The black-cheeked warbler (''Basileuterus melanogenys'') is a

New World warbler The New World warblers or wood-warblers are a group of small, often colorful, passerine birds that make up the family Parulidae and are restricted to the New World. They are not closely related to Old World warblers or Australian warblers. Most ...

, resident breeding

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

endemic to the

Talamancan montane forests The Talamancan montane forests ecoregion, in the tropical moist broadleaf forest biome, are in montane Costa Rica and western Panama in Central America. Setting The Talamancan montane forests cover a discontinuous area of in Cordilleran mountain ...

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 Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...

. It is normally found in

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

forests with a dense

bamboo Bamboos are a diverse group of evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family. The origin of the word "bamboo" is uncertain, bu ...

understory from 2500 m altitude to the timberline, but occasionally occurs as low as 1600 m. The breeding pair builds a bulky domed nest with a side entrance on a sloping bank or in a gully, and the female lays two white eggs. The black-cheeked warbler is 13–13.5 cm long and weighs 13 g. It has a rufous crown, long white supercilia and black cheeks. The upperparts are dull olive, the breast is olive-grey, and the belly is yellow-white. The sexes are similar, but the young bird is browner on the upperparts, has a dull supercilium, a greyer breast, and shows two cinnamon wingbars. Despite this species’ restricted range, it has three

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

. * ''B. m. melanogenys'', the nominate race described above, breeds in central and southern Costa Rica. * ''B. m. eximius'' is highly localised in a small area of western Panama, and is slightly whiter on the belly than ''melanogenys''. * ''B. m. bensoni'' is highly localised in a small area of west-central Panama, and is whiter below than ''eximius'', and a purer grey above. The black-cheeked warbler primarily feeds on

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

s and other small

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s, taken low in the undergrowth. The call note of the black-cheeked warbler is a hard ''tsit'', and the male's song is a lisping spluttered ''tsi tsi wee tsi tsi wu tsi wee''.

References

* Curson, Quinn and Beadle,''New World Warblers'' * Stiles and Skutch, ''A guide to the birds of Costa Rica'' {{Taxonbar, from=Q791198 black-cheeked warbler Birds of the Talamancan montane forests black-cheeked warbler black-cheeked warbler