ii8 Nightjar 



I do not think I need waste time witli any elaborate description 

 of the plumage. The bird is probably well-known to all. There 

 are, however, one or two points to which I should like to draw 

 attention. 



As regards the general colouration, the plumage is made up of 

 various shades of grey and brown, and the protective effect of this 

 combination of neutral tints is so remarkably perfect, that the bird 

 is invisible at the distance of a few feet, when sitting motionless on 

 the ground of its choice. It is, without any exception, the most 

 perfect example of protective colouration in an adult bird with which 

 I am familiar. 



The eyes are large, dark and rather prominent ; the feathers are 

 peculiarly soft and owl-like, ensiu-ing the necessary silence when 

 pursuing its prey ; both features being common to many nocturnal 

 birds. The mouth is split far back, and the gape very wide. The 

 upper mandible is beset on each side with a row of long, rather stiff, 

 movable bristles directed forwards and downwards. These bristles 

 are of service in directing the prey, which is always taken on the wing, 

 into the widely-opened mouth. 



The legs are short and weak ; three toes in front and one behind. 

 The claw of the middle toe is long and pectinated on the inner edge 

 only. The purpose of this serration has been much debated by 

 naturalists, but the solution is still to seek. 



Several theories have been put forward, but none of them appear 

 ver}' convincing : — 



1. It has been thought that the bird makes use of the 



pectination as a comb, to comb the scales of moths 

 and other insect remains off the rictal bristles. 



2. Others believe that it is used to disengage the clinging, 



hooked feet of beetles from the bill, so enabling the 

 prey to be swallowed. 



3. A third group suppose that it is of service as a prehensile 



organ, enabling the bird to seize and hold its prey 

 firmly with the foot. 



4. And lastly, the pectination is associated by some with 



the habit of perching lengthways on a bough, instead 

 of across it ; they suppose that it gives the bird a 

 more secure footmg, acting as a sort of patent non- 

 skidding toe. 



It is hardly worth while pointing out the objections to these 

 four theories ; they are varied and cogent. I believe that to arrive 

 at the real meaning of the serrated claw, we should have to go back 

 to the archaic stock from which the present Nightjars were evolved ; 

 to some primitive branch of the avian tree, lost in the countless 

 centuries which have elapsed since the differentiation of the modern 

 Caprimulgus. For it must be remembered that this genus contains 



