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GENUS BASILEUTERUS (4 species). Widespread neotropical warbler genus of forested and scrubby

habitats. Sexes similar, often paired year-round; juv. plumage held briefly, like adult within a week or two.

CHESTNUT-CAPPED [RUFOUS-CAPPED] WARBLER  Basileuterus delattrii

12–13cm. Woodland understory and edge, plantations, taller second growth,

brushy hedgerows. At low to mid-levels in fairly open understory, foraging in

foliage, often hopping with tail slightly cocked. Distinctive, with yellow under­

parts, rusty cap and cheeks, bold white eyebrow. No similar species in Costa Rica.

SOUNDS: High tinny chiin or chik, sometimes doubled or in short series. Song a

pleasant, fairly rapid chipping and jangling warble, 2–3 secs. STATUS:  Fairly

common on n. Pacific slope, locally to 2000m around Central Valley; mainly

600–1600m in interior valleys of s. Pacific slope. (Mexico to nw. S America.)

*STRIPE-CROWNED [GOLDEN-CROWNED] WARBLER  Basileuterus culi­

civorus 12–13cm. Humid foothill forest, adjacent taller second growth. In pairs

or small groups at low to mid-levels in shady understory, hopping actively and

often noisily, tail slightly cocked; joins mixed flocks. Distinctive, with yellow

underparts, striped crown (central crown stripe varies, yellow to orange); upper­

parts vary from grayish in Northern Mts. to olive on s. Pacific slope. SOUNDS: Song

a short, slurred sweet warble, 1–1.5 secs, ending with strongly upslurred note.

Call a dry chk or rattled trrk, at times run into chatters suggesting a wren.

STATUS: Fairly common on both slopes, mainly 900–2100m on Pacific slope,

300–1500m on Caribbean slope. (Mexico to Panama.)

BLACK-EARED (COSTA RICAN) WARBLER  Basileuterus [tristriatus] melan­

otis 12–13cm. Formerly known as Three-striped Warbler. Humid highland forest

and edge, adjacent taller second growth. Mainly at low to mid-levels in shady

understory; small groups forage actively in foliage, flipping and twitching tail;

often with mixed flocks. Strong head pattern distinctive—suggests Worm-eating

Warbler with a facial makeover. Juv. duller overall with diffuse head pattern, faint

paler wingbars. SOUNDS: High tik and rolled tsirr, often given when foraging.

Song a high, fairly fast-paced jangling twitter, at times prolonged to 15 secs or

more in duets, and short songs may run into each other. STATUS: Fairly common

on Caribbean slope, 1000–2200m; spills over locally to Pacific slope. (Costa Rica to w. Panama.)

BLACK-CHEEKED WARBLER  Basileuterus melanogenys 12.5–13.5cm. Humid

highland forest edge and understory, adjacent second growth and bamboo thickets.

Mainly at low to mid-levels, in pairs or small groups, foraging actively and

twitching tail; sometimes with mixed flocks. Distinctive, with contrasting white

eyebrow, rusty cap, blackish face. Juv. head sooty brown with weak pale eyebrow.

SOUNDS: Calls include high, lisping, downslurred tssi and short high twitters. Song

a high, thin, slightly tinny or squeaky jangling twitter, 1–2 secs, at times run into

longer duets; thinner and tinnier than Black-eared Warbler. STATUS:  Fairly

common from timberline down to 1600m. (Costa Rica to w. Panama.)

WRENTHRUSH (ZELEDONIIDAE; 1 SPECIES) Enigmatic single-species family

formerly merged into New World warblers. Sexes similar.

WRENTHRUSH  Zeledonia coronata 11–11.5cm. Distinctive but retiring, a

small plump bird of bamboo thickets and second growth at edges of humid

highland forest, damp ravines, adjacent páramo. Best detected by voice. Singles

hop, often rather quickly, on and near ground in dense tangles and bamboo; often

flicks wings. Habits, plus plump shape and dark plumage with bright orange

crown patch distinctive. Juv. plumage held briefly, duller overall than adult with

weak crown pattern. SOUNDS: Song a very high, thin, slightly piercing warbled

series of (usually 2–5) notes, 0.5–1 sec, such as tsi-si-síin, every 2–6 secs. Call

louder, a piercing, slightly ascending, very high thin siiii, about 0.5 sec, at times

given steadily in short series. STATUS: Fairly common from timberline down to 1500m in Northern Mts.,

down to 1800m in Central and Talamanca Mts. (Costa Rica to w. Panama.)