Yellow Warbler 449 
Genus DENDROICA. 
Bill variable but generally rather conical, the basal width and depth 
about equal; culmen slightly decurved ; rictal bristles quite obvious ; 
wing with the four outer primaries about equal ; tail shorter than the 
wing, about even or slightly rounded ; plumage in most cases with 
white wing-bars and white patches on the tail. 
This is the largest genus of the family ; it contains about thirty-four 
species, twenty-three of which have been found in the United States, 
the others inhabiting Mexico, Central America and specially the West 
Indies. For key, see p. 439. 
Yellow Warbler. Dendroica estiva. 
A.O.U. Checklist no 652—Colorado Records—Allen 72, pp. 148, 
175 ; Trippe 74, p. 232 ; Henshaw 75, p. 192; Minot 80, p. 226; Allen 
& Brewster 83, p. 158; Drew 85, p. 15; Beckham 85, p. 141; Bren- 
ninger 88, p. 64; Lowe 92, p. 101; H. G. Smith 93, p. 244 ; Cooke 97, 
pp. 19, 114, 218; 04, p. 52; Dille 03, p. 74; Henderson 03, p. 237 ; 
09, p. 239 ; Warren 06, p. 23 ; 08, p. 24; 09, p. 17 ; Chapman 07, p. 113 ; 
Gilman 07, p. 194; Markman 07, p. 158 ; Rockwell 08, p. 176. 
Description.—Male—Above yellow with an olive wash on the back, 
clearer and richer on the head and rump ; wings and tail dusky, mostly 
edged and tipped with yellow ; below rich yellow with chestnut streaks 
on the chest and flanks ; iris brown, bill dusky horn, legs light horny. 
Length 4-50; wing 2-55; tail 2-0; culmen -42; tarsus -70. 
The female resembles the male, but is rather duller in colour through- 
out; the head is like the back and the chestnut streaks are usually 
absent, or if present quite indistinct. Size smaller—wing 2-30. Young 
birds are very similar to the females. 
Colorado birds are, some of them, intermediate between the typical 
eastern form and the more yellowish form, with narrower and less 
marked chestnut streaks below (D. «. sonorana), which occurs in New 
Mexico and Arizona, but on the whole it is perhaps safest to refer them 
to the typical race. The Yellow Warblers of the west have been also 
distinguished from those of the east under the name of D. w. morcomi 
or D. e. brewstert, but for this there hardly seems to be any justification. 
Distribution.—Breeding throughout the greater part of Canada and 
the United States, except Florida, Georgia and the south-western states 
from Texas to Arizona, south in winter across the Gulf of Mexico to 
south Mexico, central and South America as far as Peru and the Amazon 
Valley 
In Colorado the Yellow Warbler is perhaps the commonest of its 
family in summer. It arrives from the south the first week in May, 
Pueblo May 4th (Beckham), El Paso co. same date (Aiken), and leaves 
FF 
