1902.] F. Finn — General Notes on Variation in Birds. 177 



The Mallard {Anas boschas) of the Northern Hemisphere has been 

 domesticated since the beginning of the Christian era, and has given 

 rise to several distinct breeds. It varies to some extent when wild, and 

 a great deal in an unselected condition, as when kept in India ; the 

 varieties are best considered separately as to sex. 



The leading variations in drakes are as follows : — 



(rt) As in wild type ; rare ; correct for Rouen breed. 



(6) As above, but no bay breast or white collar, the pencilled-grey 

 of the under-surface running up to the green neck ; common ; said to 

 supervene with old age in domesticated birds of recent wild stock. 



(c) As in wild type, but bay of breast running cloudily along 

 flanks ; common. 



(d) Black with a white patch on breast. 



(e) Blue grey but with the usual markings ; bi-east warm brown. 

 (/) Pure white; correct for Aylesbury, White Call, and Pokin 



breeds, the last-named being tinged w^ith yellow. 



Intermediate types are very common, generally irregularly mark- 

 ed ; the breast is the first part to show abnormal white feathering, then 

 the wings. I have never seen a pure black duck among mongrel Indian 

 birds. 



One pied type recurs so frequently, in various colours, that it 

 deserves special mention. In this the head, breast and shoulders, and 

 hinder part of body are coloured, the rest white. This is the correct 

 maiking for the new Indian Runner breed, in which the coloured part 

 of the plumage must be fawn in tint. 



As in the fowl, the female varies more than the male : — 



(a) As in wild type ; rare. 



(b) As above, but light and dark head-markings obsolete, all head 

 being uniformly speckled ; speculum often whitish or brown .like rest 

 of wing. 



(c) As in wild type, but lighter; throat and eyebrows white, belly 

 shading into white ; speculum normal ; common. 



(d) As in wild type, but ground-colour much darker, rich warm 

 brown, correct for female of Rouen breed; common, 



(e) Black with white patch on breast ; speculum often whitish ; 

 common. 



(/) Blue-grey, often with dai^k edgings to the feather ; not 

 uncommon. 



{g) Pure white ; correct for Aylesbury and other white breeds. 



(/i) White, with coloured speculum and some dark colour on rest 

 of wings. Drakes are never marked like this. 



The intermediate types are very numerous ; the markings in pied 

 J. II. 23 



