Green-throated Tanager is a medium sized member of the genus Tangara, and resembles other Tangara species in body structure. This species is set apart by its opalescent green throat and straw-colored mantle, which is reflected in both common names used for this species. Sexes are dimorphic. The male has mostly yellow and jet black plumage, while the female has duller, mostly yellow and green plumage.
Green-throated Tanager forms a superspecies complex with Black-capped (T. heinei), Silvery (T. viridicollis), and Sira (T. phillipsi) tanagers (Graves and Weske 1987, Isler and Isler 1987). The most distinguishing feature of Green-throated Tanager is the straw like coloration, found on the mantle, breast, sides, and flanks (Ridgely and Tudor 1989, Hilty 2011). The females of these species, however, are slightly more difficult to distinguish. Females of T. argyrofenges are more distinctly tinged yellow overall than other species. This includes a more distinctly yellow straw-colored mantle and rump, as well as a more yellow-green tinge versus a dull green coloration seen in T. phillipsi, T. heinei, and T. viridicollis (Hilty 2011). Subadult plumage of T. argyrofenges is similar in pattern to T. viridicollis adult, but T. viridicollis has bolder and clearer sides and flanks (Restall et al. 2007).
Geographic overlap for these species is most prevalent between Green-throated Tanager and Silvery Tanager, both of which range through Ecuador, Peru and Bolivia. Although overlap is present, Green-throated Tanager is found only on the eastern slopes of the Andes (Isler and Isler 1987). The most distinguishing feature of these species is the color of their throats; Silvery Tanager has a copper colored throat, while the throat of Green-throated is a pale aquamarine to opalescent green color (Ridgely and Greenfield 2001b). Sira Tanager also is found in central Peru, but has a very restricted distribution, and Green-throated Tanager is absent or very uncommon at most localities from which Sira Tanager is reported.
The following description refers to the nominate T. argyrofenges, see also Geographic Variation.
Adult male: Mantle, uppertail coverts, sides and flanks are a pale, straw colored yellow, giving T. argyrofenges the English name of Straw-backed Tanager (Ridgely and Tudor 1989, Hilty 2011). Contrasting against this light coloration is the male’s jet black tail and upperwing coverts (Hilty 2011). This jet black coloration also is found on the crown and nape, wrapping narrowly around the rest of the side of neck and extending down to produce a black breast, belly, and undertail coverts (Hilty 2011). Set within the black coloration of the head, nape and breast are a pale aquamarine to opalescent green, which extends to the side of the bird’s head (Hilty 2011, Birdlife International 2014).
Adult female: Like the male, the female T. argyrofenges has a pale straw colored yellow mantle, rump and uppertail coverts, however these areas have a slightly greener tinge than that of the male (Birdlife International 2014). Females do not have any of the jet black coloration of the male, but rather a dusky green-brown crown and nape, green wings and tail, and a pale grayish green breast and belly that has a yellow tinge (Dunning 1982, Hilty 2011). The green coloration of the wings and tail is stronger than on other parts of the body (Dunning 1982). Similar to the male, the foreneck and side of head is a pale aquamarine to opalescent green color, however it is much duller on females (Hilty 2011, Birdlife International 2014).
Subadult: The subadult plumage has not been described in detail; however, it is similar to that of Silvery Tanager (T. viridicollis). Restall et al. (2007) describe a subadult plumage with greenish flight feather fringes and dusky cream coloration on the back (Restall et al. 2007).
Juvenile: Undescribed (Hilty 2011).
Tanagers that have been studied have either a Complex Basic Strategy or Complex Alternative Strategy (Ryder and Wolf 2009). However, most tanagers only molt once a year (Isler and Isler 1987), and this prebasic molt likely occurs after the breeding season (Isler and Isler 1987, Ryder and Wolfe 2009). Many species have been found to breed in subadult plumage (Isler and Isler 1987). In many species of Tangara, the preformative molt is partial (Ryder and Wolfe 2009). Although a subadult plumage is described for Tangara argyrofenges, more specific information on molt and its timing is not available for this species.
Iris: brown (Hilty 2011)
Bill: black (Hilty 2011)
Tarsi and toes: dark gray (Hilty 2011)
Total length: 12-13 cm (Dunning 1982, Isler and Isler 1987), average 12.5 cm (Clements and Shany 2001)
Body mass: 18-20 g; mean 19 g (n = 5, Isler and Isler 1987)