Woodpeckers seem to feed their babies longer than many other birds. In fact, the Downy in the following photograph (taken last month) is actually larger than the parent. She had been brought to the tree to try to feed herself. Several times she tried to summon the courage to fly to the suet but each time she failed. Finally she started screaming with frustration and the mother obliged once more and gave her some breakfast.
It seems to us that bird parents are rather like human parents. Some of them know exactly when to turn loose but some of them continue to feed the young long after it appears they could manage on their own. We have observed some birds coming to the feeders and eating; then flying to the trees screaming for their parents who will come feed them again.