Page:Natural History, Birds.djvu/331

318 sent in considerable quantities to the markets at Norwich and Lynn. . . The young birds leave the nest as soon as hatched, and take to the water. When they can fly well, the old ones depart with them, and by the middle of July they all leave Scoulton. We were a little surprised at seeing some of these Gulls alight and sit upon some low bushy willows which grew on the island. No other than the Brown-headed Gull breeds at this mere; a few of them breed also in many of the marshes contiguous to the sea-coast of Norfolk."

The most characteristic mark of this the last Family of Birds, is, that the hind-toe, which can be brought partially round to point forward, is united to the others by a connecting membrane, so that the whole four toes are webbed. Notwithstanding this structure, which seems to fit them more completely for an aquatic life, most of these birds do not swim or dive at all, but on the other hand, they perch much on trees. They are all good fliers, and some, from the extreme expanse of their wings, have extraordinary powers of flight. They spend a great deal of time upon the wing, some soaring far out over the ocean, or mounting to a most sublime elevation, others beating over a limited space, till the appearance of a fish beneath them arrests their attention, when they plunge down upon it, and instantly rise again into the air.