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CHESTNUT-SIDED WARBLER  Setophaga

pennsylvanica

11.5–12.5cm.

Common winter migrant to humid forest and edge, shade coffee plantations,

second growth. Mainly at mid–upper levels in canopy; joins mixed flocks.

Distinctive, with cocked tail and white eyering often recalling a gnatcatcher;

note lime-green upperparts and yellow wingbars; nonbr. ad. male has some

chestnut on flanks. Breeding female averages duller than male. SOUNDS: High

sharp (descending) chik, similar to Yellow Warbler. STATUS: Common Oct–Apr

on both slopes, mainly below 2100m, least numerous in drier nw. lowlands;

more widespread in migration, mainly Sep–Oct, Apr to mid-May. (Breeds e. N

America, winters Mexico to nw. S America.)

BAY-BREASTED WARBLER  Setophaga castanea 12–13cm. Transient migrant

in forest and woodland, second growth. Mainly at mid–upper levels in forest

canopy; joins mixed flocks. Rather large and stocky warbler, distinctive in

breeding plumage. Fall plumages can resemble Blackpoll Warbler, but Bay-

breasted has more spectacled expression (vs. pale eyebrow and dark eyestripe of

Blackpoll); plainer underparts with little or no dusky streaking and often tinged

buff on flanks; brighter greenish upperparts with thicker white wingbars; and

dark feet (yellowish on Blackpoll). SOUNDS: High sharp chik, slightly lower and

sweeter than Blackpoll. STATUS: Fairly common to common late Sep–Nov on

Caribbean slope, to 1800m, and scarce locally through winter on both slopes; uncommon Apr–early May,

mainly on Caribbean slope. (Breeds n. N America, winters Panama to nw. S America.)

BLACKPOLL WARBLER  Setophaga striata 12–13cm. Rare transient migrant in forest and woodland,

second growth. Mainly at mid–upper levels in canopy; joins mixed flocks. Rather large, thickset warbler

with long wings. Spring male distinctive; on spring female note narrow dark streaking above and below,

yellowish feet. Fall plumages all similar: olive above, tinged yellow below with diffuse dusky breast

streaking; note yellowish feet; cf. fall Bay-breasted Warbler. SOUNDS: High, sharp chik, slightly higher

than Yellow Warbler. STATUS: Rare to very rare mid-Oct to Nov, exceptional through winter and in spring;

most records from Caribbean slope and Central Valley, but possible anywhere. (Breeds n. N America,

winters S America.)

CERULEAN WARBLER  Setophaga cerulea 11–12cm. Transient migrant in forest

and woodland, second growth. Mainly at mid–upper levels in canopy; joins

mixed flocks. Distinctive, rather compact warbler with short tail mostly white

below, often held slightly cocked. On imm. and female note bold pale eyebrow,

unstreaked blue-green upperparts with bold white wingbars. SOUNDS:  High

sharp tsik, slightly higher than American Redstart. STATUS: Uncommon to rare

late Aug–Oct, mid-Mar to early May on Caribbean slope, rare on Pacific slope,

to 1500m. (Breeds e. N America, winters S America.)

BLACK-THROATED BLUE WARBLER  Setophaga caerulescens 11.5–12.5cm. Rare winter migrant to

forest and woodland, second growth, gardens. Mainly at low to mid-levels, often sallying and fluttering in

shady lower growth; usually independent of mixed flocks. Male stunning and unmistakable; female rather

drab but distinctive, with narrow whitish eyebrow and lower eye-arc set off by dark cheeks, olive upperparts

with small white check at base of primaries (all but absent on some imms.); note call. SOUNDS: Rather low

smacking tchk, suggests muted Lincoln’s Sparrow. STATUS: Very rare Oct–Apr; scattered records mainly

from Caribbean lowlands, also foothills on both slopes. (Breeds e. N America, winters Caribbean region.)