The ruddy treerunner (''Margarornis rubiginosus''), is a passerine bird which is endemic to the highlands of

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

and western Panama. This treerunner is found in hills and mountains from 1200 m up to the timberline, in forests and adjacent edges and clearings. It builds a large enclosed oval nest 25 m high in the crown of a tree on the underside of a thick branch. The nest is camouflaged with mosses and

epiphyte An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

s and has a downward pointing entrance tunnel at its base. The eggs are undescribed, but members of this family typically lay two white eggs. The adult ruddy treerunner is 16 cm long, weighs 18 g and looks like a small, short-billed woodcreeper, but has soft, rather than rigid, tail spines. It has bright rufous upperparts and a white

supercilium The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head.Dunn and Alderfer (2006), p. 10 Also ...

. It has a white throat and otherwise tawny underparts. Young birds are almost identical to the adults. The call is a sharp ''tsit'', and the song is a twittering trill. The ruddy treerunner forages for large insects, spiders and their eggs and larvae in mosses, plant debris,

bromeliad The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...

s and other epiphytes. It creeps along branches and up stems - but uses its tail for support less than a woodcreeper does. It is seen alone, in pairs, or as part of a mixed-species feeding flock.

References

* Daniel J. Mennill and Stéphanie M. Doucet, ''First description of the nest and eggs of the ruddy treerunner (Margarornis rubiginosus))'' Cotinga 24 (2005): 109—110 * Stiles and Skutch, ''A guide to the birds of Costa Rica'' {{Taxonbar, from=Q864282 ruddy treerunner Birds of Costa Rica Birds of Panama ruddy treerunner ruddy treerunner