382 CAPRIMULGIDJE. 



and the captured insect immediately finds itself overwhelmed 

 with the viscid saliva secreted by the faucial glands. 



That the bristles along each side of the upper mandible 

 assist this bird while feeding on the wing, by increasing the 

 means of capture by the mouth, there can be little doubt — 

 though it is to be remarked that one section of the Family, 

 containing among others the American Night-Hawks (Chorde- 

 diles), is not so provided ; but the use of the serrated claw 

 on each middle toe is not so obvious ; and zoologists have 

 delighted in exercising their ingenuity to explain the func- 

 tion of this organ, which, equally with the maxillary bristles, 

 is not possessed by all the Caprimulgidce, while it is found 

 also in several other groups of birds by no means related to 

 them. Gilbert White thought he had distinctly seen the 

 Goatsucker "put out its short leg whilst on the wing, and, 

 by a bend of the head, deliver somewhat into its mouth." 

 Hence he not unnaturally inferred that the use of the ser- 

 rated claw was to aid in the capture of prey. Atkinson also 

 quotes (Comp. Orn. p. 108) the opinion of a correspondent 

 to the same effect, but the very weak grasping-power of the 

 bird's foot forbids our accepting this explanation. Other 

 uses have been assigned to this organ, namely to comb out 

 the rictal bristles — which seems inadmissible, since many 

 genera of the Family want them though possessing the ser- 

 rated claw — or to clear the mouth from the sharp hooks on 

 the legs of insects — as suggested by Mr. Hay ward (Mag. 

 N. H. iii. p. 449) and others, while some have supposed it 

 is supplied as a means of getting rid of parasites — a process 

 which Wilson says he actually saw in the case of a captured 

 bird of an allied American species, Caprimulguscarolinensis*. 

 Mr. Sterland believes (B. Sherw. p. 174) that this feature 

 is correlated with the bird's practice of sitting, as before 

 stated, lengthways on a branch — the serrated edge of the 

 claws being " placed in exactly the best position for prevent- 

 ing the foot from slipping sideways " — an inconvenience 



* The observation is doubtless true so far as it goes, but too much importance 

 must not be attached thereto. Birds generally use their claws for this purpose, 

 and birds in captivity especially do so if denied the means of dusting themselves. 



