Like most other species belonging to the Passeres, the Cross-bills live in society, seldom leaving the woods, wherein they find fir-trees adapted to their support. They cannot be said to have any fixed residence, but are the gipsies of the feathered race; their home is anywhere and nowhere. It is by no means easy to discriminate between the different species of these birds, seeing that every extensive collection shows us many varieties, strongly resembling each other. We may, however, safely mention four different species belonging to Europe, and in the mountainous districts of Asia and America we also find about that number; all these, however, present not only the same general structure, but a similar colouring of the feathers. The plumage of the old male bird is of a beautiful vermilion or red-currant tint, while that of the young male is of either a reddish yellow, gold, greenish gold, or red chalk colour. The coat of the female is green, shaded into yellow or grey. The plumage of the birds before moulting is a light grey, streaked with a darker shade; the wings and tail-feathers are of a greyish black. The large head and strong beak, bulky feet, and short tail, make them appear very stout and clumsy, nevertheless they are really agile and rapid, flying quickly and lightly, hovering before they perch, climbing nimbly about among the branches, and are only awkward and out of place upon the ground. THE LARGE-BEAKED CROSS-BILL. The LARGE-BEAKED CROSS-BILL (_Loxia pityopsittacus_), the largest of all the Cross-bills with which we are acquainted, is from seven to seven and a half inches in length, and eleven and a half to twelve inches across the wings. The beak strongly resembles that of a parrot, and is very thick and high, bent into a crescent, each mandible terminating in a short hook. The prevailing colour in the plumage of the old male is either a dark or light vermilion; the wing and tail covers greyish black, edged with greyish red; the belly greyish white. The young male is recognised by its light-reddish tints, which upon the back are mingled with greenish yellow, and upon the rump with yellow. The female is dark grey on the upper part of the body, and the feathers have a more or less clearly defined edge of green or yellowish green. The under part of the body is light grey, the feathers being edged with greenish yellow; the wing and tail feathers are greyish black, dotted with greenish grey. THE PINE-TREE CROSS-BILL. The PINE-TREE CROSS-BILL (_Loxia curvirostra_), or FIR-PARROT, is a somewhat weaker and more slender bird than the preceding. Its length is from six to six and a half inches; its width across the wings ten and a half to eleven and a half inches. This species is distinguished from the foregoing by its longer and more delicate beak; the plumage of both birds being similarly coloured. THE BANDED CROSS-BILL.