CHEN ALBATUS. 95 



Brisson says, in his ' Ornithologia sive Synopsis Methodica ' (vol. vi. 

 p. 288, Anser niveus) : — " Estate nunquam in conspectum veniunt hujus 

 speciei Anseres ; hyeme autem gregatim volant." 



In addition to the above v^e must remember that all adult birds do not 

 breed every year, for various causes. Barren birds, as every keeper knov^s, 

 are very common in Ferdix cinerea. In Wood-Pigeons (^Columba palumbus) 

 it is an ordinary thing to find flocks of non-breeding individuals. Disease 

 also may have more efi'ect than we have discovered ; for the particular female 

 affected by it looks well, and when both sexes have the same dress no 

 diflPerence of plumage may be noticed. Non-breeding birds, according to my 

 belief, flock together and migrate together. 



Moulting governs the period of migration in some degree, as it is plain 

 that a migrating bird wants all his feathers. One that has to breed and 

 moult before migrating has enough to do to get through its work; in fact. 

 Swifts have not time always to finish the first before starting, to say nothing 

 of the latter. 



Edwards ('List of Birds,' pi. 252) figures the Blue- winged Goose. 

 Gray (in his ' Genera,' vol. iii.) makes Anas ccjerulescens^ Linn., the same as 

 A. hyperhoreus, Pallas ; I suppose "Anas'' should be "Anser.'' Baird does the 

 same. Mr. Dresser makes Chen ccerulescens, Gmel., of Audubon, a distinct 

 species from Chen hyperboreus, concerning which I have nothing to say at 

 present. Audubon (in my 8vo edition, 1840, 7 vols. — a much better one 

 than the later of 8 vols.) figures two Snow-Geese, adult and young female 

 (vol. vi. pi. 381). 



Edwards (vol. i. p. 152) remarks upon the Blue-winged Goose : — '' My 

 friend Mr. Light has told me there is a Goose which comes in summer to 

 Hudson's Bay, having its forehead, as it were, scorched with heat, and that 

 the natives firmly believe that these Geese, to avoid the winter's cold, fly 



o 2 



