42 
ANAS BOSCHAS 
enumerated below; but this list is probably far from complete and is gleaned from 
Poll (1911), Leverkiihn (1890), Salvador! (1895) and Wormald (1914): Anas hoschas 
with Cairina moschata, Alopochen cegyptiacus, Casarca ferruginea. Anas undulata. 
Anas superciliosa, Anas melleri, Anas poecilorhyncha. Anas bahamensis. Anas 
sibilatrix. Anas flavirostris, Anas chlorotis, Anas querquedula, Lampronessa sponsa, 
Aex galericulata{?), Nyroca rufitia, Nyroca ferina, Nyroca collaris, Mergus mergan- 
ser, Metopiana peposaca. 
Still more remarkable was a cross with an Eider Duck described by W, Eagle 
Clarke (1912). This extraordinary bird was said not to dive, but to have the habits 
of a surface feeder. M. Jean Delacour of Cleres, France, has some curious hybrids 
between a male Asarcornis scutulata and a female Mallard. 
GEOGRAPHICAL RACES 
The question of possible races in this species is a diflBcult one because there is a rather wide range 
of variation in size. It is also more than likely that with such a common species, collectors wall 
pick out extra fine, or extra large specimens for preservation, particularly in the male sex. A 
very large series of Mallards from China, Palestine, and the United States in the collection of the 
Museum of Comparative Zoology shows no constant differences. The largest wing measurement 
is found in a specimen from the United States, of 296 mm., but Ilartert records one of 302 mm. The 
longest bill (a specimen from Palestine) measures 63 mm. Tarsal length is more constant, and ap- 
parently is always under 50 mm. Hartert (1920) finds that American Mallards are slightly larger 
than European ones. In the series before me, chiefly from eastern China, Palestine, and the United 
States, the following measurements were obtained, which exactly bear out Hartert ’s findings. 
Wings 
China 262-289 mm. Average 272 Males only 
Palestine 260-286 “ 273 
United States 260-296 “ 280 
It has often been remarked that Mallards from the Scandinavian peninsula are somewhat smaller, 
but this is not apparent. English and continental sportsmen have called attention many times to a 
supposedly smaller race of migrants coming from farther north in the winter. Hartert could not 
prove the existence of either a smaller northern form or a larger southern resident form, so that it is 
probable that no such races are distinguishable. F. W. Smalley (1919) assigns to these northern 
birds a weight of only two pounds and a wdng of 270-273 mm., while F. S. Beveridge (1919) claims 
that these “foreign” Mallards seldom weigh over one pound, fourteen ounces. The explanation is 
probably to be found, as Hartert suggests, in the arrival of northern-bred ducks, which are not so 
large or well nourished as the local ones. Perhaps also these migrants were hatched later, and are 
not so fully matured when they first reach England and France. 
In regard to the existence of a local form inhabiting Iceland, I must say that I am extremely 
skeptical. Iceland Mallards were given a name {Anas boschas subboschas) by Brehm (Oken’s Isis, 
1830, col. 997) but Hartert is doubtful about its validity, and from my own observations of three 
specimens I can see no reason w'hatever for recognizing such a form. 
The Greenland Mallard is in my opinion the only race that is worthy of recognition. 
