In many respects Grebes are remarkable birds. They form so well defined a group that no other known bird can possibly be confused with them, their characteristics being absolutely unique among the class Aves. The most noticeable external features of a Grebe are its relatively short body, laterally compressed tarsi, lobed feet, rudimentary and functionless tail, and dense compact plumage of a peculiar silky texture. The twenty or so species of Grebes are grouped into a single family, called Podicipedidæ, of which the genus _Podiceps_ (or more correctly _Podicipes_) contains the greater number. The Grebes are almost cosmopolitan. Five well-marked species are found in Europe, all of which, being visitants or regular residents, are included in the British avifauna. In the colours of their plumage the Grebes are not very remarkable, with the exception of the crests or tippets assumed by some species during the nuptial period: plain browns predominate on the upper surface; the underparts are almost always glossy white. The Grebes fly well; dive with great dexterity, but their movements on the ground are not graceful. The young are hatched covered with close down, and able to swim at once. The Grebes have a complete moult in autumn, and assume their nuptial ornaments in spring. The quill feathers are moulted so rapidly that for some little time the birds are unable to fly, as is the case with the Geese and some others. It is only during the winter months that the Grebes become pelagic or marine in their habits, and even some species are much less addicted to a sea life than others. We will now proceed briefly to glance at the British species. GREAT CRESTED GREBE.