I have been filming a American Robins nest with chicks. I discoved the nest about three days ago. I have noticed that the mother or father will fly in with a worm or some other grub and feed it to the waiting chicks. He/she will apparently wait around for a couple of minutes and before leaving the nest he/she will take something from one of the chicks and seem to swallow whatever it is. I have a picture of it below. Is this some kind of waist or what. Can anyone help? Thanks ahead of time.
Great document image! That is the parent removing the fecal sac, which is a thin membrane containing the young chick's waste. Many birds do this to avoid the nest being overflowed with waste...as I'm sure you've witnessed, these young ones have a voracious appetite!! I'm not convinced that the parent swallowed it though. Most likely flew off with it and dropped it a good ways away (to avoid giving clues to potential predators). Here's a Great-crested Flycatcher about to fly off with one: