The Black-eared Fairy Hummingbird (Heliothryx aurita) is a small hummingbird found in Central and South America. With an average body length of 5-6 cm and weight of 2-3 grams, it is one of the smallest birds in the world. Despite its tiny size, the Black-eared Fairy is known for its feisty behavior and remarkable flying skills.
The Black-eared Fairy gets its name from the black or dark grey ear-coverts found on the sides of the head behind the eyes. The upperparts of the body are mostly golden green. The underparts are white with green spotting on the sides. The long thin bill is straight and black. The legs and feet are also black. The male has a purple-red throat called a gorget. Females lack the colored gorget. Juveniles resemble adult females but with some buffy streaking below.
There are eight recognized subspecies of the Black-eared Fairy which differ slightly in size and coloration based on their geographic range from Mexico to Bolivia. For example, H. a. aurita found in Costa Rica is the nominate or original subspecies with bright green upperparts. H. a. nigriceps from Mexico has duller bronze-green upperparts.
Habitat and Range
The Black-eared Fairy inhabits tropical lowlands, foothills and lower mountain slopes. It prefers edges and clearings in humid evergreen forest, semi-open areas, gardens, and plantations. Its elevational range is from sea level up to 1500 m.
The overall range extends from southern Mexico through Central America to western Ecuador, northern Venezuela and just into northwestern Colombia. However, the range is not continuous and becomes localized or patchy in places like El Salvador and Colombia. The species is considered a year-round resident within its range.
Diet and Feeding
Like all hummingbirds, the Black-eared Fairy feeds mainly on nectar taken from colorful tubular blossoms. Some favorite nectar sources include plants in the Heliconia family as well as epiphytic Ericaceae shrubs and trees in the genus Cavendishia. The long bill allows access to nectar of long corolla flowers. While hovering or perching near flowers, the bird uses its extensible tongue to lap up nectar.
The Black-eared Fairy also consumes small insects and spiders which are captured in flight or picked off vegetation. This provides supplemental protein and nutrients to the diet. A portion of each day is spent darting through swarms of tiny insects.
The Black-eared Fairy Hummingbird has evolved several key adaptations related to its tiny size and nectar-feeding lifestyle:
– A very fast metabolic rate with high oxygen needs and a rapid heart rate around 500 beats per minute while resting. This provides the energy needed for hovering flight and constant motion.
– Rotating wings that can beat up to 70 times per second, allowing the bird to fly backwards, upside down, and in every direction.
– Excellent color vision and expansive fields of view to detect colorful flowers.
– An extremely light skeleton and strong muscle mass making up 25% of their total body weight (compared to just 7% in larger birds).
– A long slender bill perfectly shaped to access nectar from specialized flowers.
– A tongue that extends past the end of the bill to lap up nectar while hovering. The tongue even has a forked tip to collect more nectar.
– Ability to enter a hibernation-like state each night called torpor to conserve energy.
Behavior and Reproduction
The Black-eared Fairy lives solitarily and can be quite territorial. Males use aerial displays, chasing dives, and vocalizations to defend nectar-rich flowering plants. They are known for aggressively chasing away intruders including larger birds.
Courtship displays include flying in wide arcs above a female while calling continuously. Breeding occurs in the spring and summer months corresponding with peak flower blooming. The tiny cup-shaped nest is constructed using plant down, lichen, and spider webs on top of a low horizontal branch or tree fern.
The female lays just two pea-sized white eggs. She incubates the eggs alone for about 16-19 days until hatching. The chicks are fed regurgitated insects and nectar by the female and fledge in just 18-22 days. This is an unusually short time compared to larger bird species.
Threats and Conservation
While still relatively common, the Black-eared Fairy Hummingbird is classified as a Species of Least Concern by the IUCN. Populations appear to be decreasing in Central America primarily due to habitat destruction. Capturing wild hummingbirds for the cage bird trade also poses a threat.
Across its range, the species adapts readily to gardens, parks, and farms providing flowers are available. But it remains reliant on intact tropical forest habitats. Protecting moist evergreen forest environments will be key to the long-term survival of Black-eared Fairy Hummingbirds. Ecotourism focused on observing hummingbirds can also raise awareness and funding for conservation when responsibly managed.
With their glittering colors, hovering flight, and pugnacious behavior, the Black-eared Fairy Hummingbird is truly a magical feathered jewel of Central and South America’s forests. Their unique adaptations and vital pollination services make them an integral part of healthy tropical ecosystems. Continued study and protection of these smallest of birds will help ensure their enduring place in the natural world.