White-crested Elaenia (Elaenia albiceps) [XC771764]
by Esteban Martinez Fredes from Gorbea, Caut\u00edn, Araucan\u00eda, Chile (dawn song)
White-crested Elaenia (Elaenia albiceps) [XC859173]
by Rosendo Manuel Fraga from below Chulina, near Charazani, La Paz, Bolivia (call, song)
Subspecies
Closely related to Small-billed Elaenia (Elaenia parvirostris), and vocally very similar and it has been suggested that they are conspecific, but they apparently do not hybridize across broad area of range overlap in Argentina. Subspecies chilensis has been treated as a separate species, although no significant vocal differences from others; this subspecies hybridizes locally with Small-billed Elaenia (Elaenia parvirostris) where ranges overlap in southern Bolivia (but not in north-western Argentina). Subspecies modesta sometimes treated as a separate species. Subspecies griseigularis possibly hybridizes with Sierran Elaenia (Elaenia pallatangae) in Ecuador.
The following 6 subspecies are recognised:
albiceps (D'Orbigny & Lafresnaye, 1837) - South-eastern Peru (south from Puno) south to north-western Bolivia.
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griseigularis Sclater, PL, 1859 - South-western Colombia south to north-western Peru (south to west Cajamarca).
diversa Zimmer, JT, 1941 - Andes of north-central Peru (Cajamarca south to Huánuco).
urubambae Zimmer, JT, 1941 - South-eastern Peru (near Cuzco).
modesta Tschudi, 1844 - Western Peru south to north-western Chile.
chilensis Hellmayr, 1927 - Breeds in Andes from southern Bolivia (Chuquisaca) south to Argentina (south to Catamarca and west Córdoba), thence south in lowlands to Tierra del Fuego; migrates north as far as Peru (possibly Colombia) and north-eastern Brazil (Pará and Bahia).
BirdLife International Species Factsheet