The BIRCH-TREE SISKIN (_Linaria rubra_) is extremely common in Central Europe; by some authors it has been described as the Red Linnet, nevertheless it is so entirely unlike the Linnet, that only a novice in ornithology could mistake them, even at the first glance. The adult male of this species is a beautiful bird, as will be evident from the following description:--The front of the head is of a dark carmine-red, the rump pale red, and the feathers on the upper part of the body brown with light edges; the wing and tail feathers are black bordered with grey, and the wing exhibits two bands of a lighter shade than the remainder of its surface. The under part of the body is entirely white, the throat black, the fore part of the neck, upper breast, and sides, of a pale carmine-red, this last colour being entirely wanting, or very indistinct in the female. Shortly after moulting, the beauty of the plumage much deteriorates, as the feathers then become edged with grey. The young birds resemble the mother, and, when nestlings, are of a uniform brownish grey with brownish markings along the body; the head is blueish, the lower mandible yellow, the feet greyish brown, and the eye dark brown. The Birch Siskin is of nearly the same dimensions as the Linnet, being about five inches long and eight and a half inches across the wings; the female is in a very trifling degree smaller than her mate, and both birds differ from other Finches in the unusual elongation of the beak, which is somewhat conical and compressed at the sides, and by their comparatively strongly-developed wings. [Illustration: SISKIN, BULLFINCH, AND GOLDFINCH.]