Final posting (two images) of the Eastern Kingbirds. In addition to feeding the young Mom/Dad also have to do chores. Whilst there are no diapers to change, they nevertheless, work hard at keeping the nest tidy and clean. Each time after bringing grub for the kids, they check the nest for fecal sacks, which, if there are any, they promptly remove. Sealed fecal sacks, filled with excrement, are deposited by the young directly into the nest. Their prompt and efficient removal by the parents ensures that the nest remains relatively clean. The adults simply pick up the sacks and deposit them somewhere else.
In the top image one of the adults can be seen to pick up a fecal sack after having delivered a bug. This sack had just been excreted by one of the young who's behind is still visible.

Several fecal sacks have been deposited on top of a concrete post by the adults. I'm not sure why they would pile them up in one location rather than just drop them to the ground once they are away from the nest.
This is the last posting of the Kingbirds and their young. Thank you all for your kind comments throughout the various series posted.