The calliope hummingbird ( ; ''Selasphorus calliope'') is the smallest

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

native to the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. It has a western breeding range mainly from

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

, and migrates to the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, and

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

for its wintering grounds. The calliope hummingbird is the smallest known long-distance bird migrant, completing migrations twice per year of some . It was previously considered the only member of the genus ''Stellula'' (meaning ''little star''), but research evidence suggests its existing placement in the genus '' Selasphorus''. The bird was named after the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

muse In ancient Greek religion and Greek mythology, mythology, the Muses (, ) were the Artistic inspiration, inspirational goddesses of literature, science, and the arts. They were considered the source of the knowledge embodied in the poetry, lyric p ...

Calliope In Greek mythology, Calliope ( ; ) is the Muse who presides over eloquence and epic poetry; so called from the ecstatic harmony of her voice. Hesiod and Ovid called her the "Chief of all Muses". Mythology Calliope had two famous sons, OrpheusH ...

Description

The calliope is the smallest breeding bird found in

and the

. An adult calliope hummingbird can measure in length, span across the wings and weigh . Calliope hummingbirds have glossy green on the back and crown with white underparts. The adult male has wine-red streaks on the

gorget A gorget ( ; ) was a band of linen wrapped around a woman's neck and head in the English medieval clothing, medieval period or the lower part of a simple chaperon (headgear), chaperon hood. The term later described a steel or leather Collar (c ...

, green flanks, and a dark tail. When an adult male is competing for territory or females, the dark red feathers of its gorget distend outwards to create a more distinct appearance. Females and immatures have a pinkish wash on the flanks, dark streaks on the throat and a dark tail with white tips. The only similar birds are the rufous hummingbird and the Allen's hummingbird, but these birds are larger with more distinct and contrasting rufous markings on the tail and flanks, and longer central tail feathers. Calliope-nest edit

Habitat and distribution

The breeding habitat of calliope hummingbird is varied among open shrub habitats and altitudes. Nesting usually occurs at higher altitudes in the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

. Nests have been observed from as low as in

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

and Washington elevation to the

tree line The tree line is the edge of a habitat at which trees are capable of growing and beyond which they are not. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually low ...

at over . In

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, the minimum elevation observed for breeding is . Open

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

forest, mountain meadows, and

willow Willows, also called sallows and osiers, of the genus ''Salix'', comprise around 350 species (plus numerous hybrids) of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known ...

and

alder Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ex ...

thicket A thicket is a very dense stand of trees or tall shrubs, often dominated by only one or a few species, to the exclusion of all others. They may be formed by species that shed large numbers of highly viable seeds that are able to germinate in th ...

s may variously serve as breeding grounds. During migration and winter, they also occur in

chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...

lowland Upland and lowland are conditional descriptions of a plain based on elevation above sea level. In studies of the ecology of freshwater rivers, habitats are classified as upland or lowland. Definitions Upland and lowland are portions of a ...

brushy areas,

deserts A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the l ...

and semi-desert regions. They nest in western

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

from southern

and

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

south to

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

and southern

. During winter, they move mainly through

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

and

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

and northern

, to winter in southwestern

Behavior

Calliope hummingbirds are a migratory bird, generally leaving their breeding grounds earlier than most birds (although not as early as the rufous hummingbird) to take advantage of the late-summer wildflowers in the mountains of western North America. They are believed to be the smallest-bodied long distance migrant in the world. These birds feed on nectar from flowers using a long extendable tongue, drink sap from holes created by sapsuckers or catch

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s on the wing. While collecting

nectar Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...

, they also assist in plant

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

. Plants preferred for pollinating include

paintbrush A paintbrush is a brush used to apply paint or ink. A paintbrush is usually made by clamping bristles to a handle with a ferrule. They are available in various sizes, shapes, and materials. Thicker ones are used for filling in, and thinner ones ...

penstemon ''Penstemon'' , the beardtongues, is a large genus of roughly 280 species of flowering plants native to North America from northern Canada to Central America. It is the largest genus of flowering plants endemic to North America. As well as bein ...

