As they row themselves nimbly along, striking well out their broadly-webbed feet, they tilt their body tail upwards, and disappear with a single stroke. These birds are not, like the Divers, able to catch their prey by pursuing it under water; when they dive they seem to plunge more or less perpendicularly down to the bottom, and, after about a minute's absence, again make their appearance nearly upon the same spot from whence they vanished. As it is from the bottom of the water that they obtain their food, even those inhabiting fresh water have necessarily to dive to a considerable depth; whilst those that live in the sea must occasionally plunge still deeper, even to the depth of fifty or sixty fathoms--a fact of which it is easy to convince oneself by examining the contents of their stomachs. A few of them seem to prefer a vegetable diet, but the greater number live upon small bivalve shell-fish and other mollusca; they likewise eat worms, crustaceans, and fishes, while those that inhabit fresh water also feed upon aquatic insects. The booty thus procured from the bottom is also swallowed under water. The Diving Ducks, when employed in fishing for their food, only come to the surface to breathe. Their voice is totally different from that of the Swimming Ducks; instead of quacking they only screech. The manner of their breeding agrees pretty closely with that of ordinary Ducks; still, however, there are points of difference. They breed more in company with each other, and sometimes form regular settlements. Two females even of different species will occasionally lay their eggs in the same nest, sharing the duties of incubation and the charge of the young brood. Some individuals exhibit a sort of mania for brooding; they will slip into the nests of other birds, roll away the eggs, and take possession of them, or even tempt the nestlings away from their proper parents in order to take them under their own care. The eggs are rounder, the shells more closely-grained than those of the Common Ducks, but in other respects resemble them. Some Diving Ducks are valuable on account of the down with which they line their nests, others on account of the excellence of their flesh, but, generally speaking, the latter is rank and ill-flavoured. * * * * *