The British paper, the Daily Mail, has published a news story and photographs featuring a Least Tern, its chick, and a rather large baitfish. This illustrates perfectly one of the reasons that I, personally, enjoy birds so much: They’re really funny.
In all seriousness, though, terns and skimmers feed their chicks whole prey, which they capture and bring back to the colony. You won’t see them regurgitating pre-digested food to chicks. Therefore, tern and skimmer parents bring increasingly larger fish back to the colony as their chicks grow and can eat larger and larger fish. Sometimes they over-reach–or the fish is too spiny–and the chick rejects the meal, but usually they manage. Skimmers will actually “pre-chew” fish by chomping on it in their bills in order to help their chicks out. If you are at the colony early in the morning, be on the lookout for feedings. It’s fun to watch.