( 130 ) 



A SHORT DESCRIPTION OF THE SEQUENCE OF 

 PLUMAGES IN SOME PAL.E ARCTIC SURFACE- 

 FEEDING DUCKS. 



BY 



E. LEHN SCHIOLER, Copenhagen, Denmark. 



The following remarks apply to the Teal {Anas c. crccca), 

 Pintail {A. acuta), Garganey {A. querquedula) , Gadwall 

 {A. strepera), Shoveler {Spatula clypeata), Mallard (.4. p. 

 platyrhyncha) and Wigeon {A. penelope), the number of 

 specimens of the remaining palsearctic species seen being so 

 small that nothing definite can be said about their moults. 



The total number of specimens amounts to about 2,500, of 

 which about 2,300 are in my own collection, the rest in the 

 University Zoological Museum of Copenhagen. This series 

 of ducks has been collected in the course of twenty years, 

 about 1,700 have been sexed by myself and their skeletons 

 preserved. 



The study of the moults of the surface-feeding ducks is 

 not an easy one, examination of dry skins alone very soon 

 proving insufficient. It is true that the juvenile tail-feathers 

 may be taken as a safe guide to distinguish young from so- 

 called old birds, but as these feathers are often changed quite 

 early in the young bird's first year, their evidence only goes a 

 certain way. The oviduct and to some extent the ovary are 

 in autumn and winter specimens more certain evidence, the 

 narrow undeveloped oviduct of a young bird being easily 

 distinguishable from the thickened prolapsed oviduct of an 

 old or older bird that has laid eggs the preceding summer or 

 before. In surface-feeding ducks the skeleton, i.e., sternum 

 and pelvis, may also be of some service in estimating age, as 

 it is possible to follow the progress towards pneumaticity in 

 these bones. This progress, however, does not take place 

 according to the same rules in every species, and the time 

 taken in attaining the maximum degree of pneumaticity for 

 each species apparently differs to some extent, but this subject 

 is too large to enter into more fully here. Used together these 

 characters make it possible to trace the sequence of plumages 

 in these interesting birds, and in doing away with guesswork 

 they give the following results a tolerable degree of certainty. 



The Teal {Anas c.crecca). 

 Female. — The downy duckling gets its first feathers on 

 the shoulders and flanks ; when about five or six weeks old 

 it wears the first juvenile plumage, recognizable b}^ the juvenile 



