There remains but one other bird of prey to mention here, and this is the sparrow-hawk. It may be easily recognized during flight by its short, rounded wings and long tail. The female, which is much larger than her mate, has the under parts distinctly barred. The breast of the male is similarly marked, but the bars, being of a pale rufous, or rust-colour, and much narrower, are less conspicuous. It has a very rapid and gliding flight, just above the ground, or along hedgerows, which it scours in its search for small birds. There may be many who will fare forth to find the harrier on the wing. If they succeed they will indeed be fortunate. But there is one bird that most certainly will be seen in the "harrier-country," and that is the heron. There can be no mistaking him. He may be found, a large, grey bird, standing contemplative, knee-deep by the river's margin, or in some ditch, awaiting the moment to strike at some unwary fish, frog, or water-vole. The moment he discovers that he is being watched he will be on the move. He rises heavily, almost awkwardly, with flapping wings and outstretched neck: his legs dangling down. But no sooner is he well on the way than he hauls in his neck till the head is drawn close to the body, and straightens out his legs till they extend behind him like a pair of streamers. Henceforth his flight is easy and graceful enough. This is the bird which was so much prized in the old days of "hawking." The invention of the gun ended this most fascinating form of sport. Let us turn now, for a little while, from moor and wood and fen, to the sea-shore, and, for choice, to a rock-bound coast with towering cliffs. Here you will find a number of species which will never be found inland. They love the sea, whether it be shimmering in the sun of a blazing June day, smooth as a millpond, or in a fury of thundering billows, lashed by a roaring gale in bleak December. The bottle-green shag is one of these. You cannot mistake him. Perched on a rock he sits upright, and, in the spring, wears a crest upon his head. On the water he floats with the body well down, and every few moments disappears with a spring into the depths, for his never-ending meal of fish and crabs. His flight, just above the water, is strong and rapid. His cousin, the cormorant, is a conspicuously larger bird, with a bronze-coloured plumage. In the breeding season his head has a hoary appearance, due to the presence of numerous filamentous feathers, known as "filoplumes"; while the throat is white, and there is a large white patch on the thigh. He has a habit, after a full meal, of sitting on some convenient perch with wings spread wide open and open-mouthed, apparently as an aid to digestion. But he is by no means so wedded to the sea as the shag. Rivers and inland waters will serve him as well as the sea. [Illustration: