The Black Duck is a very wary creature, exceedingly difficult of approach. They are found in great numbers, except when congregated on salt water, five to ten being an average flock started from pond and feeding ground. During very severe winters, says Hallock, when every sheet of water is bound in with a thick covering of ice, the Black Ducks are driven to warm spring holes where the water never freezes. The approach of evening drives the Ducks from the bay or sound, where they have been sitting during the day, and they seek these open inland spots for food and shelter. Brush-houses are constructed of sedge, cedar boughs, etc., at the mouths of fresh water rivers and creeks, in places where the marsh land is low and intersected by branches of the main stream. Here the Ducks come to feed at night and are taken by hunters who are concealed in the bushes. These houses are left standing, however, and the wary Ducks soon avoid entirely this locality, and feed elsewhere. The brush-house building on feeding grounds cannot be too severely condemned. Hallock observes that of all the birds which during spring and fall traverse our country probably none equal these Ducks in point of size, numbers and economic value. The group is confined neither to the sea coast, nor to the interior, but is spread out over the whole breadth of the continent, in summer extending its migrations to the furthest north, and in winter proceeding only so far south as it is forced to by the freezing of the waters of its northern home. THE STORMY PETREL. "The Stormy Petrel, mamma, is a very interesting bird. I should like very much to be in a ship and see him walking on the water, wouldn't you?" Mamma, who thought of the apostle St. Peter, shook her head. "You must be mistaken, Bobbie," said she. "I never heard of a bird that could walk on the water." "Well, that's what my magazine says," replied Bobbie, "and I am sure BIRDS ought to know. Listen!" and Bobbie, stopping to spell a word now and then, and to ask the meaning of many, managed to inform his mother what the _Stormy Petrel_ had to say about himself. "Though I am the smallest of the web-footed birds I am a great traveler," read Bobbie. "Everywhere over the entire surface of the watery globe you will find members of my order; far north in the Arctic seas and away down in the Southern oceans. We love the sea, and the food which is thrown up by the waves. Anything oily or greasy we particularly like. No matter how stormy the weather, nor how high the billows roll, you will see us little fellows, with outstretched wings, sweeping along in the hollow trough of the sea. From one side of a ship to the other, now far ahead, then a great way behind, catching up easily with the ship though making ten knots an hour." "What is a knot, mamma?" querried Bobbie.