_Turdus swainsoni_, CAB. Tschudi, Fauna Peruana, 1844-46, 188.—? SCLATER & SALVIN, Ibis, 1859, 6 (Guatemala).—SCLATER, P. Z. S. 1858, 451 (Ecuador); 1859, 326.—IB. Catal. 1861, 2, no. 11.—BAIRD, Birds N. Am. 1858, 216; Rev. Am. B., 1864, 19.—GUNDLACH, Cab. Jour. 1861, 324 (Cuba).—IB. Repert. 1865, 229.—PELZELN, Orn. Brazil. II. 1868, 92 (Marambitanas, Feb. and March).—LAWR. N. Y. Lyc. IX, 91 (Costa Rica).—RIDGWAY.— MAYNARD.—SAMUELS, 152.—COOPER, Birds Cal. 6.—DALL & BANNISTER. _Turdus minor_, GMELIN, Syst. Nat. I, 1788, 809 (in part). _Turdus olivaceus_, GIRAUD, Birds L. Island, 1843-44, 92 (not of LINN.). _(?) Turdus minimus_, LAFRESNAYE, Rev. Zoöl. 1848, 5.—SCLATER, P. Z. S. 1854, 111.—BRYANT, Pr. Bost. Soc. VII, 1860, 226 (Bogota).—LAWRENCE, Ann. N. Y. Lyc. 1863. (Birds Panama, IV, no. 384.) SP. CHAR. Upper parts uniform olivaceous, with a decided shade of green. The fore part of breast, the throat and chin, pale brownish-yellow; rest of lower parts white; the sides washed with brownish-olive. Sides of the throat and fore part of the breast with sub-rounded spots of well-defined brown, darker than the back; the rest of the breast (except medially) with rather less distinct spots that are more olivaceous. Tibiæ yellowish-brown. Broad ring round the eye, loral region, and a general tinge on the side of the head, clear reddish buff. Length, 7.00; wing, 4.15; tail, 3.10; tarsus, 1.10. HAB. Eastern North America; westward to Humboldt Mountain and Upper Columbia; perhaps occasionally straggling as far as California; north to Slave Lake and Fort Yukon; south to Ecuador and Brazil. Cuba, GUNDLACH; Costa Rica, LAWR. Specimens examined from the northern regions (Great Slave Lake, Mackenzie River, and Yukon) to Guatemala; from Atlantic States to East Humboldt Mountains, Nevada, and from intervening localities. The extremes of variation are the _brownish_-olive of eastern and the clear _dark_ greenish-olive of remote western specimens. There is no observable difference between a Guatemalan skin and one from Fort Bridger, Utah. HABITS. The Olive-backed Thrush, or “Swamp Robin,” has very nearly the same habitat during the breeding season as that of the kindred species with which it was so long confounded. Although Wilson seems to have found the nest and eggs among the high lands of Northern Georgia, it is yet a somewhat more northern species. It does not breed so far south as Massachusetts, or if so, the cases must be exceptional and very rare, nor even in Western Maine, where the “Ground Swamp Robin” (_T. pallasi_) is quite abundant. It only becomes common in the neighborhood of Calais. It is, however, most widely distributed over nearly the entire continent, breeding from latitude 44° to high Arctic regions. It winters in Guatemala and southward as far as Ecuador and Brazil.