Tuesday, August 19, 2014

Mexican Jay

Erika and I first visited Big Bend National Park 40 years ago when we were heading towards graduate school.As poor students, all we could afford was to spend the night tenting in an overflow campground next to airstream vans running their air conditioners. In February, we stayed at the park lodge in the Chisos Basin. Signs warned not to feed the wildlife, but we were delighted that this Mexican Jay flew up to see if we would break this commandment. Clearly other visitors ignored the sign.
I have previously discussed the amazing social organization of Mexican Jays. The species forms three populations, one in the eastern Sierra Madre Oriental (and ranging north just past the Texas border), one in the western Sierra Madre Occidental (ranging into Arizona and New Mexico), and a third in central Mexico. Recent molecular studies suggest that these populations should be split into two or three distinct species. Arizona and New Mexico birds would be called Mexican Jays, while those in Texas would be Couch’s Jays. The populations are slightly differently plumaged—Texas birds are slightly more blue on the chest—and the two “species” have slightly different vocalizations. Finally, the birds of central Mexico may be a third species, but the data for that split is more ambiguous—these birds might remain as a race of the Couch’s Jay (McCormack and Brown 2008).

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