King Vulture is a large, heavy bodied vulture with an approximate wingspan of 1.5 m. The plumage of adults is predominantly white, with black lower back and rump, tail, and flight feathers. There also is a dusky gray to blackish ruff at the base of the neck. One of the most distinctive features of the adult is the brightly colored bare skin of the head and neck, which has intricate skin folds, vivid colors of reds, oranges, yellows, and purple, with a yellow or orange-red carbuncle at the base of the bill and a pink pendent crop. The iris is white, and the bill is orange red with a dark base. King Vulture takes four to five years to reach the adult plumage. The juvenile is all sooty black; over successive years the plumage gradually transitions into the definitive plumage. Sexes are largely similar although males are on average slightly larger.
Adult King Vulture is almost unmistakable. Wood Stork (Mycteria americana) and Maguari Stork (Ciconia maguari) also are white with black flight feathers, but are larger than the vulture, with a long neck and very long bill, and very long tarsi that are extended in flight. Juvenile King Vultures could be confused with other South American vultures. The underwing coverts of juvenile King Vulture are mottled with white; the underwing coverts of other dark bodied vultures are entirely black. Black Vulture (Coragyps atratus) is smaller and even shorter tailed, and the wings are less square with whitish primary patches. Lesser Yellow-headed Vulture (Cathartes burrovianus) and Turkey Vulture (Cathartes aura) have longer, narrower wings and tail, with two-tone underwings and a marked dihedral wing angle when gliding or soaring. Greater Yellow-headed Vulture (Cathartes melambrotus) flies on level wings like King Vulture, but has a longer tail and distinctively patterned flight feathers. Andean Condor (Vultur gryphus) is much larger, with a different flight shape, and a white ruff.
The following description primarily is based on Wetmore (1965), Howell and Webb (1995), Eitniear (1996) and Ferguson-Lees and Christie (2001):
Adult: Head and neck bare (see Bare parts). Body plumage white, with a buffy or creamy tinge on the back, scapulars, and wing coverts except for a ruff of dark gray feathers around the lower neck, and for black lower back, rump, and uppertail coverts. Rectrices black. Remiges black. Sexes similar, with males averaging slightly larger and having larger, more pendent carbuncle at base of bill (Houston 1994, Ferguson-Lees and Christie 2001).
Nestling: Young nestlings are covered in white down except for head and feet (Ramo and Busto 1988, de Carvalho Filho et al. 2004).
Juvenile: Uniformly sooty black, with some whitish mottling on lower underparts and on underwing coverts.
First basic plumage: Acquired after a prolonged molt. Ruff and upperparts slate gray. Underparts white, with some dusky mottling.
Second basic plumage: Underparts pure white; upperparts (wing coverts, scapulars, and, eventually, back) mottled with white.
Third basic plumage: Similar to adult, but wing coverts mottled with dusky.
Fourth basic plumage: Attains definitive plumage
Molt likely similar to other cathartid vultures. The pterylosis is detailed in Fisher (1943).
Iris: Adult- white irides; juvenile – brown, and immature yellow-gray to whitish.
Orbital ring: red
Bill: Adult – orange-red with black base; juvenile – black with reddish tinges.
Tarsi and toes: At all ages legs are gray or dusky and yellow; and frequently appear whitened by defecation. Hatchling tarsi and toes pink (de Carvalho Filho et al. 2004).
Individuals have unique footprints (Eitniear 1989).
Head: Adult – rear crown, bare neck, and lobed carbuncle at base of bill predominantly yellow and orange-red; rest of head contrastingly dark, black bristled on top, with violet or mauve to dirty blue-gray pendent lore-lobes and corrugated cheeks; bare pinkish pendent crop. Skin appears wrinkled and folded. Hatchling head pink (de Carvalho Filho et al. 2004) and by 2-3 weeks of age the head was described as naked and black (Ramo and Busto 1988). Juvenile head black with some orange or reddish tinges on neck and rudimentary carbuncles. Second/third year – head and neck partially orange and red and carbuncles are developing. Third-fourth year – head colors stronger. Fourth/fifth year – head colors and carbuncles increasingly as adult (Ferguson-Lees and Christie 2001).
Bare parts data primarily from Houston (1994) and Ferguson-Lees and Christie (2001).
Total length: 71-81 cm (Ferguson-Lees and Christie 2001), 71-81.5 cm (Howell and Webb 1995)
Wingspan: 170-200 cm (Ferguson-Lees andand Christie 2001), 180-198 cm (Houston 1994.
Linear measurements (from Wetmore 1965):
male (n = 10)
wing length: mean 503 mm (range 490-525 mm)
tail length: mean 215 mm (range 207-227 mm)
bill length (culmen from cere): mean 35.2 mm (range 32.1-38.8 mm)
tarsus length: mean 98.6 mm (range 93-103 mm)
female (n = 2)
wing length: mean 493 mm (range 490-497 mm)
tail length: mean 215 mm (range 213-217 mm)
bill length (culmen from cere): mean 33.7 mm (range 33.5-34.0 mm)
tarsus length: mean 103 mm (range 100-106 mm)
Measurements of hatchlings were made at a nest in Brazil (de Carvalho Filho et al. 2004) – at hatching (length beak to tail feathers 13.9 cm); 22 days (length 33 cm; mass 1000 g; 43 days (length 50 cm; mass 1960 g); 110 days (near fledging; length 72.7 cm; mass 3490 g).
Mass: mean 3400 g (range 3100-3700 g, n = 7, sex not determined; Wallace and Temple 1987)