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BLACKBURNIAN WARBLER  Setophaga fusca 11.5–12.5cm. Winter migrant

to varied forest and woodland habitats, second growth. Mainly at mid–upper

levels, often with mixed flocks. Male stunning and unmistakable, female/imm.

have same pattern, with pale back stripes, triangular dark cheek patch; yellow

throat and breast usually have warm orangey tone, unlike lemon-yellow of

superficially similar Townsend’s Warbler. SOUNDS: High sharp tsik, at times

with vaguely tinny quality. STATUS: Fairly common to common Sep–Apr on

both slopes, mainly 500–1600m, in smaller numbers to lowlands, rarely to

2500m; more widespread in migration, mid-Aug to Oct, Apr to mid-May.

(Breeds e. N America, winters Costa Rica to S America.)

TOWNSEND’S WARBLER  Setophaga townsendi 11.5–12.5cm. Winter migrant

to highland oak and cloud forest, shade coffee plantations, adjacent second

growth. Mainly at mid–upper levels; often with mixed flocks. Distinctive, with

dark cheek mask, yellow breast, streaked flanks; cf. imm. Hermit Warbler.

Hybrid Townsend’s × Hermit show variable mixed features, often with Hermit-

like face but streaked flanks. SOUNDS: High, sharp, rather abrupt tik, much like

Black-throated Green Warbler. STATUS: Uncommon to rare Oct–Mar on both

slopes, 1200–3000m, with a few from late Sep and into early Apr. Hybrids with

Hermit Warbler not reported from Costa Rica but likely occur. (Breeds w. N

America, winters w. US to w. Panama.)

BLACK-THROATED GREEN WARBLER  Setophaga virens 11.5–12.5cm.

Winter migrant to varied woodland and forest habitats, shade coffee plantations,

adjacent thickets and second growth. Mainly at mid–upper levels; often with

mixed flocks. Note yellow face with weak olive frame to cheeks, greenish back;

cf. Townsend’s Warbler. SOUNDS:  High, sharp tik like Townsend’s Warbler.

STATUS: Fairly common to common Oct–Apr on both slopes, mainly 1000–

3000m; more widespread in migration, Sep–early Nov, Apr to mid-May, when

uncommon in Caribbean lowlands, scarce in Pacific lowlands. (Breeds N

America, winters Mexico to nw. S America.)

HERMIT WARBLER  Setophaga occidentalis 12–13cm. Rare winter migrant to highland forest, adjacent

second growth and semi-open areas with non-native cypress and pine trees. Mainly at mid–upper levels,

sometimes with mixed flocks. Distinctive, with yellow face, whitish breast, unstreaked flanks; imm.

female has dusky cheek patch suggesting Townsend’s Warbler, and beware Hermit × Townsend’s hybrids,

which overall resemble Hermit but have dark streaks on sides and flanks. SOUNDS: High sharp tik like

Townsend’s Warbler. STATUS: Rare mid-Sep to Mar on both slopes, mainly 800–2200m s. to n. Talamanca

Mts. Hybrids with Townsend’s Warbler not reported from Costa Rica but likely occur. (Breeds w. N

America, winters Mexico to Costa Rica.)