About Lathrotriccus euleri (Cabanis, 1868)
Euler's flycatcher (Lathrotriccus euleri) measures 12.7 to 13.5 cm (5.0 to 5.3 in) in length and weighs 9 to 13.8 g (0.32 to 0.49 oz). Males and females have identical plumage. For the nominate subspecies L. e. euleri, adults have warm olive-brown coloration on the crown, nape, and cheeks. They have a whitish eye-ring and a faint pale stripe above the lores. Most of their upperparts are olive-brown, with a brown rump. Their wings are dusky, with pale buff tips on the coverts that form two distinct wing bars. The secondaries and tertials have pale buffy-brown edges, and their tail is dusky. Their throat is grayish white, their breast has a brownish olive wash, and their belly ranges from pale yellow to white. Other subspecies differ from the nominate and from each other as follows: L. e. flaviventris is similar to the nominate. L. e. lawrencei has more olive upperparts than the nominate, along with a whitish throat, a drabber gray breast, and a white belly. L. e. bolivianus has more olive upperparts than the nominate but less olive than L. e. lawrencei, with a pale olive-gray breast and a slightly less yellow belly than the nominate. L. e. argentinus has a drabber gray breast than the nominate, with a whitish throat and white belly. All subspecies of Euler's flycatcher have a dark iris, a black maxilla, a dull pinkish or orangish pink mandible, and blackish brown legs and feet. The subspecies have separate distribution ranges: L. e. flaviventris is found on Grenada, and is possibly extinct. L. e. lawrencei occurs in the Eastern Andes of Colombia, the Andes and Coastal Ranges of western and northern Venezuela, Trinidad, and locally in the Guianas. L. e. bolivianus ranges from Amazonas and Bolívar states in southern and eastern Venezuela, south through eastern Ecuador and eastern Peru into northwestern Bolivia, and east across much of Amazonian Brazil. L. e. argentinus is found in central and eastern Bolivia, northern and northeastern Argentina, and Paraguay; during migration it occurs in eastern Peru and eastern Brazil. The nominate subspecies L. e. euleri lives in southeastern Brazil, northeastern Argentina, and Uruguay; during migration it occurs in Peru, Bolivia, and Brazil. Euler's flycatcher inhabits moist to humid primary and secondary forest and woodlands in tropical and lower subtropical zones. It prefers the lower levels and edges of these habitats. Its elevation range varies by location: it occurs from sea level up to 1,500 m (4,900 ft) in Brazil; in Venezuela, it is found below 1,600 m (5,200 ft) north of the Orinoco River and below 1,000 m (3,300 ft) south of the river; it reaches 800 m (2,600 ft) in Colombia, 1,300 m (4,300 ft) in Ecuador, and 1,600 m (5,200 ft) in Peru.
