The Mexican Sheartail (Doricha eliza) is a small hummingbird found in Mexico and parts of the southwestern United States. With an average body length of 7-8 cm and weight of 2-3 grams, it is one of the smallest hummingbird species in North America. The male has a slender bill and bright green plumage on its head, back and underside, with a metallic purplish-pink throat patch (gorget). The female is similar but lacks the vibrant gorget, instead having pale white tips on her tail feathers.
Range and Habitat
The Mexican sheartail inhabits dry scrubland, woodland edges, canyons and mountain slopes across central and western Mexico. Its breeding range extends north into Arizona, New Mexico and Texas in the United States. It occupies elevations from sea level up to around 1800 m. The habitat consists of arid landscapes dotted with flowering plants and small trees. Agaves and ocotillos are important food sources.
Migration
The northern populations of Mexican sheartails are migratory. They breed in the southwest US border states during spring and summer, before migrating back to Mexico in fall. The timing of migration seems to coincide with the blooming cycles of their favorite agave plants. Some southern populations in Mexico appear to be resident year-round.
Description and Identification
The Mexican sheartail gets its name from the distinctive forked shape of the female’s tail. The male has a slightly forked tail as well, along with iridescent reddish-pink feathers on his throat (gorget). His upperparts and flanks are bright metallic green, while the underparts are grayish white. The female lacks the male’s gorget and has light white tips on the outer tail feathers. Both sexes have a straight black bill adapted for feeding on nectar at flowers.
The sheartail’s small size, green back, and forked tail distinguish it from other North American hummers. The magnificent hummingbird is the only other fork-tailed species, but the male magnificent has a much more extensive purple gorget. Other small hummers like the Calliope, rufous and broad-tailed lack the forked tail.
Diet and Behavior
Like all hummingbirds, the Mexican sheartail feeds on nectar from flowering plants such as salvias, penstemons, and various cacti. They use their long, extendable tongues to lap up the sweet nectar while hovering in front of flowers. They also take small insects such as gnats, aphids, and spiders to obtain proteins.
The sheartail is an aggressive and territorial bird despite its tiny size. Males defend feeding territories from other males, and may mate with several different females over the course of a breeding season. Their courtship displays include aerial flights and dives to impress females.
Nesting
The female sheartail builds a small cup-shaped nest by collecting plant down, spider webs and lichens, binding them together with silk from spider webs or flower buds. The nest is only about 2 inches wide and is attached to a vertical twig or stem in a shrub or tree.
She lays two tiny white eggs and incubates them for about two weeks. Once hatched, the chicks are fed regurgitated insects and nectar by the female. They fledge in 3-4 weeks, and reach sexual maturity by their first year.
Threats and Conservation
Major threats to the Mexican sheartail include habitat loss from development, grazing, and reduction of flowering plants. Climate changes that alter bloom cycles also impact their food availability. Use of pesticides and invasive species are additional problems.
Providing protected wildlife corridors and preserving scrub habitats helps protect connectivity between sheartail populations. Limiting grazing intensity and maintaining native flowering plants are other conservation measures. The species is currently classified as Least Concern by the IUCN Red List, but localized declines have occurred and ongoing conservation efforts are needed.
In summary, the Mexican sheartail is a diminutive and colorful hummingbird adapted to the arid landscapes of Mexico and the southwestern US. Their migratory habits, territorial behavior and unique forked tail make them fascinating to observe in the wild or backyard. Maintaining connectivity of their dry scrub habitats will ensure this delicate species continues brightening the region with their emerald and pink plumage.