, columbine, trumpet gilia, and elephant head. They will also occasionally catch and eat small

s and

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

s. Adult males usually arrive on the breeding ground before females, from mid-April to early May. The male claims and vigorously defends a nesting territory in which he will breed with many females. The male takes no part in raising the young and often actually vacates the breeding grounds by the time the young hatch. The female usually builds an open cup nest in a

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

tree under an overhanging branch, though apple and

trees have also been used. The nest is often built on the base of large pine cones and somewhat resembles a pine cone itself. A nest may be used repeatedly over the course of several years. Two eggs are laid from late May to early July and are incubated for 15 to 16 days. The young are capable of flight about 20 days after hatching.

Humming

The prominent humming sound of a calliope hummingbird as for all hummingbirds during flight and hovering derives from its rapid wingbeats while feeding or interacting with other hummingbirds. Humming serves as an audible communication to alert other birds of the arrival of a fellow forager or potential mate. The humming sound derives from

aerodynamic force In fluid mechanics, an aerodynamic force is a force exerted on a body by the air (or other gas) in which the body is immersed, and is due to the relative motion between the body and the gas. Force There are two causes of aerodynamic force: * ...

s generated by both the downstrokes and upstrokes of the rapid wingbeats, producing acoustic oscillations and harmonics.

Courtship display and sonation

During

courtship Courtship is the period wherein some couples get to know each other prior to a possible marriage or committed romantic, ''de facto'' relationship. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marri ...

, a male calliope hummingbird hovers at accelerated wingbeat

frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

up to 95 flaps per second (42% higher than normal hovering), creating a loud buzzing sound, with throat feathers protruding and facing a female. The male then ascends temporarily to and dives at high speed, with the rapid descent causing

sonation Sonation is the sound produced by birds, using mechanisms other than the Syrinx (biology), syrinx. The term ''sonate'' is described as the deliberate production of sounds, not from the throat, but rather from structures such as the bill, wings, ta ...

of wing and tail feathers combined with vocalization, intending to attract attention of the female. Research in a

wind tunnel A wind tunnel is "an apparatus for producing a controlled stream of air for conducting aerodynamic experiments". The experiment is conducted in the test section of the wind tunnel and a complete tunnel configuration includes air ducting to and f ...

demonstrated that the male courtship display includes sounds produced by three independent feather or vocal components, each with different acoustic characteristics, thus potentially containing different messages appealing to the female. The tail feathers flutter at high frequency and hit each other to produce the buzzing sound. Male calliope hummingbirds also make visual displays to females and nearby males by extending their purple gorget feathers to appear larger.

Temperature regulation

The high metabolic rate of calliope hummingbirds – especially during rapid forward flight and hovering – produces increased body heat that requires specialized mechanisms of

temperature regulation Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...

for dissipating heat, which becomes an even greater challenge in hot, humid climates. As the smallest North American hummingbird species, calliopes appear to adapt their relatively higher surface-to-volume ratio to improve convective cooling from air movement by the wings. When air temperatures rise above , thermal gradients driving heat passively by convective dissipation from around the eyes, shoulders, and feet are reduced or eliminated, requiring heat dissipation mainly by evaporation and

exhalation Exhalation (or expiration) is the flow of the breathing, breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing. This happens due to elastic properties of ...

. All hummingbirds dissipate heat partially by exhaled air, and from body structures with thin or no feather covering, such as around the eyes, shoulders, under the wings (

patagia The patagium (: patagia) is a membranous body part that assists an animal in obtaining lift when gliding or flying. The structure is found in extant and extinct groups of flying and gliding animals including bats, theropod dinosaurs (includin ...

), and feet. While hovering, calliope hummingbirds do not benefit from the heat loss by air convection during forward flight, except for air movement generated by their rapid wing-beat, possibly aiding convective heat loss from the extended feet.

Status

As of 2019, calliope hummingbirds have a relatively stable breeding population of about 4.5 million. As this species has a restricted wintering range in

and travels an exceptional migratory distance annually of up to 9,000 km, it is on a watchlist for factors that could diminish the population.

Threats

The calliope hummingbird does not have many predators. Its biggest threat is likely long cold spells since they reduce the volume of insects and nectar available in its environment. The calliope hummingbird may be aggressive in its territory with other hummingbird species and birds, including Gray Flycatchers, American Robins, and Red-tailed Hawks.

References

{{Taxonbar, from=Q27074788 calliope hummingbird Native birds of Western Canada Native birds of the Northwestern United States Native birds of the Western United States Birds of the Sierra Nevada (United States) Meso-American wintering birds calliope hummingbird calliope hummingbird