Lesser Violetear is a medium sized hummingbird with a black, very slightly curved bill of medium length (for a hummingbird). The plumage primarily is iridescent green, with a broad patch of violet on the side of the head. The rectrices are greenish blue, with a blackish band near the tip. See Similar Species.
Lesser Violetear is similar to Mexican Violetear (Colibri thalassinus), of northern Central America (Mexico to Nicaragua), but these two species are allopatric. Furthermore, Mexican Violetear has a bright blue upper breast and often has some blue on the chin; the underparts of Lesser Violetear are entirely glittering green, with no blue. No similar species occurs with Lesser Violetear in the northern portion of its range, in Costa Rica and Panama. In the Andes, Lesser Violetear overlaps broadly, from Venezuela south to Argentina, with Sparkling Violetear (Colibri coruscans). Sparkling Violetear is much larger; has a violet blue chin and a large violet blue patch on the belly; and the body plumage often is a bluer shade of green. In Bolivia and Argentina, Lesser Violetear also overlaps locally with White-vented Violetear (Colibiri serrirostris). White-vented Violetear is similar to Lesser in having a green throat and breast, but is larger than Lesser Violetear, and has a white lower belly and undertail coverts.
The following description is based on Ridgway (1911):
Adult, male: Upperparts generally metallic green or bronze green. The rectrices are more bluish green (median rectrices more bronzy), crossed by a broad subterminal blue black band. Remiges dusky or dark brownish slate, very faintly glossed with purplish. Suborbital and auriculars areas dark metallic violet blue; this blue does not extend to the lores. Chin and throat bright metallic green; breast and belly duller metallic green. Undertail coverts buff, centers of the feathers more or less green.
Adult, female: Similar to adult male, but slight duller in color.
Immature: Similar to female, but feathers of upperparts are margined or tipped with rusty brown or cinnamon; similar pattern on the feathers of the underparts, but the pattern of terminal feather margins is less distinct. Also, the green of the chin and throat is duller.
Apparently undescribed in Lesser Violetear.
Iris: dark brown
Toes: dusky grayish brown
Data from Ridgway (1911).
Total length: 9.7 cm (Hilty and Brown 1986), 9.9 cm (Hilty 2003), 10.5 cm (Stiles and Skutch 1989)
Linear measurements (mm) of Colibri cyanotus (Wetmore 1968)
||culmen (from base)
Mass: male, mean 5.3 g (n = 2: 5.1, 5.47 g; Panama, Hartman 1954); female, 4.8 g (n = 1; Panama, Hartman 1954); unsexed, 5 g (n = 1; Peru, Weske 1972)