Here's a couple of photos of the female Mountain Bluebird at Santa Ana NWR. The long winged profile (compared to Eastern Bluebird) is evident here, as is the sky-blue rump and tail. This is the first winter with Mountain Bluebirds in Hidalgo County since I moved here in 2006. The first birds found were a pair in San Juan that did not remain. There are several in western Hidalgo County as well.