The cinnamon-sided hummingbird (Amazilia rutila) is a small hummingbird species found in western and central Mexico. With an average body length of 9-10 cm and weight of 3-4 grams, it is a relatively petite hummingbird, though still larger than the bee hummingbird, the world’s smallest bird.
Physical Description
As the name suggests, the cinnamon-sided hummingbird has cinnamon-colored plumage on its flanks. The male has an iridescent reddish-bronze crown, throat, and belly, with a white breast in between. The female is similar but has greener plumage on top and whiter underparts. Both sexes have a straight black bill and white tips on the tail feathers.
In flight, these rapid fliers display a cinnamon panel on their sides and tail, alternating black and white stripes across the tail, and reddish feet. Their swift, hovered movement from flower to flower makes their colors appear blurred together.
Habitat and Range
Cinnamon-sided hummingbirds are found along the Pacific slope of Mexico, with their range extending from southern Sonora to Guerrero. They prefer tropical deciduous forests, woodland edges, gardens, and plantations.
These hummingbirds are altitudinal migrants, moving to higher elevations in the breeding season and descending to lower tropical areas for the winter. However, some populations may remain year-round in the tropical lowlands. Overall, cinnamon-sided hummingbirds can be found at elevations from sea level up to 5,900 feet.
Diet
Like all hummingbirds, cinnamon-sided hummingbirds feed on flower nectar and small insects. They use their specialized long bills and tongues to drink nectar while hovering at flowers. Some favorite nectar sources are salvias, lantana, honeysuckle, and coral vine.
These hummingbirds also hawk flying insects, capturing mosquitoes, gnats, spiders, and aphids in midair. They may also glean insects from leaves and branches. Aided by high metabolism, cinnamon-sided hummingbirds must consume half their weight in nectar and insects daily in order to survive.
Unique Adaptations
Cinnamon-sided hummingbirds display many anatomical adaptations that allow them to hover and thrive on their sugar-rich diet. Their wings beat around 50 times per second, rotating in a figure-eight pattern that provides the lift needed to stay suspended. Short, strong legs and feet allow them to perch very briefly.
Long, bifurcated tongues with forked tips can access nectar deep within curved flowers. A slender bill matches the shape of different blossoms. Since hummingbirds do not have a strong sense of smell, their vision guides them to favored flowers.
Hummingbird metabolism is the fastest of all vertebrates. Their rapid breathing, heartbeat, and food conversion power their high-energy lifestyles. Body temperature can drop into torpor at night to conserve energy.
Breeding
During breeding season, male cinnamon-sided hummingbirds set up breeding territories with plenty of flower resources. Their courtship displays involve flying in loops up to 130 feet in the air, then diving down past the female. If impressed, the female will mate with the male.
The female cinnamon-sided hummingbird builds a tiny cup-shaped nest out of plant down, spider webs, and lichen. It is attached to a downward hanging branch, often over water. She lays two pea-sized white eggs and incubates them for 14-19 days.
The chicks hatch altricial, or helpless, with closed eyes and very few feathers. They are reliant on their mother, who feeds them regurgitated insects and nectar. After about 20-26 days, the young hummingbirds fledge from the nest. By two months old, they reach sexual maturity.
Threats and Conservation
Habitat loss in Mexico has impacted cinnamon-sided hummingbird populations. Conversion of their tropical forests to agriculture and development has reduced breeding areas. Urbanization also encroaches on natural habitat.
However, these adaptable hummingbirds have learned to thrive in human-altered environments. They are common in parks and gardens, provided some native plants and flowers are available for food. Backyard sugar water feeders also supplement their diet.
While still relatively numerous, maintaining habitat corridors between isolated fragments of remaining tropical forest will be important for connectivity of cinnamon-sided hummingbird populations. Protecting areas with high densities of favored flowering plants can also help safeguard this energetic pollinator.
Summary
With bright plumage in the males, specialized adaptations like hovering flight and nectar-lapping tongues, and one of the fastest metabolisms of all birds, the cinnamon-sided hummingbird is a unique species. Though development has reduced their Mexican tropical forest habitat, they continue to frequent gardens, parks, and anywhere flower nectar is plentiful. Maintaining habitat connections and food sources will allow these energetic hummingbirds to continue buzzing through the forests they call home.