VIREO. 



473 



olive-green and yellow; length 5.00-6.00, wing 

 2.90-3.00 (2.94), tail 2.10-2.20 (2.19), bill from 

 nostril .28-.30 (.29), tarsus .70-.73 (.71). Nest in 

 woods, in undergrowth or lower branches of small 

 trees. Eggs .79 X -57. Sab. Eastern North 

 America, north to Fort Simpson and Hudson's 

 Bay, breeding chiefly north of United States; 

 south, in winter, through eastern Mexico to 

 Guatemala. 

 629. V. solitarius (Wils.). Blue-headed Vireo. 

 g*. Back, etc., more grayish olive-green, less abruptly 

 (if at all) contrasted with the duller ash-gray 

 of head and neck ; gray of cheeks less abruptly 

 contrasted with white of throat ; sides and flanks 

 less strongly tinged with olive-green and yellow. 

 (Young in first winter much browner than cor- 

 responding stage of V. solitarius.') Length 5.00- 

 5.60, wing 2.85-3.00 (2.90), tail 2.10-2.30 (2.16), 

 bill from nostril .28-.31 (.30), tarsus .70-78 (.74). 

 Eggs .79 X -55. Sab. Western United States, 

 east to Eocky Mountains, but chiefly (if not ex- 

 clusively) Pacific coast in summer; in winter, 

 south through western Mexico 629a. V. soli- 

 tarius cassinii (Xantus). Cassin's Vireo. 

 f 1 . Larger (wing decidedly more than 3.00, tail not less than 

 2.20). 



Similar in plumage to V. solitarius, but upper parts 

 much darker (" nearly uniform blackish plum- 

 beous, with only a faint tinge of greenish on the 

 back, which is essentially concolor with the 

 crown") ; wing 3.03-3.30, tail 2.21-2.31, bill from 

 nostril .30-.36, tarsus .72-.75. Sab. Higher 

 southern Alleghanies (western North Carolina, 



etc.) — . V. solitarius alticola Brewst. 



Mountain Solitary Vireo. 1 



e 2 . Sides and flanks tinged with plumbeous-gray, but with little 



if any olivaceous or yellowish tinge; back, rump, and 



upper tail-coverts plumbeous-gray, very slightly, if at all, 



tinged with olive-green. 



Above plumbeous, or plumbeous-gray, with the usual 

 white markings on wings and sides of head ; lower 

 parts white, the sides and flanks strongly tinged with 

 plumbeous-gray; length 5.75-6.15, wing 3.05-3.30 



1 Vireo solitarius alticola Brewst., Auk, iii. Jan. 1866, 111. 

 60 



