774 U. S. p. R. E. EXP. AND SXTRVETS — ZOOLOGY — GENEKAL REPORT. 



ANAS BOSCHAS, L. 



Jllallard ; Green Head. 



^nas hosohas, Lmu. Syst. Nat. I, 1766, 905.— Forster, Phil. Trans. LXII, 1772, 383.— Gmelin, I, 538.— Wilson, 

 Am. Orn. VIII, 1814, 112 ; pi. Ixx.— Bon. Obs. 1825, No. 256.— Ib. List, 1838.— Acd. Cm. Biog. 

 Ill, 1835, 164 ; pl. 221.— Ib. Syn. 276.— Ib. Birds Amer. VI, 1843, 236; pi. 385.— Etton, Mon. 

 Anat. 1838, 140. 



•3nas (Boschas) boschas, Jentns, Man. 233. 



«9nas adunca, L. Syst. Nat. I, 1766, 906. — Gm. I, 538 ; monstrous variety. 



Jlnas domestica, Gmelin, I, 1788, 538. 



Jlnas {Boschas) domestica, Sw. F. Eor. Am. II, 1831, 442. — Nuttall, Man. 11, 1834, 378. 



" ^nas bicolor, Donovan, Br. Birds, IX; pl. 212."" (Supposed hybrid with Cairina rmschata; or muscovy duck. 

 Jenyns.) 



" ^nas purpureoviridis, ScHinz," (Supposed hybrid with Cairina moschata. Bonap.) 



Jnas maxima, GoeSE, Birds Jam. 1847, 399. (Supposed hybrid with Cairina moschata) 



Fuligula viola, Bell, Annals N. Y. Lyceum, V, 1852, 219. New York. (Supposed hybrid with Cairina moschata.) 



^nas glocitans, Aud ; pl. 338. 



Jnas breweH, Ann. Orn. Biog. IV, 1838, 302 ; pl. 338.— Ib. Syn. 277.— Ib. Bird's Amer. VI, 1843, 252 ; pl. 387. 



•dnas audubonii. Boh. Geog. List, 1838. The three last names are based on the same specimen, supposed to be a 

 hybrid between jlnas boschas and Chaulelasmus streperus, possibly with ^ythya vallisneria. 



Mallard, Pennant, Arctic Zool. II, 563. — Lath. Syn. III,ii, 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 laiter with a bliie gloss. 

 Tail externally white ; wing coverts brownish gray, the grfater 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 bander! with reddish brown parallel with the circumference. 



Length of male, 23 ; wing, 11 ; tarsus, 1.70 ; commissure of bill, 2.50. 



Hab. — 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 

 moschata, 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 gadwall, 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 mucb broader 

 harder J and more horny feet of the latter. 



