The nest is built during the last half of April in a holly or yew, or other dense, dark bush or tree, or in a thick hedge. It is unlike the nest of any other finch, being outwardly a platform-shaped structure made of interwoven twigs, with a cup-shaped nest in the centre, formed of fine rootlets, the rim of the cup projecting above the platform it is built on. The eggs are four to six, greenish blue in ground-colour, spotted and sometimes streaked with dark purplish brown, and blotched with pinkish brown. Bullfinches pair for life, and at all seasons of the year male and female are seen together; if any young are reared, they usually remain in company with the parent birds during the autumn and winter months. * * * * * Nearly allied to the common bullfinch are two beautiful birds which have a place in our list of species. One of these is the rosy bullfinch (_Carpodacus erythrinus_), of which two or three stragglers have been found in England; it breeds in Finland, and is found throughout the Russian Empire. The other is the pine grossbeak (_Pinicola_ (_enucleator_), also a rare straggler to Britain from the north of Europe. Crossbill. Loxia curvirostra. [Illustration: FIG. 50.--CROSSBILL. ¼ natural size.] Wing and tail feathers brown; all other parts green, yellow, orange, and tile-red, according to age and sex. Red is the colour of the adult male in a state of nature, and yellow in captivity. Length, six inches and a half. * * * * * The crossbills differ from all other birds in the extraordinary form of the parrot-like bill. In other birds, whatever the shape of the bill may be, straight or curved, or broad and flat, or conical, or hooked, the two mandibles correspond, and fit when closed like box and lid. In this bird both mandibles have prolonged curved points, and cross each other, much as the two forefingers of our hands cross when the fingers are loosely linked together. A full description of this form of beak and its use as a seed-extractor, together with an admirably written history of the common crossbill, is contained in the second volume of Yarrell’s great work (fourth edition). The crossbill is also remarkable on account of the changes of colour it undergoes and of the brightness of its colours. These are birds of the sombre pine-woods, inhabiting high latitudes; but in their various greens and reds and yellows they are like tanagers and other tropical families, and form an exception to the rule that birds of brilliant plumage are restricted to regions of brilliant sunlight. No fewer than four species of this genus (Loxia) figure in the list of British birds; three of these may be dismissed in a few words:--