The number of ocean birds breeding on these tiny island-paradises is amazing. Minute Mast Head Island is a place free of all pests--no flies, no mosquitoes, no ticks, no snakes, nor prickly plants, but a deep shady forest of giant _Pisonia_ trees, sometimes covered with creepers and lianas, and fringed with pretty flowering shrubs, fig trees, and long green grass, and surrounded, above spring-tide level, by a fringe of graceful Horse-tail Sheoaks (Casuarinas). We calculated that over 100,000 birds bred annually on this 100-acre sandbank, no point of which rose 10 feet above spring-tide level. The graceful White-capped Noddies already mentioned nested high and low on the trees and shrubs. Petrels in thousands burrowed in the sand under the giant _Pisonias_, which are so thickly foliaged that not enough light penetrates to enable undergrowth to flourish, so the sand was practically bare in the centre of the island. Reef Herons nested low on spreading branches or interlacing roots. Silver Gulls and Oyster-catchers nested on the ground, within about a yard of the spring-tide mark; Doves, Silver-eyes, Bell-Magpies (_Streperas_), Caterpillar-eaters, Kingfishers, and other land birds nested in the trees, while the White-bellied Sea-Eagle (almost a fac-simile of the Bald Eagle of America) had his nest overlooking all, on the highest tree on the island. The Frigate Birds were not nesting on Mast Head Island, but they roosted each night in the tall Sheoaks at the water's edge. It was a treat, in the late afternoon, to see these glorious birds winding up their invisible staircase into the vast void of upper air. Gloriously and calmly they sailed up and up, until the merest speck only could be seen. Of corals, turtles, and other marvels we may not speak here. The migrating wading-birds had just reached the island after their long journey from Siberian Tundras. Some were so poor that we caught Sandpipers by hand. Flocks of Turnstone, Golden Plover, Godwits, Curlew, and other wading-birds were there, possibly only resting before continuing their journey to the South. It was indeed a privilege to live on such a spot for nine days and to see Nature in some of her most interesting phases. The two Australian Seagulls illustrate the "law of representatives" so often referred to by Gould. It is strange how often a closely similar representative of a Northern bird is found in Australia. Thus the big Pacific Gull is the representative of the large Gull of Europe, though its peculiar deepened and orange-colored bill is distinctive. It does not gain its beautiful white and black plumage until it is three or more years old, being brown in the first year, and brown and white in the second year.