223 JOTTINGS ABOUT BIRDS. 



tions at all, and of course come very naturally 

 under my division : " Birds in which both sexes are 

 . brightly coloured, and which rear their young in 

 holes or in covered nests." Of Mr. Allen's third 

 exception, the Sheldrakes, or what British ornithol- 

 ogists call Mergansers (Mergus), the down of these 

 birds is pale in tint, and would be most conspicuous 

 in an open site, and therefore the same remarks 

 apply as to the birds in Clangula. With regard to 

 the Grosbeaks, a group in which the brilliantly 

 coloured male is said not only to sit upon the open 

 nest but even to sing whilst doing so, I must retort 

 by pointing out the fact, that these birds generally 

 nest in dense cover, where the sitting bird is admir- 

 ably shielded from view by the surrounding foliage. 

 This latter exception, however, comes more naturally 

 into that group which I designated as " Birds in 

 which the plumage of both sexes is showy or brilliant 

 in colour, and which nidificate in open nests," if both 

 sexes are known to incubate. The male Blackcap 

 performs his share of the duty of incubation, and 

 he also repeatedly sings while sitting on the nest, 

 but he is so well shaded by surrounding vegetation 

 that he is hidden from enemies, and may do so with 

 impunity. The male Blackbird will also occasionally 

 sit on the nest in the female's absence, but he is so 



