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YELLOW-BELLIED TYRANNULET  Ornithion semiflavum 8–9cm. Tiny,

short-tailed flycatcher of humid lowland forest, taller second growth. Mainly in

canopy and subcanopy, where overlooked easily. Gleans in foliage, dead-leaf

clusters; does not usually sally or hover. Told from Brown-capped Tyrannulet by

slaty gray vs. brown cap, voice. SOUNDS: Strident, overslurred or rising sweéh, at

times doubled or in short series; nasal chips and clucks when agitated. Song

repeated steadily, a slightly descending series of (usually 3–5) plaintive whistles,

deee-dee-dee-di, last note sometimes upslurred. STATUS: Uncommon to fairly

common on both slopes, to 600m. (Mexico to w. Panama.)

BROWN-CAPPED TYRANNULET  Ornithion brunneicapillus 8–9cm. Tiny,

short-tailed flycatcher of humid lowland forest, taller second growth. Habits

like Yellow-bellied Tyrannulet; best told by voice in small area of overlap; also

note brown crown. SOUNDS: High, upslurred plaintive sweeih; nasal chips and

clucks when agitated. Song repeated steadily, a slightly descending series of

(usually 3–5) plaintive whistles, last 1–2 notes sometimes upslurred; unlike

Yellow-bellied Tyrannulet, typically preceded by, or interspersed with, rising

call: sweeeh, deee-dee-dee-di.…STATUS: Uncommon to fairly common on Carib­

bean slope, to 900m. (Nicaragua to nw. S America.)

NORTHERN BEARDLESS TYRANNULET Camptostoma imberbe 9.5–10.5cm.

Open woodland, second growth, semi-open areas with trees, especially in drier

areas. Low to high, mainly at mid–upper levels; hops and flutters, plucking

food from foliage. Posture often fairly upright, tail held below body plane and

loosely wagged. Note bushy crest (rarely held flat), small bill with bright orange

base, habitual tail pumping; fresh plumage has broad cinnamon wingbars,

fading to whitish. Central American Beardless Tyrannulet tends to perch more

horizontally, with tail cocked, plumage more contrasting, with yellowish belly,

whitish wingbars; note voice. SOUNDS: Slightly overslurred peért and softer,

drawn-out peeeeu; slightly descending, measured series of (usually 3–8) downsluured notes, dee dee dee...;

short bubbling deedl-idl-it. Song a varied short series of piping reedy whistles, typically including 1–2

louder notes, at times repeated over and over, such as pi pii pii pee PEE pii-pi. STATUS: Fairly common in

nw. lowlands, locally to 1600m around Central Valley. (Mexico to Costa Rica.)

*CENTRAL AMERICAN [SOUTHERN] BEARDLESS TYRANNULET  Camp­

tostoma [obsoletum] flaviventre 9.5–10.5cm. Open woodland, second growth,

semi-open areas and scrub with taller trees, plantations. Habits much like

Northern Beardless Tyrannulet but often holds tail cocked, posture less vertical.

Note bushy crest (rarely held flat), yellowish belly, whitish wingbars, voice; cf.

Northern Beardless Tyrannulet. Juv. duller and browner above, with buffy

wing­bars. SOUNDS: Calls average stronger, less plaintive than Northern Beard­

less. Downslurred, slightly emphatic peéur and overslurred peeéu, sometimes

followed by short rolled squeak; slightly descending series of (usually 3–7)

plaintive whistles, pwee pwee.…Song a varied, often prolonged repetition of piercing, slightly overslurred

to descending whistles, singly or in series of 2–3 notes every 1–2 secs: peeéu, peeéu, peeh-peeh, peeéu, peeéu-

peeh-peeh, peeéu, peeéu.…STATUS: Fairly common to uncommon on s. Pacific slope, locally to 1000m.

(Costa Rica to Panama.)

*MOUSE-COLORED TYRANNULET  Phaeomyias murina 11–12cm. Distinc­

tively drab small flycatcher of lowland second growth, scrubby thickets, forest

edge, plantations. Typically inconspicuous at low to mid-levels in shrubs and

smaller trees, where gleans for insects. Note dull buffy wingbars, broad pale eye­

brow; cf. appreciably smaller beardless tyrannulets. SOUNDS: Overslurred, nasal to

slightly squeaky chatter, chi-chi-chi-chi-chi-chi, about 0.5 sec, sometimes repeated

steadily. Song a slightly rising, nasal to burry chattering crescendo, ch-ch-ch-ch-

chichichichir, about 1 sec, repeated steadily. STATUS: Scarce and local in interior

valleys of s. Pacific slope; scattered reports elsewhere; first recorded Costa Rica in

1996; likely spreading with deforestation. (Costa Rica to S America.)