Page:The birds of Tierra del Fuego - Richard Crawshay.djvu/269

Rh were generally distributed over the entire surface, usually more numerous and dense at the larger end, occasionally forming a massive ring.

Capt. King and Darwin do not mention this Tern.

Capt. Abbott says it arrives in the Falkland Islands at the end of July, and breeds in communities on the sea beach, but also occasionally inland, in pairs, laying two, sometimes three eggs in each nest. It disappears about the end of March.

Durnford met with, a very remarkable colony on Tombo Point. Central Patagonia, which he thus describes:—"I was prepared to see a considerable quantity of birds; but the number that met my eyes fairly staggered me. The nests cover an area about 150 yards square. Allowing three nests and five eggs for every square yard (a very moderate computation, it being difficult to walk without treading on the eggs), we arrive at the extraordinary number of 67,000 nests, 135,000 birds, and 112,500 eggs; and, wonderful as these figures may appear. I feel sure that I have rather understated than overstated the numbers. The nests were mere hollows in the fine gravel or shingle, and contained one, two, and sometimes three eggs. The latter generally have the appearance of the eggs of the Sandwich Tern, though of course smaller, and out of many hundreds I did not see two alike."

The three eggs I have represent about the extremes of variation in the colony in Useless Bay. A pair from the same nest are of elongate ovate form, with pale greenish-blue ground, and somewhat sparse markings over the entire surface, tending to become more numerous at the larger end. They measure 1'9 by 1.25 and 1.9 by 1.3 inches. The third egg is short ovate, with ochre-brown ground and a well defined massive ring round the larger end; it measures 1.75 by 1.3 inches. Of the latter type of egg there was but one pair in the colony.