle x Audubon's hybrids are similarly range-restricted. For what it's worth, I never knowingly saw a Myrtle x Audubon's hybrid in all my years of looking at Myrtle and Audubon's warblers in New Mexico (1992-1994) and Nevada (1999-2002).

It would be cool if we could say with some precision where Myrtle x Audubon's warblers go when they're off the breeding grounds. Definitely here in eastern Boulder County! But how much more extensively?

Here's a photo of one of the hybrids I saw this evening:

What to do? Easy! Put it all on eBird.

Ted Floyd

Lafayette, Boulder County

--
You received this message because you are subscribed to the Google Groups "Colorado Birds" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cobirds+unsubscribe@googlegroups.com.
To post to this group, send email to cobirds@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/c613b420-2af0-4581-8e4b-9c0fa54b9000%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.