Hey, I just shot about 40 feeding images; the "parent" is a little male lesser goldfinch and the giant baby is about 3 times his size. I know that's weird, and I am not sure what kind of baby bird is that. Soon I remembered that you talked about the step-parent's feeding stuff... here you go! The giant baby is this brown-headed cowbird AGAIN!
I am packing for the trip, so I have not yet arranged the pictures. ^__^
Have a nice weekend.