There were only a few terns, such as the one below, which I think is a Royal Tern. It "terns" out, most were black skimmers.
In the picture of the yawning bird below, you can see how much longer the lower bill of the skimmer is than the top. This allows them to fly just above the surface of the water and skim for small fish and crustaceans. Interestingly, I read that the bills are of equal length as hatchlings but grow disproportionately as juveniles.
We were careful to keep our distance and walked up on the wide shore so as not to disturb them. We were down the beach a ways when we heard their wings. A mother thought nothing of letting her two children run at them. You can see that the gulls were less impressed.