Dear David and Simone,
Thanks for the info on the Green Parakeets. It was more like they spotted me. I stopped for gas and a noisy flock of fifty or so circled a few times and landed in a tree a few feet away.
This small bird (about sparrow sized) was foraging in rocks and cactus at Bosque. Looks close to a House Wren, but does a House Wren have this peachy underbelly?