TURDID.E — THE THRUSHES. 



Caban., and alicia', Baird. The first-named is totally mdike the rest, 

 which are more closely related in appearance. 



In studying carefully a \evy 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 the same 

 in all the species (and varieties), so that in autumn 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 svjai)t.mni) inhaf)it 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 paUasi 

 var. ^?f^//(?.si, extends westward to the 

 liocky Mountains, and migrates in winter 

 into the South ; specimens are very nuich 

 browner in the winter than in spring ; 

 but in the Kocky ^Mountain region is a 

 larger, grayer race, the var. audnhoni. 

 This, in its migrations, extends along the 

 central mountain region tln-ough Mexico 

 to (xuatemala ; 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 l)rowner 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 var. pallasi, and witli much the same colors as var. auduboni, though tlie 

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

 as in the others, there is wo difference in size between specimens from 

 north and south extremes of its distribution, l)ecause the breeding-jdace 

 is in the Nortli, all Southern specimens being winter sojourners from their 

 Northern birthplace. 



The T. sicainsuni is found in abundance westward to tlie western limit 

 of the Pocky jSTountain 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 2Jallasi {audnhoni). In precisely the same region inhabited by the 

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

 ustulatus. This resend)les in pattern the \ar. sioainsoni, but the olive above 

 is decidedly more rufescent, — miicli as in Pocky INFountaiu specimens of 



TiiTflua iistiilntiis 



