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: <https://lh3.googleusercontent.com/-rDWh6ly3waU/Wu0RxdmKaMI/AAAAAAAAWaI/7Is6FnjmWtQS3iHFN797Jewz7cu_wSlbACLcBGAs/s1600/hybrid%2Bwarbler.png> 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 [email protected]. To post to this group, send email to [email protected]. 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.
