The green thorntail (''Discosura conversii'') is a small

hummingbird Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With about 361 species and 113 genera, they occur from Alaska to Tierra del Fuego, but the vast majority of the species are found in the tropics ar ...

in the "coquettes", tribe

Lesbiini Lesbiini is one of the two tribes that make up the subfamily Lesbiinae in the hummingbird family Trochilidae. The other tribe is Heliantheini (brilliants). The informal name "coquettes" has been proposed for this group as the largest genus, ...

of subfamily

Lesbiinae Lesbiinae is one of the six subfamilies that make up the hummingbird family Trochilidae. The subfamily is divided into two tribes: Heliantheini ("brilliants") containing 14 genera and Lesbiini ("coquettes") containing 18 genera. Phylogeny A mol ...

. It is found in Colombia, Costa Rica,

Ecuador Ecuador ( ; ; Quechuan languages, Quechua: ''Ikwayur''; Shuar language, Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechuan ...

, and

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...

.HBW and BirdLife International (2020) ''Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world'' Version 5. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v5_Dec20.zip xls zipped 1 MBretrieved May 27, 2021

Taxonomy and systematics

The green thorntail and three other species were at one time placed in genus ''Popelairia'' but since the late 1900s that genus has been merged into the present ''Discosura''. Some authors have further merged ''Discosura'' into ''Lophornis'' but this treatment has not been widely accepted. Though early authors proposed two subspecies for the green thorntail, current taxonomies treat it as

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

.Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, J. A. Gerbracht, D. Lepage, B. L. Sullivan, and C. L. Wood. 2021. The eBird/Clements checklist of Birds of the World: v2021. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/ Retrieved August 25, 2021Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 24 August 2021. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved August 24, 2021Schulenberg, T. S. (2020). Green Thorntail (''Discosura conversii''), version 1.0. In Birds of the World (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.gretho1.01 retrieved January 23, 2022

Description

Male green thorntails are about long and females about . Five individuals whose sex was not recorded had an average weight of . The adult male has a dark green crown and a lighter more metallic green back. The coppery bronze rump has bluish black inclusions and a white band across it. The bluish black tail is deeply forked and the outer feathers are very narrow, giving the species its common name. The throat is bright metallic green and the breast and belly mostly darker green with the center of the breast being metallic greenish blue. The adult female's upperparts are like the male's but for a darker rump. Its tail is notched but not elongated. All but the outermost pair of tail feathers are bluish black with dark green bases; the outmost have white bases, a blue-black middle, and white tips. Their face has a broad white cheek patch. The chin is dull black with white spots, the flanks dull green with a white spot, and the breast and belly dull black. Juveniles are like the adults but with a grayish white chin.

Distribution and habitat

The green thorntail is found on the Caribbean slope in Costa Rica and the Pacific slopes of Panama, Colombia, and Ecuador almost to the Peruvian border. It is thought to also occur on the Caribbean side of eastern Panama. It is primarily a

forest canopy In biology, the canopy is the aboveground portion of a plant cropping or crop, formed by the collection of individual plant crowns. In forest ecology, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns an ...

species, inhabiting the upper levels of the interior and edges of humid

montane forest Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucia ...

and lowland

evergreen forest An evergreen forest is a forest made up of evergreen trees. They occur across a wide range of climatic zones, and include trees such as conifers and holly in cold climates, eucalyptus, Live oak, acacias, magnolia, and banksia in more temperat ...

. It also occurs at flowering trees in clearings. In elevation it mostly ranges from in Costa Rica, in Panama, from near sea level to in Colombia, and at in Ecuador.

Behavior

Movement

The green thorntail is generally resident throughout its range but it also tends to move to its lower elevations during the wet season.

Feeding

The green thorntail forages for nectar mostly at the tops of flowering trees but also from epiphytes and shrubs. It appears to favor

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock fo ...

s. It nectars while hovering with its tail cocked at nearly a right angle to its body. Its diet also includes small

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

s such as

flies Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwing ...

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. Th ...

s, and

spider Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species d ...

s that it captures by hawking from a perch and gleans from the underside of leaves while hovering.

Breeding

Breeding male green thorntails perch on high bare twigs and sometimes give a dive display. The species' breeding season appears to vary across its range but are not well defined. It is thought to span from November to April in Costa Rica, and displays have been noted in Colombia in June. All hummingbirds lay two white

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

s that are incubated by the female alone, but no details of the species' breeding

phenology Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation). Examples include the date of emergence of leav ...

are known and the nest has not been described.

Vocalization

The green thorntail is usually silent, but makes "soft, squeaky chipping in interactions".

Status

The IUCN has assessed the green thorntail as being of Least Concern though its population size is not known and is believed to be decreasing. It is judged to be rare and local in Panama, uncommon to common in Colombia, and uncommon in Costa Rica and Ecuador. It is "vulnerable to widespread habitat loss or degradation, but otherwise human activity probably has little short term effect on this species." Green thorntail (Discosura conversii) male in flight.jpg, Male, Mount Totumas cloud forest,

Green Thorntail 1.jpg, Male