306 



BRITISH BIRDS. 



tions. They closely resemble those of the Black-throated Chat, but are 

 not so brightly coloured, and the pale liver-coloured spots are larger. 

 They are light greenish blue in ground-colour, spotted with liver-brown 

 of varying degrees of intensity, usually in a zone round the larger end. 

 They measure -^l inch in length and -49 inch in breadth. 



The general colour of the upper plumage of a male in breeding-dress is 

 buff, richest on the lower back and dullest on the head, and shading into 

 pure white on the rump and upper tail-coverts. The cheeks, throat, and 

 sides of the neck are black ; the eye- stripes, which meet over the bill and 

 extend to the nape, are dull white. Wing and wing-coverts nearly black, 

 with obscure pale tips ; tail black, white at the base. The uuderparts are 

 white, washed with pale buff on the breast and flanks ; the under wing- 

 coverts are white, and the axillaries are black, tipped with white. Bill, 

 legs, feet, and claws black ; irides dark brown. The female, in breeding- 

 plumage, has the upper parts duller and greyer than in the male ; the eye- 

 stripes are scarcely visible, and the rump and upper tail-coverts are washed 

 with rufous. On the underparts the black throat is absent, the whole 

 under surface is bufi:, and the wings are brown. After the autumn moult, 

 but little change is visible in either sex ; but males of the year have the 

 black feathers of the throat and wings margined with buff. Young, in 

 first plumage, are like the young of other Chats, and have pale centres to 

 the feathers of both upper and under parts, except on the rump and belly. 

 The females of the Desert-Chat very closely resemble an allied species, the 

 Isabelline Chat (<S. isabeUina) , but they are always distinguishable by their 

 small feet. 



It has frequently been observed by ornithologists that the proportion of 

 birds of this species obtained in the female plumage is very small compared 

 with those obtained in the male plumage. Mr. Gurney estimates the pro- 

 portion in Algeria to be about one of the former to eight of the latter. It 

 is therefore very possible that the female birds assume the plumage of the 

 male, but gain it later in life, as is the case with many other birds. 

 Careful sexing of specimens by collectors would, however, place the matter 

 beyond all doubt. 



