Being regularly clipped all around each year by the cows, as a hedge with shears, they are often of a perfect conical or pyramidal form, from one to four feet high, and more or less sharp, as if trimmed by the gardener's art. In the pastures on Nobscot Hill and its spurs they make fine dark shadows when the sun is low. They are also an excellent covert from hawks for many small birds that roost and build in them. Whole flocks perch in them at night, and I have seen three robins' nests in one which was six feet in diameter.