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*ORANGE-BILLED SPARROW  Arremon aurantiirostris 14.5–16.5cm. Humid

forest, taller second growth, plantations. Pairs or singles hop on ground in shady

understory; rarely perches in low vegetation except when singing. Distinctive,

but mostly retiring: orange bill often gleams like a beacon in shadowed forest.

Mostly dark bill of imm. can be retained into mid-winter. Comprises 2 groups

in Costa Rica that may represent species: Northern Orange-billed Sparrow A.

[a.] rufidorsalis on Caribbean slope, averages broader and bolder white eyebrow,

plumage darker and richer overall; Western Orange-billed Sparrow A. [a.]

aurantiirostris on s. Pacific slope averages duller eyebrow, usually tinged grayish

at rear. SOUNDS: Northern call a slightly rough smacking tchik! Song a very high, squeaky, often slightly

jerky warble, 1–4 secs. Western call a high, thin, slightly tinny clipped tsit. Song higher, thinner, faster-

paced than Northern, with variably tinny, tinkling quality, 1.5–3.5 secs. STATUS: Fairly common on both

slopes, to 1200m on Pacific slope, to 800m on Caribbean slope. (Mexico to S America.)

SOOTY-FACED FINCH  Arremon crassirostris 15.5–17cm. Humid foothill

forest and edge, especially ravines and streamside thickets. Pairs or singles forage

on or near ground in shady understory, hopping over ground, at times ranging

into low fruiting shrubs; sings from low perches. Distinctive but mostly retiring:

note bushy whitish mustache, rusty crown; also bright yellow belly at some

angles. Juv. duller and browner overall, without rusty cap; note trace of paler

mustache, dark throat; cf. juv. Chestnut-capped Brushfinch, which has pale

throat. SOUNDS: High, piercing to slightly metallic sibilant tsii tsiíh, 2nd note

stronger; sometimes short series of high notes, 1st slightly lower but stronger.

Song a high, squeaky, slightly jerky chanting warble, can be prolonged to a min or longer; averages slower-

paced, more piercing than Costa Rican Brushfinch. STATUS: Fairly common to uncommon on Caribbean

slope, mainly 600–1800m; uncommon on cen. Pacific slope. (Costa Rica to w. Panama.)

CHESTNUT-CAPPED BRUSHFINCH  Arremon brunneinucha 17–19.5cm.

Humid highland forest and edge, adjacent second growth and brushy thickets.

Pairs or singles forage in shady understory, hopping over ground and tossing

leaves with bill; at times ranges into fruiting shrubs and low trees. Distinctive

but retiring: puffy white throat often gleams in shady understory, bordered by

black collar; also note bright rusty cap with variable buff margin (weak in

Northwest, distinct in Talamanca Mts.). Cf. Costa Rican Brushfinch of s. Pacific

slope (mainly lower elevations). SOUNDS: High thin ssi and sii. Song a short

medley of thin, slurred, sibilant whistles, 1–2 secs; also longer series up to 30 secs

or more, including thin wiry trills; overall slower-paced, less varied, and more sibilant than Costa Rican

Brushfinch. STATUS: Fairly common on both slopes, mainly 1200–2500m on Pacific slope, 900–2500m on

Caribbean slope. (Mexico to S America.)

COSTA RICAN [STRIPE-HEADED] BRUSHFINCH  Arremon costaricensis 18–​

19.5cm. Humid foothill forest edge, second growth thickets, plantations. Pairs

or singles forage in shady understory, hopping over ground and tossing leaves

with bill; at times ranges into fruiting shrubs and low trees. Distinctive but

retiring: puffy white throat often gleams in shady understory; also note broad

gray eyebrow on black head, lack of black collar. Cf. Chestnut-capped Brush­

finch, mainly of higher elevations. Juv. duller overall with olive head, trace of

adult head pattern. SOUNDS: High, thin, slightly piercing tsit ot tsiit, may run

into short twitters. Song a high, thin, jerky, slightly tinny twitter in bursts of

1–2 secs every few secs; also faster-paced prolonged twittering to 30 secs or more; overall faster-paced,

more twittering and varied than thinner, sibilant songs of Chestnut-capped Brushfinch. STATUS: Fairly

common, mainly 300–1200m. (Costa Rica to w. Panama.)