LESSER SCAUP DUCK 277 



As with some other diving ducks many persons have noticed a disproportionate number of male 

 birds, in some places as great a discrepancy as 95% to 5%, but I do not know whether the sex dis- 

 tribution could be worked out for latitudes. We need a lot more detailed observation on the propor- 

 tions of the sexes at different stations in winter. 



Banded Specimens 



Of 32 Lesser Scaup banded at Avery Isle, Louisiana, on February 4, 1916, only two have been re- 

 covered: one in autumn, 1918, at Bee Creek, Illinois River, Illinois, the other on May 26, 1919, at 

 Fort Smith, Northwest Territory, Canada (U.S. Biological Survey). 



GENERAL HABITS 



A clear picture of the status, movements and range of this duck is more difficult 

 than one would suppose in a species so common. Of course this is due to constant 

 confusion with the Greater Scaup, and a partial confusion with the Ring-necked 

 Duck. The older writers, Audubon and Wilson, failed to recognize this as a true 

 species, although they both noticed a great range of variation in the weights and 

 sizes of Scaups. Wilson hit rather near the mark when he noticed that those which 

 frequented the seashore were "much the fattest," for these no doubt were mostly 

 of the larger species. 



The Lesser Scaup was differentiated by Eyton in 1838 and Giraud (1844) was the 

 first popular American writer who noticed it. As far back as his time it was already 

 recognized by the gunners of Long Island and went by the name of Creek Broad- 

 bill to distinguish it from the Greater Scaup, or Bay Broad-bill. There is little doubt 

 that most of Audubon's account of the Scaup refers to the present species, as his 

 plate certainly does. 



It is difficult and often impossible to discriminate between this and the Greater 

 Scaup in the field. Adult males may be recognized comparatively easily, but with 

 females and young the case is very different. With such individuals the observer 

 must have the bird in his hand and must carefully measure the wing and bill. Even 

 if this precaution is taken there will be an occasional specimen which will give some 

 trouble for the extreme measurements do actually overlap; that is, a very small 

 immature Greater Scaup may be about the same size as a very large female or im- 

 mature Lesser Scaup. Thus specimens with poorly developed plumage and with a 

 wing measurement of around 200 mm. give the impression of real intergrades. In fact 

 several writers have thought that hybrids between the two Scaups were of common 

 occurrence. But it seems to me we have little evidence that such crossings are any- 

 thing but very rare. If we knew in detail the physiology and anatomy of these two 

 species of ducks it seems quite likely that some fundamental differences could be 

 demonstrated. Until that time we must be content to describe the ranges and the 

 life-histories. Certainly the general habits are similar, but the distribution, both 

 summer and winter, the direction and time of migration, and the winter dispersal 



