I just set up feeders a couple weeks ago for the Sparrows and noticed the same thing.
Mom showed the babies the feeder right after basic flight training and they fly over to it and squawk for mom to come feed them and I watch mom come over and take chunks from the suet block and put it in the kids mouth lol..
Now though the parents are makeing them feed themselves,I noticed today that when mom came in to feed the chicks flocked over a squawking for food but mom chased them off, fairly aggressively at that. Now I see them feeding themselves.Oh nice @ninahaskin great shots all around =)