The Flame-crested Tanager is an average sized tanager. Males are mostly black with a distinct "flame-colored" red or reddish-orange crest, bordered with buff; the male also has a yellowish buff rump and narrow throat stripe. The female is much duller in plumage, with rufescent brown upperparts, and ochraceous buff underparts; the sides of the head are gray or grayish.
The scarlet crest of the male Flame-crested Tanager is distinctive, but can be difficult to see in the field (especially since this species typically forages high in the canopy). The Fulvous-crested Tanager (Tachyphonus surinamus) is similar, but has a crest that is fulvous (not red or red-orange), has a completely black throat, and usually shows white and chestnut along the side of the body.
The female Flame-crested Tanager is more nondescript and can be more difficult to identify. The female Fulvous-crested Tanager has a more extensively gray head, and has greener upperparts and yellower underparts. The female Flame-crested Tanager also can be confused with female shrike-tanagers (Lanio sp.). Shrike-tanagers are slightly larger overall, and have larger bills than do any species of Tachyphonus. Female shrike-tanagers also tend to be yellower, less rufescent.
Adult male: Mostly black with a broad, distinctly "flame-colored" (scarlet or orange) crest. Rump fulvous or yellowish buff. Narrow patch on center of throat yellowish buff. Lesser wing coverts and underwing coverts white. The underwing-coverts are stark white. During breeding season, males often display their underwing coverts and their crests (Isler and Isler 1987).
Adult female: Upperparts generally rufesecnt brown, more richly colored on the lower back and tail. Forecrown and side of head more or less gray. Underparts generally bright ochraceous buff, with a light buffy gray to whitish throat.
Juvenile: Little information; similar to adult female (Sick 1993).
Very little information. Wing molt was detected on three specimens from southern Venezuela in late February and early March, but another specimen from early March showed no signs of molt (Willard et al. 1991).
Iris: Dark brown (Willard et al. 1991)
Bill: Maxilla black; mandible of males black with a silvery gray base, mandible of females entirely gray (Willard et al. 1991)
Tarsi and toes: Black in males, gray in females (Willard et al. 1991)
Total length: 15 cm (Isler and Isler 1987)
Mass: mean (both sexes) 19.0 g (range 16.6 g-23.0 g; Isler and Isler 1999). Mean (five males) 18.8 g (range 18.0-21.0 g, SD ± 1.30; Willard et al. 1991); mean (two females) 18.3 g (18.0, 18.5 g; Wiillard et al. 1991).