OWLS. 337 



the posterior edge of this bare space, and also behind 

 the aperture of the ear, is a kind of ruff, composed of 

 several series of short, recurved, compact feathers. 

 The transition from this kind of ear to that of the owls 

 is direct. In fact, we have in the hen-harrier a decided 

 conch, which is always described as peculiar to the owls. 

 This conch, it may here be explained, is just a large 

 am'icular aperture, with elevated membranous margins, 

 which are beset with feathers. When its anterior mar- 

 gin is much elevated and stiffened by the tubes of the 

 feathers, that part is named the operculum or lid. 



The largest auricular aperture of any British fal- 

 conine bird, excepting the genus Circus, examined by 

 me, that of the golden eagle, is five-twelfths of an inch 

 in length ; the smallest of any strigine bird, that of the 

 passerine owl, is also five-twelfths ; but of course, in the 

 latter, the ear is, in proportion to its size, very much 

 larger than in the eagle. 



It is a curious fact, however, which may startle the 

 ornithologists, who generally seem to attend very lit- 

 tle to these things, that many birds have ears as large 

 as those of some of the owls. Thus, the Creeper, Cer- 

 thia familiaris, has the head five-twelfths and a half in 

 height (without the plumage), while the external aper- 

 ture of the ear is two-twelfths, and the conch, includ- 

 ing its margins, two-twelfths and a half. The Wren, 

 Troglodytes europseus, presents exactly the same pro- 

 portions. The Greenfinch, which has the head seven- 

 twelfths deep, has the external aperture of the ear two- 

 twelfths and three-quarters in diameter, the commence- 

 ment of the slit-like meatus two-twelfths and a half. 

 The Thrush, Turdus musicus, has the head eleven 



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