428 'PICARIAX' BIRDS 



\'er}- characteristic of a nightjar is its habit of crouching longitudi- 

 nally on a branch, instead of sitting transversely after the fashion of an 

 ordinary perching-bird ; and when on the ground these birds invariably 

 squat close down in the same manner as when on a branch. In fact 

 they neither perch nor stand. Although there are certain foreign 

 species without them, there can be little doubt that the bristles border- 

 ing the gape of the mouth serve to aid in capturing small insects ; but 

 whether the comb-like middle claw is for the purpose of cleansing 

 these bristles, as has been suggested, or has some other use, remains 

 at present uncertain. 



The two eggs, which are laid in a hollow on the bare ground or 

 the ledge of a cliff, are coloured for purposes of concealment just as 

 effectively as are the parent birds. Their ground-colour is white or 

 stone, upon which are one series of deep-seated lavender-grey markings, 

 and a more superficial set of light or dark brown ones, which may take 

 the form of either blotches, spots, or streaks. Another peculiarity of 

 the eggs, which average about i j- inches in length, is their regularly 

 oval form, so that they have neither a small nor a large end. In this 

 respect they resemble those of swifts — a circumstance which may 

 afford an additional argument for associating those birds with nightjars. 

 June and July form the la}'ing-season in England and Ireland, but in 

 the south of France the eggs are often deposited in May. As might 

 have been expected, young nightjars are clothed in down as soon as 

 they make their appearance in the world- — this down being grcj'ish, 

 darker above than below. 



Of the red-necked nightjar {Capriinnl^^us nificollis), whose proper 

 home is south-western Europe and the opposite coast of Africa, a single 

 example was taken near Newcastle in 1856. There is also a record 

 of a single British specimen, killed in Nottinghamshire in 1883, of the 

 Egyptian nightjar {C. (Tj^yptius), a species whose range extends from 

 Algeria to Baluchistan and Turkestan. 



Swift Swifts and swallows have such strong resemblance 



(Cvpselus anus) ^° "'^^ another in general appearance that the\' are 

 popularly supposed to be closely allied groups. 

 This, however, is not the opinion of the great majority of naturalists, 

 by whom swallows are regarded as a specially modified grouj) of 

 perching-birds, while swifts are believed to be " picarian " birds like- 

 wise specially adapted for a particular mode of life. On this view, 

 such resemblances as exist between the two groups are to be accounted 

 for by the similarity in the general mode of existence of their repre- 



