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RUDDY TREERUNNER  Margarornis rubiginosus 15–16cm. Small, bright

rusty ovenbird of humid highland forest, adjacent second growth and clearings

with trees and shrubs. Forages low to high, as singles or small groups, climbing

along trunks and mossy branches, clambering among twigs, bamboo stalks,

dead-leaf clusters; often with mixed flocks including bush tanagers. Could

suggest a small woodcreeper but has short pinkish bill, brighter plumage, pale

eyebrow (weaker on juv.). SOUNDS: High thin sip and varied high thin twitters,

at times in prolonged rising and falling series. Song a high, thin, descending or

slightly overslurred, rapid sibilant trill, about 1 sec. STATUS: Fairly common to

common, from timberline down to 1400m in Northern Mts., down to 1800m in Central and Talamanca

Mts. (Costa Rica to w. Panama.)

*NORTHERN SPOTTED BARBTAIL  Premnoplex [brunnescens] brunneicauda

13.5–14.5cm. Small dark ovenbird of humid mossy forest, adjacent second

growth. Forages mainly at low to mid-levels, as singles or pairs, clambering in

tangles and bromeliads, hitching along branches and trunks, cf. woodcreepers;

often with mixed flocks of antwrens, Basileuterus warblers. Note dark brown

plumage, bold buff spotting on underparts, pale eyebrow. SOUNDS: High,

thin, overslurred ssip, at times doubled or in short series. Song a rapid-paced,

rather insect-like, dry ticking trill, tirrrrrrrrrr, 0.7–1.5 secs; could suggest a

wren. STATUS: Fairly common on both slopes, mainly 600–2500m. (Costa

Rica to w. Panama.)

STREAKED XENOPS  Xenops rutilans 12–13cm. Small arboreal ovenbird of

humid foothill and highland forest, adjacent taller second growth, plantations.

Forages mainly at mid–upper levels on twigs and smaller branches, among vine

tangles; rather agile, climbing and often hanging upside-down like a chickadee,

hammering at twigs; does not use its tail for support. Ones and twos often with

mixed flocks, which at lower elevations can also include Plain Xenops. Note

distinct pale streaking on crown, back, and underparts, wedge-shaped bill,

habits; white whisker often less striking than on Plain. SOUNDS: Poorly known

in Costa Rica. Song a slightly descending, unhurried series of (6–8) high,

slightly sibilant chips, tsip tsip..., 2–3 secs, 1st 1–2 notes often hesitant. STATUS: Uncommon to scarce on

both slopes, 800–2500m. (Costa Rica to S America.)

*PLAIN XENOPS  Xenops [minutus] genibarbis 11–12.5cm. Small arboreal

ovenbird of humid forest, adjacent taller second growth, gallery forest. Mainly

at mid-levels in fairly open subcanopy on twigs and smaller branches, among

vine tangles; habits much like Streaked Xenops, and often with mixed flocks.

Note contrasting white whisker, lack of pale streaking on crown, back, and

underparts, wedge-shaped bill, habits. SOUNDS:  Song a high, fast-paced,

rippling trill, overslurred and slowing at the end, 1–2 secs; typically starts with

1 or more high tsip or pip notes; suggests Grayish Woodcreeper but higher,

thinner, more rippling. Calls a high thin tseep and hissing psssi. STATUS: Fairly

common on both slopes, locally to 1500m; scarce and local in drier nw.

lowlands. (Mexico to S America.)