Longuemare's sunangel (Heliangelus amethysticollis clarisse) is a hummingbird found in Venezuela and northeastern Colombia. It is closely related to the amethyst-throated sunangel, and species limits in this complex are unclear.
As defined here following the Handbook of the Birds of the World, this species comprises four subspecies: H. c. clarisse in the Colombian Andes from Norte de Santander to the latitude of Bogotá; violiceps in the Sierra de Perijá (only in Zulia in Venezuela); H. c. verdiscutus in southeastern Norte de Santander, Colombia, and southern Táchira, Venezuela; and H. c. spencei isolated in Mérida, Venezuela.
Originally spencei was described as a separate species and the other three species were considered subspecies of the amethyst-throated sunangel, whose undoubted populations live in Ecuador and Peru. Other arrangements have been suggested, but most authorities lump all of these groups with the amethyst-throated. A review by the American Ornithologists' Union's South American Check-list Committee stated that the situation is unclear and any decision is arbitrary until more data are available.
This bird is 9.4 cm (3.7 in) long (not including the bill) and weighs 5.3 grams, on average. The bill is short for a hummingbird—1.8 cm or 0.7 in long. The overall impression is of dark plumage.
Males are dark green above except that the crown is velvety black in verdiscutus and spencei, purplish in violiceps, and dull green in clarisse. They have a narrow, glittering blue "frontlet" above the bill. Behind the eye is a bold white spot. They have a glittering pinkish-purple throat above a white crescent crossing the chest, which in turn has a green lower border—glittering in violiceps and verdiscutus, shining in spencei. The rest of the breast and belly is shining dark green mixed with gray. The undertail coverts are white except in spencei, where they are buff. The tail is long and broad, bronze-green to blackish, with tiny white tips on the two outer feathers. Females resemble males but are duller, and white feather bases may show in the throat.
Vocalizations are little-known. Foraging spencei individuals give a "short, low-pitched, cricketlike trill" very similar to a call of the orange-throated sunangel. Among the vocalizations of verdiscutus is "a single, upward-inflected tsit" repeated about every half-second.
It inhabits forests, especially edges and openings, as well as brushy pastures and damp ravines with bushes; spencei prefers forest interiors. Its altitude range is 1800 to 3100 meters.
Three of the subspecies are common, spencei much less so.
Longuemare's sunangel generally flies and perches fairly low. Along forest edges with rich patches of flowers such as Psammisia and similar plants of the heath family, it behaves territorially. However, within forests, it flies along "trap-lines" from one flowering vine, epiphyte, or shrub (such as Palicourea) to the next. It feeds on nectar by hovering in front of flowers or clinging. In addition, it occasionally catches airborne insects in short flights. It feeds actively in the midst of mixed-species flocks when they pass.
Birds have been found in breeding condition from May to August. One nest of spencei was a downy cup on a small root exposed by an overhanging roadbank.