356 
PASSERIFORMES 
Distinctions. Most specimens are unmistakable. Autumn females may be confused 
with autumn Black-polls and Bay-breasts, but the clearer yellow on throat, absence of 
greenish tinge below, and dark ear-coverts with conspicuous buff eyebrow-line are diagnostic. 
Field Marks. The bright orange or warm yellow confined to throat and breast and 
orange-yellow or buff eyebrow stripe in contrast with the dark cheeks and crown, make 
the best field marks. 
Nesting. In coniferous trees in nest of fine twigs and grasses, lined with grasses and 
tendrils. 
Distribution. Eastern North America. In Canada, west to Manitoba. Occasional 
in Saskatchewan. A single record for Alberta. 
659. Chestnut-sided Warbler, la fauvette a flancs marron. Dendroica pen- 
sylvanica. L, 5-14. Male: crown yellow (Figure 443); back black and grey in stripes, 
overwashed with yellowish green; below white with chestnut bands along flanks; two 
white or yellowish wing-bars. Female similar but duller. Juvenile an almost even yellow- 
ish green above, white below, cheeks grey; usually with suggestions of the chestnut sides 
of the adult. 
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 444). 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 443 
Chestnut-sided Warbler (male); 
natural size. 
660. Bay-breasted Warbler, la fauvette 1 poitrine baie. Dendroica castanea. 
L,J5*63. Male: finely striped with dull olive-ochre and black above; underparts white; 
top of head, throat, foreneck, and flanks bay 
colour (reddish chestnut); forehead and cheeks 
black; a light ochre spot on side of neck (Figure 
444). 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 dis- 
tinguish these two species from other plain greenish warblers. 
Field Marks. 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 circumstances, 
but in mixed flocks one can usually tell the proportion of each species with fair accuracy. 
Figure 444 
Bay-breasted Warbler (male); 
natural size. 
