48 



IDENTIFICATION. 



species, and for ready reference arrange them in the alphabetical 

 order of their genera. 



Is our bird black with a red breast ? No. He is not migratorius, 

 and it would have been a wonder if he were. Has he a black throat 

 and breast? No. He would have been the third of his kind to be 

 caught in this country if he had. He is not atrigularis. Turn him 

 over and look at his axillaries. Are they red ? No. He is not a 

 Redwing. Are they white ? No. He is not a Fieldfare nor a Missel 

 Thrush ; and if he were a Fieldfare he would have a blue rump. 

 What colour are his axillaries ? Pale yellow. That alone will 

 distinguish him. He is olive brown above and whitish below, 

 with a number of triangular brown spots and streaks about him. In 

 fact, he is T. musicus, otherwise the common Song Thrush, whom 

 recent classifiers have promoted to the second place on the British 

 list. 



And now, with a view to advancing beyond the mere knowledge 

 of the bird's name, let us take the feathers off our Thrush. 



These chiefly consist of 

 the penna, or contour 



• feathers, which are so- 

 called from their giving 

 the outline of the body. 

 They are exposed to the 

 light. The other feathers, 



• the down feathers, are 

 hidden from the light. In 

 the contour feathers we 

 have a main stem or axis, 

 the •vexillum, or vane, 

 divided into the solid four- 

 sided shaft or rachis, and 

 the hollow, somewhat 

 rounded hollow end, we 

 know as the quill, or cala- 

 mus, which ends in a small 

 aperture through which it 

 receives the vascular pulp. 

 With the sac in which this 



is embedded are connected the muscles which give the feathers motion. 

 The vane bears the plates, or barbs, which are linked together at their 

 free ends by the barbules, which are again generally interlinked by 

 hooklets. In the Ostrich we have free barbs, and, consequently, 

 loose plumes, but the case is exceptional. In a good many birds 

 each quill has two vanes, one being the shaft, the other the aftershaft, 

 which always springs from the underside ; and, occasionally, shaft 

 and undershaft are almost equal, and a "double feather" is the 

 result. 



The down feathers, hidden from the light in adults, are the first 

 feathers of the young bird which are generally replaced by \}cie. penna, 

 and their barbs invariably remain soft and free. In some birds we 

 have a third kind of feather, one with a long shaft and a sort of brush 

 of barbs ; this is a "filoplume." In the Ardeid^e, and in some of the 

 FalconidcC, there is a fourth kind of feather, the summit of which 



