374 THE BIRDS OF SHERWOOD FOREST. 



of the American species, and the whole of the Australian 

 genus Eurostopodus, have the rictus without bristles, 

 and yet have the claw strongly pectinated. 



All these theories are plausible, and I believe all may 

 be occasionally exemplified. The feathers of the head 

 may be infested with vermin, and the bird then natu- 

 rally uses its foot as the only instrument whereby it can 

 free itself from its tormentors, and so brings its toothed 

 claw into use. Again, chafers and other large insects 

 may be at times caught with the foot, in the manner of 

 the kestrel ; the long bristles of the rictus may become 

 clogged or displaced in use ; the foot again is the only 

 means at the bird's disposal for straightening them, and 

 in this the toothed claw may assist. I cannot think, 

 however, that any of these uses is the one for which 

 most of the species of this family are furnished by their 

 Creator's wisdom with an instrument so peculiar. 



My own observations have long led me to suspect 

 another use. I am not sure whether the same idea has 

 not been mentioned by some naturalist, though I know 

 not by whom ; but, apart from this, I am more and 

 more convinced of its probability, and it has been still 

 further confirmed by a minute examination of the foot 

 of our European species, as well as some exotic ones. 



The larger number of species composing the family 

 of the Caprimulgidse do not perch across a bough, as 

 all other perching birds do, but lengthwise ; and it is 

 for this peculiar use that I believe the foot to be spe- 

 cially formed. 



In the ordinary position of perching birds, the twig 

 or bough is grasped by the foot, and thus a firm hold 

 is obtained, the weight of the body, by tightening the 

 tendons, increasing the stability ; but it is evident the 



