About 500 terns swirled and dove into the Cape May rips, and after a second or two of appreciating the frenzy for the spectacle it was, I set about doing what birders do: identifying the members of the flock. How to go about doing that with a maelstrom of terns 500 yards off the beach is a fit subject for another column, and will be someday, but suffice it for now to say I discerned that about 400 of the terns were Forster’s, 75 were Commons, 25 were Leasts, and if there was anything rarer than that out there I couldn’t find it.
Forster’s Tern in breeding plumage
Now what?
I checked the beach, discovering a few Sanderlings and a lingering, non-breeding Black-bellied Plover. The ocean away from the rips and their accompanying tern frenzy seemed barren, with just a few scattered gulls wandering past.
Had I “used up” the birding for that place and moment? Hardly, though I believed I’d identified everything in sight and reached the point at which many birders, including me sometimes, feel it’s time to move on to a new location.
Instead, I turned my scope back to the terns. I picked out an individual Forster’s, and stayed with it, with several things on my mind:
How can I get better at identifying this bird?
You can ask that question about any species, even “easy” ones like adult Bald Eagles or Painted Buntings. Terns, however, are especially ripe subjects, since they are so similar and often seen in the distance or in bad light conditions. Early ornithologists, including Audubon, did not even realize that Common and Forster’s Terns were two different species. I “work” on terns all the time, and for a while this day I studied the shape of the Forster’s where its head joined the body, deciding that no matter the angle the bird never looked small-headed, the way Common Terns sometimes do. The head of my Forster’s seemed to always match the circumference of the body, or nearly so.
What is this bird doing now? How is it going about its business?
I learned right away that this tern was not flying around randomly looking into the water. When I picked it up the tern was in the middle of the flock, and it worked its way into the wind to the left (east) side of the rips, then dropped out, circled around, and re-joined the flock at the right side. After three repeats this qualified as a pattern, broken only by the occasional (unsuccessful) dives for fish.
Why is this bird doing what it’s doing?
Well, duh - in this case it was trying to catch a fish. But why then and there? With a strong outgoing tide, I knew fish concentrate where the bottom is uneven and the water turbulent - the rips are a prime spot for human fishermen for this reason, as well as for birds. What did it want the fish for? Well, duh - or maybe not. Because when the Forster’s Tern finally caught a fish, it left the frenzy with it and came to shore, passing over my head in the process. The date, June 3rd, suggested it probably did not yet have young to feed. The fish was meant for its mate, either as a courtship gift or for sustenance as it incubated their eggs.
With “my” bird out of view, I turned back to the flock, this time picking out a Common Tern. I had several things on my mind. . .