nearly over, and not only does this when perching, but flies aloft like the adult bird in the spring-time, and soars for a long time, singing continually. Titmice all sing when still quite young, but more especially the large crested titmouse and the marsh titmouse; the notes of the young marsh titmouse are precisely similar to those with which in spring the adult bird sings to his mate; and as regards the crested titmouse, in October 1821, I observed a young male bird making advances of a most marked character to a young hen, whilst the hen drooped its wings and spread out its tail--in short, these two young birds were behaving exactly as do the full-grown birds before pairing in the spring. The young cock starling conducts itself precisely as if it wished to pair. At the beginning of September, as soon as moulting is completed, this bird returns to its birthplace, apparently in order to take possession of the nest. It perches on the tree-top, just like the full-grown bird in March, and sings almost for the whole morning. While still perching, it flaps its wings, quarrels with and chases other young starlings; sometimes it even creeps into the hollow tree or other hiding-place containing the nest in which it was hatched. The yellow wagtail sings while still in its youthful plumage, and the young birds chase one another about while in this condition; during and immediately after the first moulting, these birds produce peculiar trilling notes, identical with those with which in April the cock bird salutes his mate, and they may also be seen in the remarkable fluttering flight characteristic of many birds in the pairing season. The grey wood wren begins to sing before the first moulting, but sings more powerfully during and after moulting, right on into the month of October, singing like a full-grown bird. At the same time this bird twists the body from side to side, and moves the tail to and fro; it quarrels also with birds of its own species, and quarrels, too, with other birds, sometimes with birds as much as four times its own size. In August and September young mountain fowl and heath fowl utter love calls to each other, not, indeed, so loudly as those of the adult birds, nor in association with the characteristic movements of the body made by these latter in the spring-time, but still unmistakable love calls.... According to Hudson, many kinds of American woodpecker carry on a kind of duet, and they practise this artistic performance from the very earliest youth. On meeting, the male and female, standing close together, and facing each other, utter their clear ringing concert, one emitting loud single measured notes, while the notes of its fellow are rapid, rhythmical triplets; their voices have a joyous character, and seem to accord, thus producing a kind of harmony. This manner of singing is perhaps most perfect in the oven-bird (_Furnarius_), and it is very curious that the