Emerald tanager

Illustrated by John Gerrard Keulemans.

The emerald tanager was first described as Calliste florida by the English ornithologists Philip Sclater and Osbert Salvin in 1869, based on a female specimen from Costa Rica that was collected by Julian Carmiol.[3] The name of the genus, Tangara, comes from the Tupí word tangara, meaning "dancer". The specific name florida comes from the region of Florida.[4] Emerald tanager is the official common name designated by the International Ornithologists' Union (IOU).[5]

The emerald tanager is one of 27 species in the genus Tangara, a Neotropical genus of tanagers.[5] According to a 2004 study of mitochondrial DNA by Kevin Burns and Kazuya Naoki, it belongs to a species group that includes the blue-whiskered tanager, green-and-gold tanager, golden tanager, silver-throated tanager, saffron-crowned tanager, golden-eared tanager, and flame-faced tanager. Out of these, it is most closely related to the silver-throated tanager. The following cladogram shows phylogenetic relationships within the species group based on the above study:[6]

The emerald tanager is recognized as monotypic by the IOU.[5] However, some authorities recognize populations from eastern Panama to Colombia and northwestern Ecuador as being a distinct subspecies, T. f. auriceps.[7]

The emerald tanager is a medium-sized tanager with a length of 10.6–13 cm (4.2–5.1 in) and a mass of 18–20.5 g (0.63–0.72 oz). Both sexes are similar in appearance, but the species shows slight sexual dimorphism, with females being duller and having yellow-green instead of yellow on the head. It may be confused with the glistening-green tanager but can be told apart by its less intense plumage. It is also similar to the blue-whiskered tanager but can be distinguished by the latter's black face and throat and turquoise cheeks.[7]

Adults males are mostly bright light green, with black streaking on the upperparts. The loral area, the base of the bill, and chin, along with the auricular patch, are also black. The center and rear of the crown are dark yellow, while the rest of the crown, the region around the eye, and the band across the back of the neck are yellowish-green. The upper back is black, while the lower back, rump, and uppertail coverts are dark yellow. The wings are black and green. The underparts are mostly light green, while the center of the belly and the undertail coverts are light yellow. The iris is brown, the bill is black and the feet are bluish-gray. Immatures resemble adult females, while juveniles are much duller. Juvenile males gain plumage similar to that of adult females after their first molt, while they gain adult male plumage after a second molt that occurs after their first breeding season.[7]

The emerald tanager is found from southern Costa Rica to northern Ecuador; through Panama and Colombia. It may also be found in extreme southern Nicaragua. There are two disjunct populations, separated by an area between Panama and the San Juan River. Throughout its range, the emerald tanager is commonest at elevations of 500–900 m (1,600–3,000 ft) but is found at elevations of up to 1,200 m (3,900 ft) in Ecuador and as low as 100 m (330 ft) in Colombia. The average elevation inhabited is highest in the north of the range and is the lowest in the south.[7]

The emerald tanager inhabits humid lowland forest, montane evergreen forest, and secondary forest. It is usually found in the canopy and rarely strays to the forest floor. It has also been observed in lone fruiting trees or shrubs next to forests. It prefers forested habitats to semi-open ones.[7]

The species has a generation length of 3.26 years.[1]

The emerald tanager is listed as being of least concern by the International Union for Conservation of Nature (IUCN) on the IUCN Red List due to its sufficiently large range and a lack of significant population decline. However, its population, which is thought to be between 40,000 and 499,999 mature birds, is currently decreasing.[1] The species is threatened by habitat destruction and is already suffering locally due to deforestation. Habitat destruction is an especially acute problem in areas that have steep changes in elevation, as it could lead populations becoming isolated and a reduction in genetic diversity (the variety in a population's genetic characteristics).[7]