321 
Distinctions. Superficial attention to the above description might confuse this species 
with the Bay-breasted, but the white throat and cheeks are distinctive (Compare with 
Figure 291). Spring birds with their yellow cap, 
chestnut sides, and white underparts; and autumn 
ones white below, yellowish green above, and yellow- 
ish wing-bars are easily recognized. 
Field Marks. The white underparts and 
peculiar lemon-yellowness of the green above are good 
recognition marks even in plumages where the 
characteristic markings do not show. 
Nesting. In bushes some 3 feet from the ground 
in nest of strips of bark, leaf stems, etc., lined with 
tendrils and rootlets. 
Distribution. Eastern North America. In 
Canada, west to Manitoba and parts of northern 
Saskatchewan. 
Figure 290 
Chestnut-sided Warbler (male); 
natural size. 
660. Bay-breasted Warbler. Dendrotca castanea. L, 5*63. Male: finely striped 
with dull olive-ochre and black above; underparts white; top of head, throat, foreneck, 
and flanks bay colour (reddish chestnut); fore- 
head and cheeks black; a light ochre spot on 
side of neck (Figure 291). Female has all these 
characteristic marks, veiled and dimly indicated, 
but obvious enough for recognition. The 
autumn birds, however, are entirely different; 
above, yellowish green faintly striped with 
dark; below, white, more or less tinged with 
yellowish or buffy greenish; the bay of the sides 
is often indicated by a slight ruddy warmth or 
by individual, fully coloured feathers. 
Distinctions. Spring birds are distinctive 
enough. Autumn specimens resemble the juven- 
ile Black-poll so closely that often they can be 
separated only with difficulty even when in the 
hand. The Bay-breasted almost invariably has 
a certain amount of warm ochre on the flanks 
which is lacking in the Black-poll and the undertail-coverts are cream instead of pure 
white. The presence of wing-bars will distinguish these two species from other plain 
greenish Warblers. 
Field Marfa. The adult male is distinctive in colour. The spring female always 
shows enough of the bay breast for recognition. Adult autumn birds usually have a trace 
of the bay on the flanks and the warm ochreish of these parts can generally be seen in 
juveniles. When these characters fail to distinguish the species, however, close atten- 
tion will show that the breast colour is perfectly even and sharp eyes or good glasses will 
usually reveal very faint dark stripings showing on the sides of the breast of the Black- 
poll. None of these marks, however, can be seen except in the most favourable circum- 
stances, but in mixed flocks one can usually tell the proportion of each species with fair 
accuracy. 
Nesting. In coniferous trees, 5 to 20 feet above the ground, in nest of grasses and 
plant fibres lined with plant down and long hairs. 
Distribution. Eastern North America. In Canada, west commonly to Manitoba, 
less frequently to Saskatchewan and occasionally to southeastern Alberta, northwest to 
lake Athabaska. 
The Bay-breasted Warbler in spring migration prefers brushy growth 
in sandy wastes, roadsides, etc., but often comes close about the house 
plantation. The similarity of the autumn Bay-breasted and the autumn 
Black-poll, a bird in full plumage totally different, is one of the interesting 
phenomena of bird coloration. The autumn plumages of these two birds 
were at one time confused with each other under the name of Autumnal 
Warbler. 
01064—21 
Figure 291 
Bay-breasted Warbler (male); 
natural size. 
