INTRODUCTION. xi 



in colour, and that of the female dull and sombre, and which nidifi- 

 cate in open sites. — The merest tyro in ornithology is aware that the 

 plumage of the female bird is in a great many cases far more sombre than 

 that of the male. Until comparatively recently the cause of this pheno- 

 menon was never dreamed of. It is an ascertained fact that the colour of 

 many female birds is connected in no small degree with their mode of 

 nidification, and that the sitting bird is protected by the harmony which 

 exists between its own sober plumage and the colour of the surroundings 

 of its nesting-site. Let us glance over the nesting-habits of some of our 

 best-known birds, and learn the working of this law. The males of many 

 of our common birds possess extreme brilliancy of plumage, whilst their 

 females are of such dull and inconspicuous colours that an inexperienced 

 person would suppose them to belong to different species. The gorgeous 

 Pheasant {Phasianus colchicus) , for instance, has a mate whose garb is dingy 

 and subdued in the extreme. Her sober plumage, however, is of the greatest 

 importance ; for on this circumstance in part depends the very existence of 

 her species. She builds her slight nest on the ground, and her plumage 

 harmonizes with the dead bracken and dry herbage around, and most 

 effectually conceals her from her enemies. A still more striking instance 

 is to be found in the Black Grouse (Tetrao tetrix). The male bird is 

 dressed in a rich garb of purplish black, but his mate does not resemble 

 him in the least degree ; indeed, so widely does she differ in the colour of 

 her plumage as to defy even the most expert ornithologist unacquainted 

 with the matter, so far as outward appearances go, to class her as the same 

 species as her mate, her plumage being mottled brown of various shades. 

 But this diversity of plumage between the sexes serves the great purpose 

 of shielding the female during the season of nidification on the brown 

 heathery wastes where she rears her young. Take another instance. The 

 Mallard, or Wild Duck {Anas boschas), exhibits such brilliant tints as to 

 render him one of the showiest of our native birds; but his mate is of dull 

 and inconspicuous colours, which harmonize closely with the tints of her 

 nesting-site, which is an open and exposed one. Again, the male Teal 

 (Anas crecca) is richly adorned, but his mate is so dull in plumage as to 

 suggest the idea of their being distinct species. By this great differ- 

 ence in the sexes the same end is served ; for the female Teal builds 

 an open nest, and the safety of that nest and its eggs depends on her dull 

 and sober plumage. Amongst our smaller birds we have many instances : 

 the Blackbird {Merula merula) mated to a dull brown spouse, who sits in 

 an open nest, and the Ring-Ouzel (M. torquata) may be cited. The male of 

 the latter species is showy, rich black and grey, with a snow-white baud 

 across the breast j the female is brown, and the band across the breast is 

 ^ull_a plumage in harmony with the brown tints of the moorland, where 

 she sits upon her open nest comparatively safe. The male Chaffinch 



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