Black-crested
Titmouse, Baeolophus atricristatus
The Black-crested Titmouse, found in Southern Texas, was formerly considered a subspecies of the familiar Tufted Titmouse, found in much of North America.
These two birds look like they might be a pair, with the male about to offer a seed to the female as a courting gesture. Actually, they were two males who had been battling over primary access to a nearby feeder, and the one on the left had just won the battle.