Piratic jaegers, Stercorarius pomarinus, Stercorarius parasiticus, apparently never trouble these Eastham birds. I have seen but one jaeger on this beach, and that a solitary bird who chanced to pass the house one morning last September. Cape Cod neighbours, however, tell me that jaegers are numerous in the bay, and that they harry the terns who fish the shoals off Billingsgate.
Almost every day, in the full heat of noontide, I go down to the lower beach and lie down for a while on the hot sand, an arm over my eyes. The other day, in a spirit of fun, I raised my arm toward a passing tern—the returning birds fly scarce thirty feet above the beach—and to my amusement the creature paused, sank, and hovered above me for a few seconds scarce ten feet from my hand. I saw then that its under plumage, instead of being white, was a lovely faint rose; I had halted a roseate tern, Sterna dougalli. I wriggled my fingers; the bird responded with a cry in which I read bewildered indignation; then on it flew, and the incident ended.
This year a number of laughing gulls, Larus atricilla, accompany the terns fishing, the dozen or so gulls keeping to themselves while flying with their neighbours.
The most interesting adventure with birds I have had this summer I had with a flock of least terns, Sterna antillarum. It came to pass that early one morning in June, as I happened to be passing big dune, a covey of small terns unexpectedly sailed out at me and hovered about me, scolding and complaining. To my great delight, I saw that they were least terns or “tit gulls,” rare creatures on our coast, and perhaps the prettiest and most graceful of summer’s ocean birds. A miniature tern, the “leastie,” scarce larger than a swallow, and you may know him by the lighter grey of his plumage, his bright lemon-yellow bill, and his delicate orange-yellow feet.
The birds were nesting at the foot of big dune, and I had disturbed their peace. In the splendour of morning they hung above me, now uttering a single alarmed cheep, now a series of staccato cries.
The Tern Chick
I walked over to the nests.
The nest of such a beach bird is a singular affair. It is but a depression, and sometimes scarcely that, in the open, shelterless beach. “Nest building on the open sand,” says Mr. Forbush, “is but the work of a moment. The bird alights, crouches slightly, and works its little feet so rapidly that the motion seems a mere blur, while the sand flies out in every direction as the creature pivots about. The tern then settles lower and smooths the cavity by turning and working and moving its body from side to side.”
I have mislaid the scrap of paper on which I jotted down the number of nests I found that morning, but I think I counted twenty to twenty-five. There were eggs in every nest, in some two, in others three, in one case and one only, four. To describe the coloration of the shells is difficult, for there was a deal of variation, but perhaps I can give some idea of their appearance by saying that they were beach-coloured with overtones of bluish green, and speckled with browns and violet-browns and lavenders. What interested me most, however, was not the eggs, but the manner in which the birds had decorated their nests with pebbles and bits of shell. Here and there along the beach, the “leasties” had picked up flat bits of sea shell about the size of a finger nail, and with these bits they had lined the bowl of their nests, setting the flat pieces in flat, like parts of a mosaic.