The Stripe-tailed Hummingbird (Eupherusa eximia) is a small hummingbird found in Costa Rica and western Panama. With an average body length of 9-10 cm (3.5-4 inches) and weight of 3-4 grams (0.1 oz), it is one of the smaller hummingbird species in Central America.
The Stripe-tailed Hummingbird gets its name from the bold black and white striped tail of the adult male. The tail is mostly black with a wide white band near the tip. From a distance, the tail appears all black. The female’s tail has less distinct striping.
The upperparts and head of the Stripe-tailed Hummingbird are a shiny green. The underparts are white with green sides. A white postocular spot is visible behind the eye. The long thin bill is straight and black. The legs and feet are brownish-black.
Males have a dark purple-black gorget (throat patch) which can appear black in low light. Females lack the gorget and are distinguished from the similar Crowned Woodnymph by the striped tail and all-dark bill. Immature birds resemble adult females but have buffy wingbars.
Distribution and Habitat
The Stripe-tailed Hummingbird is endemic to lower elevation tropical rainforests on the Caribbean slopes of Costa Rica and western Panama. Its range extends from eastern Costa Rica through Chiriquí and Bocas del Toro provinces in Panama.
This hummingbird inhabits the understory and edges of wet lowland forests, second growth, and plantations. It occurs up to 1200 m elevation but is most numerous below 800 m.
Food and Feeding
Like all hummingbirds, the Stripe-tailed Hummingbird has a specialized diet consisting of nectar, small insects, and spiders. It proboscises flowers using its long slender bill to lap up nectar. It also catches small insects in flight or gleans them from foliage.
This species visits a variety of brightly colored tubular flowers including heliconias, gingers, and red-flowering vines and trees. It prefers flowers with short corollas which match the length of its bill. The Stripe-tailed Hummingbird is important for pollination of these specialized rainforest plants.
Courtship and Breeding
The breeding season of the Stripe-tailed Hummingbird coincides with the rainy season from May to November. Males perform courtship flights to attract females. They fly in u-shaped patterns up to 100 feet in the air, dive suddenly, and then quickly ascend again while making buzzing sounds with their tail feathers.
The tiny cup-shaped nest is constructed by the female from plant down, spider silk, and lichens. It is attached to a low horizontal branch, vine, or fern frond, usually over water. The female lays two tiny white eggs which she incubates alone for 15-19 days.
The chicks are fed regurgitated food by the female. They fledge in about 20-26 days, quite a long growth period for such a small bird. The female continues care of the fledglings for another 2-3 weeks as they learn to forage on their own.
The Stripe-tailed Hummingbird has a relatively small geographic range but is common within its restricted habitat. Its population is estimated to number 50,000-500,000 individuals and is believed to be stable. Due to its large range and stable numbers, the Stripe-tailed Hummingbird is evaluated as Least Concern on the IUCN Red List of Threatened Species.
However, some localized threats from deforestation and habitat loss have been noted, especially near agricultural lands. Providing this species can remain adaptable to modified habitats such as plantations, its long-term outlook is expected to remain secure. Protecting remaining tracts of its specialized rainforest habitat will be important for conservation.
– The buzzing sound made with the tail feathers during the male’s courtship dive is produced by narrow, stiffened tail feathers scraping against each other.
– Small hummingbirds like this have very rapid metabolisms and heart rates. Their hearts can beat up to 1,200 times per minute and they breathe 250 times per minute while at rest!
– To conserve energy, they enter a state of torpor at night where their metabolic rate slows. Their body temperature drops from 40C to as low as 18C.
– Stripe-tailed Hummingbirds have short bills adapted for short-tubed flowers. They steal nectar by piercing flowers at the base rather than legitimately entering long tubed flowers.
– These tiny birds have been observed bathing in the spray of waterfalls as well as in rain collected in bromeliad plants. The baths help keep their feathers in good condition.
In summary, the Stripe-tailed Hummingbird is a diminutive and specialized rainforest species endemic to a small region of Central America. Its unique striped tail sets it apart from other hummingbirds. This delicate tropical bird serves as an important pollinator for its habitat and faces threats from deforestation in parts of its range. Ongoing conservation efforts aimed at protecting rainforest ecosystems will help ensure the future of this species and its vital ecological role.