The sword-billed hummingbird (Ensifera ensifera) is a fascinating and unique species of hummingbird found in the Andes Mountains of South America. With its extremely long bill that can reach up to 10 centimeters (4 inches) in length, the sword-billed hummingbird has adapted to feed on plants with long, tubular flowers that few other pollinators can access. In this comprehensive article, we will explore the key features, behavior, habitat, diet, reproduction, conservation status and interesting facts about this extraordinary hummingbird.
Physical Description
The most striking feature of the sword-billed hummingbird is, without a doubt, its remarkably long, slender bill which is the longest of any extant bird relative to its body size. The bill accounts for around half of the bird’s total length, averaging 9-10cm but reaching as long as 11cm in the largest males. It is slightly decurved and very thin, ending in a fine point which allows the bird to efficiently feed on nectar from long tubular flowers. The body itself is fairly small and slender, reaching about 8-10cm in length and 2-4g in weight.
Males are mostly green on the head, back and wings with a greyish-white underside. The most colorful feature is the bright green gorget (patch of iridescent feathers on the throat). Females are similar but less vibrant, with white speckles on the throat and chest. The tail is fairly long, forked and edged with rufous-brown bars. Juveniles resemble adult females but with buffy bars instead of rufous-brown.
Habitat and Distribution
The sword-billed hummingbird is endemic to the Andes Mountains of South America. Its range stretches from Venezuela to Bolivia between elevations of 2500-5000m. It resides in cloud forest, elfin forest, montane scrub and paramo grassland habitats within this range. Areas with abundant flowers from the passionflower genus provide ideal feeding grounds. Outside of the breeding season, it may descend to lower elevations.
Unique Adaptations
The bill of the sword-billed hummingbird, while extreme, is an excellent example of evolution through natural selection. By developing an elongated, specialized bill, this species is able to target food sources inaccessible to most other pollinators. When feeding, the hummingbird perches next to the flower and uses its bill like a sword, swinging it back and forth to access nectar at the base of long tubular corollas. This allows it to tap into a niche food source.
Another neat adaptation is ridges on the inside edge of the bill which help guide nectar upwards via capillary action. Since the bill is so long, this helps ensure the nectar reaches the throat instead of slowly dripping out the end. The tongue itself is also bifurcated to match the shape of the flowers.
Diet
As one may predict, the sword-billed hummingbird feeds almost exclusively on nectar from tubular flowers with long corollas. Some of its favorite flowers come from the passionflower genus, especially Passiflora mixta. It uses its specialized bill to target flowers ignored by most other pollinators.
This species can feed while hovering but also perches to feed. It supplements its diet with small insects like flies and spiders. The proportion of nectar vs insects in the diet varies by season, with more insects during breeding season to obtain protein.
Behavior and Ecology
The sword-billed hummingbird is solitary and territorial. Males establish breeding territories with plentiful flower resources which they aggressively defend from intruders, even other larger hummingbird species. Their long bills come in handy during aggressive encounters, with males regularly engaging in fencing matches crossed at the tips.
This species has some interesting courtship displays. Males fly in U-shaped or figure-eight patterns up to 100m in the air to impress females. They produce a fast chipping call during these aerial shows. Males also vocalize to defend territories or when perched near females.
Given their high-altitude habitat, sword-billed hummingbirds are well adapted to cold. They can slow their heart rate and metabolism by up to 50-70% at night to conserve energy. They also enter torpor on cold nights.
Reproduction
The breeding season for sword-billed hummingbirds coincides with peak flower availability between October to March. Males do not assist with building the nest, so the female alone constructs a small cup nest on high-altitude cliff ledges or outcrops using feathers, moss and spider webs.
She lays just two tiny white eggs in the nest which she incubates for about 16-19 days. Chicks hatch with only a stub of a bill which gradually elongates as they develop. The female alone provides care and feeds the chicks with nectar and insects. After another 20-26 days, the young leave the nest. Not much else is known about the early life stages of wild birds.
Conservation Status
The sword-billed hummingbird has a relatively widespread distribution but its montane forest habitat has declined over 30% in the past 50 years. Its global population is estimated between 10,000-100,000 individuals and is suspected to be in moderate decline. For these reasons, the IUCN Red List categorizes this species as Near Threatened.
Major threats include deforestation and habitat degradation from logging, agriculture, and grazing. As forests are cleared, floral resources decline. Climate change poses another threat by shifting suitable habitat upwards in elevation, reducing available range. Eco-tourism and recreation activities also disturb sensitive breeding areas.
Interesting Facts
– The sword-billed hummingbird has the longest bill relative to its body size of any bird. At up to 11 cm, it’s nearly as long as the bird itself!
– It is the only bird with a bill longer than the rest of its body. This would be proportional to humans having a 13-foot long nose!
– Its tongue reaches 6 to 8 cm in length, also disproportionately long.
– Males of this species perform elaborate courtship displays, flying in loops up to 100 meters in the air.
– The wings of the sword-billed hummingbird beat up to 90 times per second – one of the fastest of any hummingbird.
– It’s estimated that the sword-billed hummingbird visits between 1,000 to 2,000 flowers per day to fuel its high metabolism.
In summary, the sword-billed hummingbird is an incredible and unique species with many fascinating adaptations to its extreme feeding niche. This charismatic high-altitude hummingbird remains a mysterious and captivating subject of study for ornithologists around the world. With ongoing conservation efforts, hopefully future generations can continue to appreciate its splendor in the wild.