White-crested elaenia
The white-crested elaenia is a species of bird in subfamily Elaeniinae of family Tyrannidae, the tyrant flycatchers. It is found in Bolivia, Chile, Colombia, Ecuador, and Peru.
Taxonomy and systematics
The International Ornithological Committee recognizes these five subspecies of the white-crested elaenia:E. a. griseigularis Sclater, PL, 1859E. a. diversa Zimmer, JT, 1941E. a. urubambae Zimmer, JT, 1941E. a. albiceps E. a. modesta Tschudi, 1844The South American Classification Committee of the American Ornithological Society, the Clements taxonomy, and BirdLife International's Handbook of the Birds of the World recognize a sixth subspecies, E. a. chilensis, that the IOC treats as the Chilean elaenia. The SACC is seeking a proposal to recognize it as a species.
Subspecies E. a. modesta was originally described as a species and was later reclassified as a subspecies of the white-crested elaenia. Significant evidence now suggests that it should again be treated as a full species.
This article follows the five-subspecies model.
Description
The white-crested elaenia is long and weighs. It is a small to medium size elaenia with a small bushy crest. The sexes have the same plumage. Adults of the nominate subspecies E. a. albiceps have a mostly dull olive to olive-gray head with a partially hidden white or creamy white stripe in the middle of the crest. They have whitish lores and eyering. Their upperparts are dull olive to olive-gray. Their wings are dusky with white or whitish tips on the coverts that show as two wing bars. Their flight feathers have narrow whitish or yellowish edges with dusky bases on the inner pairs. Their tail is dusky with narrow olive edges to the feathers. Their throat is light gray or whitish gray, their breast light gray or grayish brown, and their belly and undertail coverts whitish.The other subspecies of the white-crested elaenia differ from the nominate and each other thus:E. a. griseigularis: paler upperparts than nominate, with less white on a shorter crest and a less distinct eyeringE. a. diversa: like griseigularis with a whiter throat, less distinct wing bars, and more contrast between the flanks and bellyE. a. urubambae: paler upperparts than nominate with paler lores, less prominent eyering, duller wing bars, and a pale yellow wash on the bellyE. a. modesta: duller overall than nominate, with no distinct lores and eyering contrast, less distinct wing bars, and pale edges on the inner flight feathers extending through what is dusky on the nominate
Both sexes of all subspecies have a dark brown iris, a black or dark gray bill with a pale base to the mandible, and black or dark gray legs and feet.
Distribution and habitat
The subspecies of the white-crested elaenia are found thus:E. a. griseigularis: from Nariño Department in far southwestern Colombia south through central Ecuador into northwestern Peru's Cajamarca DepartmentE. a. diversa:north-central Peru from Cajamarca south to Huánuco DepartmentE. a. urubambae: southeastern Peru's Urubamba River valley in Cuzco DepartmentE. a. albiceps: from Puno Department in far southeastern Peru into Bolivia as far as Cochabamba DepartmentE. a. modesta: breeds west of the Andes from Lambayeque Department in northwestern Peru south to Tarapacá Region in northern Chile and winters east of the Andes in Peru between San Martín Department and Madre de Dios DepartmentElaenias listed as white-crested by the SACC have been recorded as vagrants on the Falkland Islands but without subspecies identification, so they could have been what the IOC but not the SACC recognizes as the Chilean elaenia. The Chilean elaenia is highly migratory.
Note that the range map uses HBW taxonomy and so includes the extensive range of the Chilean elaenia, which reaches far east of the white-crested elaenia's range.
The white-crested elaenia's habitat has been studied for all subspecies except E. a. modesta, and it is assumed to have similar requirements to the others. They inhabit the edges of subtropical and temperate forest, the interior of more open woodlands and secondary forest, and scrublands. In many areas the species favors intermontane valleys that are drier than the slopes above. In elevation it ranges up to in Colombia, between in Ecuador, and between on the west slope and on the east slope in Peru.