312 BRITISH BIRDS. 



The presence of the Nightjar in a district is generally made known by its 

 singular notes. These have been likened by numerous writers to the 

 noise made by some kind of machinery. They remind one of the note of 

 the Grasshopper Warbler, but are much louder and deeper. If tigers 

 purr like cats, I should imagine they would make a noise something like 

 the Goatsucker. Its ordinary note may be very closely imitated by 

 sounding the letter r sufficiently rapidly to make the tongue vibrate, and 

 then, endeavouring to give it a slightly guttural sound, making it occa- 

 sionally swell and sink in loudness, and slightly alter in tone, as it is 

 produced by inhaling or exhaling the breath. The note is very powerful, 

 and on a still evening may be heard at a long distance. This churring 

 note is uttered at irregular intervals, and usually lasts a minute or so, 

 sometimes as much as four or five minutes, and is said to be confined to 

 the male bird, and only uttered when it is perched. It is generally heard 

 in the dusk and at night ; but in the height of summer, especially in the 

 pairing-season, it is occasionally heard during the day. In addition to 

 the notes already described, the male bird occasionally makes a whoop- 

 like sound ; but how this is performed, whether by the throat or the wings, 

 is at present unknown. It is often heard when the birds are chasing each 

 other in early summer. 



The food of the Nightjar is supposed to consist exclusively of insects of 

 various kinds. It is very fond of catching cockchafers, and eats many of 

 the large moths and night-flying beetles ; and Macgillivray discovered 

 that it feeds on caterpillers. It is said to snatch the Ghost-Swift Moth 

 from the grass-stems ', but more often takes this species as it flutters above 

 them. The Nightjar is a voracious bird, and captures a great many insects 

 in a single night. It is also said to eat slugs. The refuse of its food is 

 cast up in the form of pellets. The bird has been said to hunt for its food 

 with its large mouth wide open; but this is certainly an error. It can 

 open and close its bill in a moment, and does so as occasion requires, 

 resembling in this respect Swallows and Swifts. There has been much 

 controversy as to the use of the large bristles at the gape of the Nightjar, 

 and more as to the uses of the serrated claw. The bristles may aid it 

 considerably in capturing its prey, and are usually found on the gapes of 

 most insect-feeding birds; but there are many Nightjars in different parts 

 of the world that have no such appendages. The use of the serrated or 

 combed claw remains still unknown, though many ingenious theories have 

 been invented to explain it. Some writers have thought that it was used 

 to aid the bird in capturing its prey ; others have said that it was employed 

 to comb out its long rictal bristles, or to rid its plumage of parasites ; 

 whilst Naumann was of opinion that it was of service to the bird when 

 perched lengthwise on the branches. 



The Nightjar may possibly pair for life; and each successive season 



