MERGANSER. 201 



bill is much as in the other, but duller iu colour ; nail at the tip 

 blackish ; the upper part of the head and neck ferruginous, paler 

 before; the feathers of the crown and nape much longer than in the 

 Goosander; chin and throat white; back, wing coverts, tail, and 

 sides of the body, ash-colour ; lower part of the neck before, breast, 

 and middle of the belly, white ; greater quills black ; scapulars 

 darker than the back; the ends of six of the second quills white for 

 two inches; but the last of these has the inner web, and remaining 

 parts of the others, pale ash-colour; the tail consists of twenty ash- 

 coloured feathers; legs orange, but paler than in the Goosander. 

 In this bird the trachea has no enlargement throughout its length. 

 This is mostly found at the same season, as the Goosander; but 

 appears to be far more common. In respect to the Mergus Castor, 

 supposed by Linnaeus and Brisson to be a distinct species, it seems 

 not to differ much from the Dun Diver ; it is less in size, the length 

 about twenty-two inches, breadth twenty-seven ; weight seventeen 

 ounces. The bill two inches and a quarter; in colour of plumage 

 much the same with that bird, but the neck has a greater mixture of 

 ash-colour, with a pale streak between the nostrils and eye ; the rest 

 as in the Dun Diver ; such an one was in my own collection, killed 

 on the Coast of Suffolk ; and was probably a bird of the first year; 

 and the Mergus rubricapillus a young male; but it appears that the 

 different varieties of plumage in this species may be accounted for, 

 as it requires three years before it arrives at complete feather : and 

 we learn, that the young of both sexes at first put on the appearance 

 of females. That the complete Dun Diver is the female of the 

 Goosander, will therefore be admitted ; but as both sexes have the 

 same plumage for at least two years, to identify the male, recourse 

 must be had to the anatomical structure of the windpipe; when, in 

 whatever state of plumage the subject may be, should there be found 

 two enlargements of that organ, there is no doubt of it proving a 

 male ; on the contrary, in the female there is no enlargement 

 throughout the whole of its length. As an additional proof of this, 



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