Beautiful Treerunner
Margarornis bellulus
Rare but unique within a tiny range near the border of Panama and Colombia. Small brown bird that hitches along mossy limbs in humid cloud forest. Look for a buffy eyebrow, a white throat, and pale spotting on the underparts. Sexes alike. Similar to Pearled Treerunner but no range overlap; also note duller brown (not rufous) upperparts. Typically seen singly or in pairs, often following a mixed-species flock.
Identification
The beautiful treerunner is 14 to 15 cm (5.5 to 5.9 in) long and weighs 18 to 19 g (0.63 to 0.67 oz). The sexes have the same plumage. Adults have a buffish-white supercilium that extends to the nape, a dull reddish brown line behind the eye, dark brown ear coverts with whitish streaks, and a dark brown "moustache" with white spots that become stripes toward the neck. Their crown is olive brown and their upperparts and wing coverts warm olive-brown. Their flight feathers are dark fuscous with tawny-ochraceous edges. Their tail is dull reddish brown; the ends of the tail feathers lack barbs, giving a spiny appearance. Their throat is whitish and the rest of their underparts rufescent brown. Their upper breast has whitish oval spots with dark brown rims that become narrow stripes on the belly. Their iris is brown, their maxilla brownish, their mandible pinkish, and their legs and feet gray.
Taxonomy
Some authors have proposed that the beautiful treerunner and the pearled treerunner (M. squamiger) are conspecific or sister species, but these treatments were disproven in a 2011 publication.<p>The beautiful treerunner is monotypic.
- Scientific name
- Margarornis bellulus
- Authority
- Nelson, 1912
- Order
- Passeriformes
- Family
- Furnariidae
- Genus
- Margarornis
Range and habitat
The beautiful treerunner has a disjunct distribution within Panama. It is found in the Serranía de Majé of Panamá Province and in several ranges in the extreme east of Darién Province. It inhabits montane evergreen forest, mostly at elevations between 1,350 and 1,600 m (4,400 and 5,200 ft) but in a few places as low as 900 m (3,000 ft).
- Migration
- Resident species
Behavior
The beautiful treerunner is a year-round resident throughout its range.<p>The beautiful treerunner feeds on arthropods. It usually forages as part of a mixed-species feeding flock. It acrobatically moves through the forest's subcanopy, gleaning prey from branches and epiphytes, sometimes while hanging upside down.<p>Nothing is known about the beautiful treerunner's breeding biology.<p>As of September 2023, xeno-canto and the Cornell Lab of Ornithology's Macaulay Library each had a single recording of a beautiful treerunner call and none of its song.
Conservation
- Population trend
- stable
Photos
Distribution
Bird Calls
Other Birds
Lemon-rumped Warbler
Phylloscopus chloronotus
Small leaf warbler with many extremely similar relatives. Like other “Pallas’s-type” leaf warblers, has olive-yellow upperparts, pale underparts, prominent brow and crown stripes, double wingbars, and a pale rump. Unlike Ashy-throated and Buff-barred Warblers, lacks any white on outer tail edges. Pallas’s averages yellower-headed and brighter overall. Gansu and Chinese Leaf Warblers can be incredibly similar, but Lemon-rumped averages whiter-browed and yellower-bellied than the former, more contrastingly-marked on the head than the latter, and darker-billed than both. As with many other physically similar leaf warblers, best distinguished by voice and habitat. Breeds in coniferous and mixed forests at mid- to high-elevation forests, though may descend into foothills in the winter. Two song types are both highly distinctive; one is a buzzy, descending rattling trill and the other is a series of high-pitched clicking twitters. Call is a loud, strident pair of notes: “pse-tew!”
Buff-bellied Monarch
Neolalage banksiana
A strikingly beautiful flycatcher with a bright golden belly, a pure white face, and a black back, cap, and chest band. Tail black with white tip, rump white. Wings black with large white panels. Found in most wooded habitats up to 1200 meters of elevation, including gardens. Usually forages low down, frequently fanning its tail and always moving. Behavior separates it from the superficially similar Vanuatu Whistler. Common calls include a scolding “tze” and a long, quavering thin whistle.
Ethiopian Thrush
Turdus simensis
A long-legged short-tailed thrush with brown upperparts, heavily spotted buff underparts, and a strongly marked face. In flight, shows distinctive large buff patches in the broad wings. Pairs and small groups occupy open montane habitats, including moorland, grassland, and woodland, often in heavily grazed and burned areas. Runs long distances on the ground hunting invertebrates, stopping bolt upright and flicking its wings. The song is a series of rough, spitted whistles. Calls include an upslurred “wheet” given singly or in series, and a dry rattle.
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