This male Cardinal was feeding this baby. This sure doesn't look like a baby cardinal. The other baby that I couldn't manage to capture was a female cardinal.

Here is what I found out about Cowbirds. Upon choosing a nest, she removes one egg of the host's clutch, and deposits one of her own in its place. Cowbirds lay eggs in the nests of more than 200 other species, most smaller than themselves. Some host species eject the unwanted egg, others lay down a new nest lining over it, but most rear the young cowbird as one of their own. The young cowbird grows quickly at the expense of the young of the host, pushing them out of the nest or taking most of the food.