Bee hummingbird

Description

The bee hummingbird is the smallest living bird. Females weigh 2.6 g (0.092 oz) and are 6.1 cm (2.4 in) long, and are slightly larger than males, with an average weight of 1.95 g (0.069 oz) and length of 5.5 cm (2.2 in). Like all hummingbirds, it is a swift, strong flier.

The male has a green pileum and bright red throat, iridescent gorget with elongated lateral plumes, bluish upper parts, and the rest of the underparts mostly greyish white. The male is smaller than the female. The female is green above, whitish below, with white tips to the outer tail feathers. Compared to other small hummingbirds, which often have a slender appearance, the bee hummingbird looks rounded and plump.

Female bee hummingbirds are bluish green with a pale gray underside. The tips of their tail feathers have white spots. During the mating season, males have a reddish to pink head, chin, and throat. The female lays only two eggs at a time, each about the size of a coffee bean.

The brilliant, iridescent colors of the bee hummingbird's feathers make the bird seem like a tiny jewel. The iridescence is not always noticeable, but depends on the viewing angle. The bird's slender, pointed bill is adapted for probing deep into flowers. The bee hummingbird feeds mainly on nectar, and an occasional insect or spider, by moving its tongue rapidly in and out of its mouth. In the process of feeding, the bird picks up pollen on its bill and head. When it flies from flower to flower, it transfers the pollen. In this way, it plays an important role in plant reproduction. In one day, the bee hummingbird may visit 1,500 flowers.

Diet

The bee hummingbird has been reported to visit 10 plant species, nine of them native to Cuba. These flowers include Hamelia patens (Rubiaceae), Chrysobalanus icaco (Chrysobalanaceae), Pavonia paludicola (Malvaceae), Forsteronia corymbosa (Apocynaceae), Lysiloma latisiliquum (Mimosaceae), Turnera ulmifolia (Passifloraceae), Antigonon leptopus (Polygonaceae), Clerodendrum aculeatum (Verbenaceae), Tournefortia hirsutissima (Boraginaceae), and Cissus obovata (Vitaceae). They occasionally eat insects and spiders. In a typical day, bee hummingbirds will consume up to half their body weight in food.

Habitat and distribution

The bee hummingbird is endemic to the entire Cuban archipelago, including the main island of Cuba and the Isla de la Juventud in the West Indies. Its population is fragmented, found in Cuba's mogote areas in Pinar del Rio province and more commonly in Zapata Swamp (Matanzas province) and in eastern Cuba, with reference localities in Alexander Humboldt National Park and Baitiquirí Ecological Reserve (Guantanamo province) and Gibara and Sierra Cristal (Holguin province).

Breeding

The bee hummingbird's breeding season is March–June. They lay up to two eggs at a time. Males in the “bee” hummingbird clade court females with sound from tail‐feathers, which flutter during display dives.

Using bits of cobwebs, bark, and lichen, the female builds a cup-shaped nest that is about 2.5 cm (0.98 in) in diameter. Nests have been built on single clothespins. She lines the nest with soft plant fibers. There she lays her eggs, which are no bigger than peas. She alone incubates the eggs and raises the young.

Coevolution with flowers

The bee hummingbird interaction with the flowers that supply nectar is a notable example of bird–plant coevolution with its primary food source (flowers for nectar).