DIVING DUCKS.
These birds, described somewhat ambiguously by certain authorities as Sea Ducks, for all the species are by no means exclusively marine, yet all are expert divers, form a fairly well-defined and homogenous group, or sub-family, termed by systematists, Fuligulinæ. They are characterised by having a pendant lobe, or membrane, attached to the hind toe, and by their anteriorly scutellated tarsi. All the Ducks in this sub-family habitually dive for their food, and their movements in the water are remarkably agile. The sexes generally present considerable difference in colour, the males, as usual, being the most handsome and conspicuous. The young are always hatched covered with down, and soon able to accompany their parents on the water. The females have a single moult in autumn, but the males a partially double one. Diving Ducks, in fact all species in the family, in first plumage, closely resemble the old female, and acquire the adult plumage after the first autumn moult. We will deal first with the resident species, as being constant features in the bird life of the coast and sea.