208 THE PILEOLATED WARBLER. 
No. 84. 
PILEOLATED WARBLER. 
A. O. U. No. 685 a. Wilsonia pusilla pileolata (Pallas). 
Description.—Adult male: Above bright olive green; forehead, sides of 
head, and underparts bright greenish yellow, tinged on sides with olive-green; 
crown, or “cap,” lustrous black; wings and tail fuscous and olive-edged without 
peculiar marks; bill dark above, light below; feet light brown. Adult female: 
Similar, but the black cap wanting, or, if present, less distinct. Jimmature; Like 
female without cap. Length about 4.75; wing 2.20 (56); tail 1.97 (50) ; bill .38 
(8.5); tarsus .75 (18.8). 
Recognition Marks.—Least,—pygmy size; black cap of male distinctive; 
recognizable in any plumage by small size and greenish yellow coloration. 
Brighter than V’. pusilla; not so bright as IV. p. chryseola. 
Nesting.—As next. 
General Range.—Western North America, breeding thruout the Rocky 
Mountain district, north to Alaska, west to Cascade Range in Oregon and Wash- 
ington and to Vancouver Island; during migrations over the entire western 
United States, and east irregularly to the Mississippi; south in winter over Mexico 
and Central America. 
Range in Washington.—Not common resident and abundant migrant on 
East-side; migrant only west of Cascades. 
Migrations.—Spring: May 1-15. 
Authorities.—Dawson, Auk XIV., 1897, 180. (T). (C&S). D'. Kb. D2. J. E. 
Specimens.—B. BN. E. P. 
THE pervading yellowness of this little bush-ranger will hardly serve to 
distinguish it from the equally common Lutescent Warbler, unless you are 
able to catch sight of its tiny silken crown-patch of black, the “little cap” 
which gives the bird its Latin-sounding name. With chryseola it is the smallest 
of our warblers, and it is one of the commonest, during migrations, on the 
Fast-side. The thickets have taken on full leaf before the bird arrives from 
the South, along about the roth of May, and the northward march is often 
prolonged till the first of June. So expert is the little Black-cap at threading 
briary tangles, that a meeting here depends upon the bird’s caprice rather than 
the astuteness of the observer. Willow trees are favorite stations during the 
spring movement, and these because of their scantier foliage afford the best 
opportunities for study. 
My impression is that the Pileolated Warbler must breed sparingly in 
eastern Washington. There is, however, only one summer record to substanti- 
ate this belief,—a bird seen in the valley of the Stehekin, June 22nd, 1906. 
The only song I have heard differed from the abruptly terminated crescendo 
of W. p. chryseola, being rather a well modulated swell, chip chip! chip!! 
chip!!! chip!!! chip!! chip! chip. 
