Thesword-billed hummingbird (Ensifera ensifera), also known as theswordbill, is aneotropical species ofhummingbird from theAndean regions ofSouth America. It is theonly member in thegenusEnsifera. Among the largest species of hummingbird, it is characterized by its unusually longbill, being the only bird to have a beak longer than the rest of its body, excluding the tail. It uses its bill to drinknectar from flowers with longcorollas and hascoevolved with the speciesPassiflora mixta. While most hummingbirdspreen using their bills, the sword-billed hummingbird uses its feet to scratch and preen due to its bill being so long.

Sword-billed hummingbird
Male
Female sword-billed hummingbird (right) with abuff-tailed coronet
Conservation status
Least Concern (IUCN 3.1)[1]
CITES Appendix II (CITES)[2]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Clade:	Strisores
Order:	Apodiformes
Family:	Trochilidae
Tribe:	Heliantheini
Genus:	Ensifera Lesson, 1843
Species:	E. ensifera
Binomial name
Ensifera ensifera (Boissonneau, 1840)
Distribution range of the sword-billed hummingbird
Synonyms
Ornismya ensiferaBoissonneau, 1840

The sword-billed hummingbird is atrap-line feeder and feeds onnectar, especially fromPassiflora mixta and otherpassionflowers. It alsohawks for insects. It breeds from February to March and buildscup nests using moss. The sword-billed hummingbird is listed as being ofleast concern by theInternational Union for Conservation of Nature (IUCN) on theIUCN Red List, but is threatened byclimate change anddeforestation.

The sword-billed hummingbird was firstdescribed asOrnismya ensifera byAuguste Boissonneau in 1839 on the basis of specimens fromSanta Fé,Bogotá, Colombia.^[3] It was moved to the genusEnsifera in 1843 byRené Lesson.^[4] The generic and specific nameensifera is derived from theLatin wordsensis (sword) andferre (to carry) and means sword-wielder, referring to the species' large beak.^[5] Sword-billed hummingbird is the officialcommon name designated by theInternational Ornithologists' Union.^[6] Other common names for the species include sword billed hummingbird, swordbill, and swordbill hummingbird.^[7][8]

The sword-billed hummingbird is theonly species in thegenusEnsifera. In 1939,Ensifera ensifera caerulescens was described as a subspecies by Willoughby Lowe on the basis of a specimen from theRoyal Albert Memorial Museum.^[9] However, it has since beenlumped with thenominate subspecies as it is likely that the specimen had either aberrantplumage or was discolored. The species is now consideredmonotypic.^[10]

The sword-billed hummingbird is among the largest species of hummingbirds. Adults are 13–14 centimetres (5.1–5.5 in) long excluding thebill and weigh 10–15 g (0.35–0.53 oz), with males being slightly larger on average than females.^[11] The most distinctive feature of the species is the enormous bill, which is 8–12 centimetres (3.1–4.7 in) long.^[12] The bill is the largest of any hummingbird and the largest with respect to body length for any bird.^[10]

The sword-billed hummingbird displayssexual dimorphism. Males have shorter bills but longer wings and tails than females. Males have bronze-greenupperparts with coppery-bronze heads, a discreet white spot behind the eye, dusky throats, metallic greenunderparts, a dark gray belly, and a forked blackish bronze-green tail. Some males have white on the chin and throat. Females have similar upperparts, but have white underparts and grayish throats and bellies speckled with green. The tail is less deeply forked and is edged grayish white. Juveniles look similar to females.^[10][11]

The sword-billed hummingbird is the only known bird whose bill is longer than the rest of the body, excluding the tail.^[11][13] It is black, heavy, and slightly upturned.^[11] The extremely long bill helps the species feed on flowers with longcorollas that are inaccessible to other species.^[12]

The sword-billed hummingbird makes a low,guttural, slightly trilledtrrr.^[10][11]

The sword-billed hummingbird is found in theAndes from westernVenezuela throughColombia,Ecuador, andPeru toBolivia.^[14] It inhabits humid and wetmontane forest,forest edges,shrubland, gardens, and patches ofpáramo at elevations of 1,700–3,500 m (5,600–11,500 ft), but is most common at elevations of 2,400–3,100 m (7,900–10,200 ft). The species is generallynon-migratory, but shows localized movements in Colombia and northwestern Venezuela, where it moves to higher altitudes in the earlywet season and returns to lower elevations in thedry season.^[10][11]

The sword-billed hummingbird's distribution correlates with the distribution of species of thesubgenusTacsonia in the genusPassiflora, due to its highly specialized bill and feeding habits.^[12][15]

As is characteristic of hummingbirds, the sword-billed hummingbird can fly backwards andhover in the air.^[16] It also exhibits higher than averagewing-disk loading than other members of its family.^[17]

The sword-billed hummingbird is aspecialist feeder, feeding mainly on the nectar of flowers with long corollas, includingBrugsmania sanguinea,Datura stramonium,Passiflora mixta,P. pinnatistiplua,P. mollissima andP. sexflora, along with flowers from the generaAethanthus,Fuchsia,Salpichroa, andSolanum. It probes flowers from below while feeding, and is atrap-line feeder, visiting a specific series of flowers in a regular, consistent sequence. It alsohawks for insects, catching flying insects by keeping the bill open.^[10]

The sword-billed hummingbird perches with its bill angled upwards to reduce the strain of the heavy beak and improve balance.^[10] The length of the bill is so long, it also forces the sword-billed hummingbird to use its feet to groom, even though this takes longer than traditional beak methods.Preening is important to removeectoparasites and spread oil across the feathers.^[18]

Breeding occurs from February to March. Nests arecup-shaped and made of moss, and are usually hung among root fibers high above the ground.^[11]

The sword-billed hummingbird displays extremecoevolution with thepassionflowerPassiflora mixta. The two species evolved together during the early radiation of the subgenusTacsonia, because the species exclusively pollinatedP. mixta. The position of the flower'santhers andstigmas, along with the length of thecorolla tube, make it an inaccessible food source to nearly every species except the sword-billed hummingbird. Thismutualistic relationship letsP. mixta depend on the bird for pollination, while the bird obtains a high-quality food source.^[19] To obtain nectar, the hummingbird will stick its long bill down the tube of the corolla (both of which are almost exactly the same length), drink, and then retreat and hover for a few seconds before repeating the process. Other species, such as insects, may be able to access the flower's nectar but do so by puncturing the base and feeding through a hole instead of the corolla tube. Additional evidence of coevolution is that both species also inhabit the same territory range along the Andean mountains. If sword-billed hummingbird populations were to decline, there would most likely be a negative impact on the abundance ofP. mixta flowers due to their extreme coevolution.^[15]

The sword-billed hummingbird is listed as being ofleast concern by theInternational Union for Conservation of Nature (IUCN) on theIUCN Red List due to its large range, lack of significant population decline, and lack of major threats. There is also no census on global number of individuals, because of the large range of occurrence and uncommon sightings.^[14] It has adapted to man-made habitats in some areas and is also known to occur in several protected areas.^[10]Climate change anddeforestation are the two most probable threats to the sword-billed hummingbird as they may lead to habitat loss and a decrease in food sources, especially ofPassiflora mixta.^[19]

TheBBC's documentary seriesPlanet Earth II depicted the sword-billed hummingbird flying through the forest in the episode "Jungles".^[13]

• Explore Species: Sword-billed Hummingbird at eBird (Cornell Lab of Ornithology)

• Skeletal structure photo and description