THE GOAT-SUCKER. 255 



and leaves, and sometimes the cambium and even the wood, it 

 must, on the whole, be classed among those birds which are 

 eminently useful to man ; and one which comes from a far 

 country to perform its yearly service, and which performs 

 that without doing anything in the least injurious for the 

 goat-sucker consumes nothing but insects. Indeed, the 

 whole of the Chelidonian birds do good only, without the 

 least admixture of evil.* 



* The goat-sucker constitutes the type of the family Caprimulgidce ; 

 and although our European species has little of the owl in its aspect, 

 there are other forms of this extensive family, as the genus Podargus, 

 which are very owl-like; having a large, powerful, hooked upper man- 

 dible, large nocturnal eyes, a voluminous head, with elongated tufts or 

 ear-plumes, and a deep, soft, marble plumage. 



In the genus Caprimulgus, the margin of the gape is furnished with 

 long and strong bristles, which evidently assist in the capture of food; 

 the claw of the middle toe is elongated, and has its inner margin deeply 

 pectinated or comblike; a structure, the object of which has not been 

 explicitly determined. Some have supposed it useful as enabling the 

 bird to seize its insect prey with the foot; others as adapted for clearing 

 the bristles of the beak, of the limbs and wing-cases of beetles, or the 

 wings of moths. For ourselves, we incline to the idea that it assists the 

 bird in its peculiar mode of perching on the bare branches of trees, its 

 head being lower than the tail. 



The voice of the goat- sucker is very remarkable. While perched on a 

 branch, on palings, or the ridge of any building, as the shadows of 

 evening increase, it depresses its head, and utters a sonorous, churring 

 sound, a continuous vibratory jar, its throat all the time swelling out and 

 quivering. This sound is seldom uttered on the wing, but the male 

 when playfully chasing his mate through the boughs of trees, frequently 

 utters a small squeak, repeated four or five times in succession. The 

 churring noise is no doubt a love-note of invitation to the female, and 

 not to the beetles, as the author seems to intimate. M. 



