Broad-billed Hummingbird

The broad-billed hummingbird (Cynanthus latirostris) is a small, brilliantly coloured hummingbird of Mexico and the southwestern United States. Adults are about 8–10 cm long and weigh only 3–4 g. Males are metallic green with an intense blue throat and a broad red bill tipped in black. Females are greener above and greyish below, with a white line behind the eye and a darker bill.

Most of the population occurs in Mexico. The species reaches the United States mainly in southeastern Arizona and southwestern New Mexico, where it is a characteristic hummingbird of wooded desert canyons and riparian vegetation.

The limits of the broad-billed hummingbird have changed as isolated populations in the Cynanthus complex have been re-evaluated. Two populations formerly included within C. latirostris are now recognised as separate species: the Tres Marias hummingbird (Cynanthus lawrencei) of the Tres Marías Islands and the turquoise-crowned hummingbird (C. doubledayi) of southwestern Mexico.

The modern concept of C. latirostris therefore has a narrower Mexican range than in many older field guides and distribution accounts. Three subspecies remain within the species as currently defined.

Broad-billed hummingbirds occupy a wide range of habitats. In the United States they breed mainly along streams in mountain canyons with sycamores, cottonwoods and willows, generally at lower and middle elevations. In Mexico they occur from lowland thorn forest and tropical deciduous forest to mountain canyons, desert scrub, gardens and other flower-rich habitats.

After breeding, some birds move upslope to follow later flowering plants. The species readily uses human-modified areas where flowering vegetation, trees and suitable nesting cover remain available.

Nectar is the main energy source. Small insects and spiders provide essential protein and other nutrients, especially for growing young.

Broad-billed hummingbirds visit a wide variety of flowers, including agaves, ocotillo, desert willow and many other tubular blooms. The long tongue rapidly collects nectar while the bird hovers or briefly perches near flowers. Small insects and spiders are caught in the air or picked from foliage and spider webs.

Individuals may defend rich flower patches or feeders against other hummingbirds, although the intensity of defence changes with season and food availability.

Not all feeding areas are defended. Birds can also use a repeated circuit between scattered flowers, a strategy known as traplining, revisiting blooms as nectar is replenished.

Movement patterns vary across the range. Many birds in Mexico are resident or make local and altitudinal movements, while much of the population breeding in the United States moves south after breeding.

Post-breeding birds can also shift upslope or across the landscape to follow flowering peaks before longer-distance movements begin. This combination of migration and shorter seasonal movements helps the species track highly variable nectar resources.

The male takes no part in nest building, incubation or chick care. During courtship he hovers in front of a female and repeatedly swings from side to side in a pendulum-like arc, sometimes followed by a steep ascent and chase. Males may also display near one another in small, loose groups.

The female selects the nest site and builds a tiny cup from bark strips, grasses and leaves, lining it with soft plant fibres and binding the structure with spider silk. In the United States nests are often placed on thin, downward-hanging branches near streams. Two broods are often attempted in a season there, with nesting activity extending from about mid-April into August.

A clutch normally contains two white eggs, although three has been recorded. The exact incubation period in the wild is poorly documented but is estimated at about 15–19 days. The altricial young remain in the nest for roughly 20–26 days, and field observations indicate that the female may continue feeding them for another 7–14 days after fledging.

Broad-billed hummingbirds readily visit gardens and hummingbird feeders within their range. Flower-rich gardens can provide additional feeding opportunities, particularly in towns close to natural canyon and desert vegetation.

Native flowering plants and riparian vegetation provide a wider range of nectar sources and insects than feeders alone, as well as shelter and nesting sites.

The broad-billed hummingbird is classified as least concern on the IUCN Red List. It remains widespread and common across much of Mexico and extends regularly into the southwestern United States.

For 2012–2022, the eBird trend model estimated a range-wide increase of about 16.9%. Riparian vegetation and diverse native flowering habitats remain especially important for breeding and feeding birds.