About Elaenia frantzii Lawrence, 1865
This species is commonly called mountain elaenia, with the scientific name Elaenia frantzii Lawrence, 1865. The mountain elaenia measures 14 to 15 cm (5.5 to 5.9 in) long and weighs about 14 to 24 g (0.49 to 0.85 oz). It is a small to medium-sized elaenia with a rounded crest, and sexes of all subspecies share identical plumage. All adult individuals of all subspecies have a brown iris, a dark brown upper mandible, an orange lower mandible with a dark brown tip, and dark brown legs and feet. Adult nominate subspecies (E. f. frantzii) have a brownish olive head with lighter cheeks, a thin very pale olive eyering, and a mostly hidden white crown patch. Their upperparts are grayish olive. Their wings are mostly dusky, with pale olive or olive-yellow edges on flight feathers; the tips of their wing coverts are yellowish olive and form two distinct bars on the closed wing. Their tail is grayish brown with pale olive-green feather edges. Their chin, throat, upper breast, and flanks are pale yellowish olive, while their lower breast, belly, and undertail coverts are pale straw yellowish. Juvenile mountain elaenia are similar to adults, but are browner on the upperparts and paler on the underparts. Subspecies E. f. ultima has browner, less greenish olive upperparts and darker, more olivaceous underparts than the nominate subspecies. Subspecies E. f. pudica is smaller than the nominate, with darker upperparts and paler underparts. Subspecies E. f. browni is smaller than E. f. pudica, with paler, more greenish olive upperparts. The mountain elaenia has a disjunct distribution, with each subspecies occupying a separate range. E. f. ultima is found from Chiapas in southern Mexico south through Guatemala, El Salvador, and Honduras into northwestern Nicaragua. E. f. frantzii is found in southern Nicaragua, and after a gap in range, from western Costa Rica to central Panama. E. f. browni is found in two isolated areas: the Sierra Nevada de Santa Marta in northern Colombia, and the Serranía del Perijá that straddles the Colombia-Venezuela border. E. f. pudica is found in Colombia's Western and Central Andes, the Andes of western Venezuela, and the Venezuelan Coastal Range. Older field guides and publications do not include Chiapas in the mountain elaenia's range, as the species was not confirmed to occur there until 2016. Similarly, earlier range maps do not extend the species' range to central Panama, where records of the species have existed starting in the mid-2010s. The two Central American subspecies of mountain elaenia primarily inhabit cloudforest, but also occur in semi-open pine-oak forest and at the edges of denser forest. In South America, the species primarily inhabits open woodlands, scrublands, and pastures with scattered trees; it also occurs in some coffee plantations and cloudforest in Colombia. Across its range, the mountain elaenia occurs at different elevation ranges: 1,250 to 2,500 m (4,100 to 8,200 ft) in Central America; 600 to 3,000 m (2,000 to 9,800 ft) in Colombia; 1,200 to 2,900 m (3,900 to 9,500 ft) in the Venezuelan Andes; and 1,200 to 2,250 m (3,900 to 7,400 ft) in the Serranía del Perijá.
