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GNATWRENS AND GNATCATCHERS (POLIOPTILIDAE; 4 SPECIES)

New World family of very small, fine-billed, thin-legged, and relatively long-tailed birds. Ages

differ slightly (weak juv. plumage soon replaced by adult-like plumage); gnatcatcher sexes differ

in head pattern.

*NORTHERN [LONG-BILLED] GNATWREN  Ramphocaenus [melanurus] rufi­

ventris 12–12.5cm. Active but easily overlooked inhabitant of humid forest

edge, overgrown plantations, taller second growth, especially with vine tangles.

Forages actively, low to high in tangles and leafy foliage, often in pairs; tail

typically cocked and swung loosely around; sometimes associates with mixed

flocks. Distinctive, but cf. Tawny-faced Gnatwren. Juv. duller overall than

adult. SOUNDS: Song a dry to vaguely musical ringing trill, often rising and

falling (quality can suggest Northern Tropical Pewee), at times preceded by a

quiet tik or chortle, 1.5–3 secs; lower and harsher trills and chatters when

agitated. Calls rather wren-like: short dry tcherr and nasal scolding cheut, both can be repeated steadily.

STATUS: Fairly common on both slopes, to 1200m; more local in drier nw. lowlands. (Mexico to nw. Peru.)

TAWNY-FACED GNATWREN  Microbates cinereiventris 9.5–10.5cm. Incon­

spicuous inhabitant of humid forest, typically in shady understory. Forages on

and near forest floor, where hops and clambers actively, probing into leaf litter

and foliage; joins mixed flocks of antwrens. Distinctive, with tawny face offset by

black whisker, shorter bill and tail than Long-billed Gnatwren. Juv. darker and

duller overall than adult. SOUNDS: Downslurred, burry nasal nyeeah and staccato,

short dry chatters, often alternated; slightly plaintive, downslurred whistled

peeee, about 0.5 sec, repeated every few secs. Song (?) a prolonged medley of

mews, chatters, and rasping notes, at times interspersed with plaintive whistles.

STATUS: Fairly common to uncommon on Caribbean slope, locally to 1200m.

(Nicaragua to S America.)

*CENTRAL AMERICAN [WHITE-LORED] GNATCATCHER  Polioptila albi­

loris 11–12cm. Forest edge, scrubby woodland, and second growth; not usually

inside taller and more-humid forest. Forages actively, low to high, often in

pairs; long tail often cocked and swung loosely. Confusion possible with White-

browed Gnatcatcher, which favors more-humid habitats, often in forest canopy.

White-browed has broad white eyebrow extending well behind eye and im­

parting distinctive ‘open-faced’ expression, never has solid black cap. Breeding

male Central American attains solid black cap; juv. resembles female but face

pattern softer, upperparts tinged brownish. SOUNDS: Relatively low, slightly

downslurred burry zhheh, and a more hissing zzzh, at times doubled; lower and rougher than mews of

White-browed Gnatcatcher. Song an unhurried medley of mews, chips, and buzzes. STATUS:  Fairly

common on n. Pacific slope, locally to 800m. (Guatemala to Costa Rica.)

WHITE-BROWED [TROPICAL] GNATCATCHER  Polioptila [plumbea] bi­

lin­eata 10–11cm. Humid forest and edge, gallery forest. Singly or in pairs,

mostly flitting actively in canopy; comes lower at edges. Joins mixed flocks of

warblers, greenlets, honeycreepers. Note open white face on both sexes; cf.

Central American Gnatcatcher (occurs side-by-side locally in Northwest); no

seasonal change in appearance. Juv. resembles female but face pattern softer,

upperparts tinged brownish. SOUNDS: Overslurred, nasal mewing meéah and

clipped nasal meeh; distinctly higher than rough rasping calls of Central Ameri­

can. Song a high, overall descending, silvery slow trill, 2–3 secs. STATUS: Fairly

common to common on both slopes, to 1500m; uncommon and more local in drier nw. lowlands

(Mexico to w. Peru.)