This is the male brown-headed cowbird. Lots of people hate these birds because they lay their eggs in other birds' nests and then just go their merry way, leaving the often much smaller bird to raise enormous interlopers that often get more than their fair share of the food and attention. The explanation for this practice is apparently that back in the day these birds followed the herds of bison across the plains and were thus unable to stay in one place to raise their young. So - they came up with a strategy.
I rather like them. I like the way the males look, and they have a fabulous set of noises that they make, one of which sounds like water dropping into a pool.
The extra shows his mate, the rather drab looking bird below him. I wonder whose nests she's laid her eggs in...