774 
U. S. P. H. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 
ANAS BOSCHAS, L. 
Mallard ; Green Head. 
Anas boschas, Linn. Syst. Nat. I, 1766, 205.— Forster, Phil. Trans. LXII, 1772, 383.— Gmelin, I, 538.— Wilson, 
Am. Orn. VIII, 1814, 112 ; pi. l.xx.— Bon. Obs. 1825, No. 256.— Ib. List, 1838.— Aud. Orn. Biog. 
Ill, 1835, 164 ; pi. 221.— Ib. Syn. 276.— Ib. Birds Amer. VI, 1843, 236 ; pi. 385.— Eyton, Mon. 
Anat. 1838, 140. 
Jlnas (Boschas) boschas, Jenyns, Man. 233. 
Anas adunca, L. Syst. Nat. I, 1766, 206.— Gm. I, 538 ; monstrous variety. 
Jlnas domeslica, Gmelin, I, 1788, 538. 
Anas (Boschas) domestica, Sw. F. Bor. Am. II, 1831, 442.— Nuttall, Man. II, 1634, 378. 
" Anas bicolor, Donovan, Br. Birds, IX; pi. 212." (Supposed hybrid with Cairina moschata, or mu^pvy duck. 
Jenyns.) 
" Anas puiyureo-viridis, Schinz." (Supposed hybrid with Cairina moschata. Bonap.) 
Anas maxima, Goese, Birds Jam. 1847, 399. (Suppo. c ed hybrid with Cairina moschata ) 
Fuligula viola, Bell, Annals N. Y. Lyceum, V, 1852, 219. New York. (Supposed hybrid witli Cairina moschata.) 
Anas glocitans, Aud ; pi. 338. 
Anas brcweri, Aud. Orn. Biog. IV, 1838, 302 ; pi. 338.— Ib. Syn. 277.— Ib. Bird's Amer. VI, 1843, 252 ; pi. 387. 
Anas audubonii, Bon. Geog. Li>t, 1838. The three last names are based on the same specimen, supposed to be a 
hybrid between Anas boschas and Chaulelasmus ttreperus, possibly with Aythya vallisneria. 
Mallard, Pennant, Arctic Zool. II, 563.— Lath. Syn. Ill, n, 489. 
Sp. Ch. — Male. Head and neck bright grass green, with violet gloss, the top of the head duller ; a white ring round the 
middle of the neck, below which and on the fore part and sides of the breast the color is dark brownish chestnut. Under parts 
and sides, with the scapulars, pale gray, very finely undulated with dusky ; the outer scapulars with a brownish tinge. Fore 
part of back reddish brown ; posterior more olivaceous. Crissum and upper tail coverts black, the latter with a blue gloss. 
Tail externally white ; wing coverts brownish gray, the grrater coverts tipped first with white, and then more narrowly with 
black. Speculum purplish violet, terminated with black ; a recurved tuft of feathers on the rump. 
Female with the wing exactly as on the male. The under parts plain whitish ochrey, each feather obscurely blotched with 
dusky. Head and neck similar, spotted and streaked with dusky ; the chin and throat above unspotted. Upper parts dark 
brown, the feathers broadly edged and banded with reddish brown parallel with the circumference. 
Length of male, 23 ; wing, 11 ; tarsus, 1.70 ; commissure of bill, 2.50. 
Hah. — Entire continent of North America and greater part of Old World. 
A large duck, much exceeding the mallard in size, but quite similar in general appearance, 
is occasionally shot in the United States and in Europe, and described by the various names 
given in the synonomy. It is generally supposed to be a hybrid with the muscovy, Cairina 
7noschata, although, from the constancy of its markings and the absence on the face of the 
peculiarities of the muscovy, it may be questioned whether, after all, it be not entitled to 
specific rank. The Anas breweri of Audubon is different from this form, and may, possibly, be 
a hybrid with the gad wall, as suggested by its describer. 
This species is generally considered as identical with the barn-yard duck, and presents one of 
the few cases where the original is well known of a domesticated animal. A difference 
between the wild and tame mallard, according to Giraud, is to be found in the much broader, 
harder, and more horny feet of the latter. 
