432 Birds of Colorado 



C. Tenth primary longer, from i to i of the ninth. 



a. Larger — wing over 2-5 ; upper-parts grey, no olive. 



V. vicinior, p. 438. 



b. Smaller — wing tmder 2-5 ; upper-parts oHve-green. 



V. belli, p. 437. 



Genus VIREOSYLVA. 



Medium-sized or small Vireos, with a bill somewhat variable in 

 length, but generally rather slender, narrow and compressed ; its 

 depth at the base not more than half the distance from the nostril 

 to the tip ; culmen straight with abruptly down-curved tip ; wing 

 long and pointed, the tenth (outer) primary either rudimentary and 

 wholly concealed, or if present, narrow and pointed and less than i^ 

 the length of the ninth ; ninth primary longer than the fourth ; tail 

 shorter than the wing, nearly even ; wings without bars. 



This genus containing a coixsiderable number of species, ranges over 

 the whole of temperate and tropical America. (For key, see p. 431). 



Red-eyed Vireo. Vireosylva olivacea. 



A.O.U. Checklist no 624 — Colorado Records — ? Allen 72, p. 176 ; 

 Thome 87, p. 264; Cooke 97, pp. 19, 112, 168, 218; Henderson 05, 

 p. 421 ; 07, p. 239 ; H. G. Smith 08, p. 189. 



Description. — Male — Crown slaty-grey, faintly margined with a 

 narrow line of dusky ; rest of upper-parts dull olive-green ; wings and 

 tail dusky, edged with olive-green ; a white superciliary line extending 

 over the ear-coverts, and a dusky loral stripe in front of the eye ; below 

 white tinged on the flanks and under tail-coverts with yellowish-oUve ; 

 imder wing-coverts pale yellow ; tenth (outer) primary obsolete ; iris 

 brownish-red, bill dusky grey, lower mandible rather paler, legs diisky. 

 Length 5-5 ; wing 3-10 ; tail 2-10 ; culmen -50 ; tarsus -63. 



The sexes are alike. A young bird is brown above and has the post- 

 ocular streak rather indistinct. 



Distribution. — Breeding throughout temperate North America, 

 except in arid districts, from British Columbia and Nova Scotia to 

 western Texa^s and Florida ; in winter south to the Bahamas and 

 through Mexico to Brazil and Bolivia. 



The Red-eyed Vireo is a somewhat rare svunmer bird in the plains 

 country of eastern Colorado and does not extend into the foothills or 

 moimtains. It arrives late in May and departs again in September. The 

 following are the recorded occurrences : Fort Lyon May 29th, three 

 times (Thome) ; Loveland, once seen May 12th by Prof. W. Osbiurn, 

 and Denver, one seen May 22nd, 1892, by H. G. Smith (Cooke) ; Limon, 



