TURDIDyE — TIIK TUKUSHES. 



Caban., and alicicr, Baird. The first-named is totally unlike llie rest, 

 which are more closely related iu appearance. 



lu studying carefully a very large series of specimens of all the species, 

 the following facts become evident : — 



1. In autumn and winter the " olive " color of the plumage assumes a 

 browner cast than at other seasons ; this variation, however, is tlie same 

 in all the species (and varieties), so that in autunni and winter the several 

 species differ from each other as much as they do in spring and summer. 



Of these five species, two only (pallasi 

 and swainsoni) inhabit the whole breadth 

 of the continent; and they, in the three 

 Faunal Provinces over which they ex- 

 tend, are modified into " races " or " va- 

 rieties " characteristic of each region. 

 The first of these species, as the pullusi 

 var. pallasi, extends westward to the 

 Eocky Mountains, and migrates in winter 

 into the South ; specimens are very much 

 browner in the winter than in spring ; 

 but in the llocky Mountain region is a 

 larger, grayer race, the var. aiuhthoni. 

 This, in its migrations, extends along the 

 central mountain region through JNIexieo 

 to Guatemala; specimens from the northern and southern extremes of this 

 range are identical in all the specific characters ; but the southern specimens, 

 being in the fall and winter dress, are browner in color than northern ones 

 (spring birds) ; an autumnal example from Cantonment Burgwyn, N. M., is 

 as brown as any Central American specimen. Along the Pacific Province, 

 from Kodiak to Western Mexico, and occasionally straggling eastward toward 

 the Eocky Mountain system, there is the var. nanus, a race smaller than 

 the \'ar. pallasi, and -witli much the same colors as var. anduhoni, though the 

 rufous of tlie tail is deeper than in either of the other forms. In this race, 

 as in the others, there is no cUflerence in size between specimens from 

 north and south extremes of its distribution, because the breeding-] ilace 

 is in tlie Xorth, all Southern specimens being winter sojourners from their 

 Northern birthplace. 



The T. swainsoni is found in abundance westward to the western limit 

 of the Eocky Mountain system ; in the latter region specimens at all 

 seasons have the olive of a clearer, more greenish shade than in any Eastern 

 examples ; this clearer tint is analogous with that of the Eocky JNIountain 

 form of loallasi {anduhoni). In precisely the same region inhabiteil by the 

 pallasi var. nanus the swainsoni also has a representative form, — the var. 

 ustulatus. This resembles in pattern the var. swainsoni, but the olive above 

 is decidedly more rufescent, — much as in Eocky Mountain specimens of 



Tardus ustulatus. 



