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The elf owl (''Micrathene whitneyi'') is a small grayish-brown owl about the size of a sparrow found in the
Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, ...
, central
Mexico Mexico ( Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Gua ...
, and the Baja California peninsula. It has pale yellow eyes highlighted by thin white "eyebrows" and a gray bill with a horn-colored tip. The elf owl frequently inhabits woodpecker holes in saguaro cacti; it also nests in natural tree cavities. It is nocturnal and feeds primarily on insects.


Taxonomy

The elf owl was formally described in 1861 by the American naturalist James Graham Cooper from a specimen collected near Fort Mohave in
Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fo ...
. He coined the
binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...
''Athene whitneyi'', choosing the specific epithet to honour the geologist Josiah Whitney. The owl is now the only species placed in the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial no ...
''Micrathene'' that was introduced in 1866 specifically for the elf owl by American ornithologist
Elliott Coues Elliott Ladd Coues (; September 9, 1842 – December 25, 1899) was an American army surgeon, historian, ornithologist, and author. He led surveys of the Arizona Territory, and later as secretary of the United States Geological and Geographi ...
. The genus name combines the Ancient Greek ''mikros'' meaning "small" and the genus name '' Athene'' that had been introduced by
Friedrich Boie Friedrich Boie (4 June 1789 – 3 March 1870) was a German entomologist, herpetologist, ornithologist, and lawyer.Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins Universi ...
in 1822. A
molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
study of the owls published in 2019 found that the elf owl is a sister species to the South American long-whiskered owlet (''Xenoglaux loweryi'') that was first described in 1977. Four
subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
are recognized: * ''M. w. whitneyi'' ( Cooper, JG, 1861) – southwest USA and northwest Mexico * ''M. w. idonea'' ( Ridgway, 1914) – south Texas (USA) to central Mexico * ''M. w. sanfordi'' (Ridgway, 1914) – south
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Me ...
(Mexico) *† ''M. w. graysoni'' Ridgway, 1886 –
Socorro Island Socorro Island ( es, Isla Socorro) is a small volcanic island in the Revillagigedo Islands, a Mexican possession lying off the country's western coast. The size is 16.5 by 11.5 km (10.25 by 7.15 miles), with an area of . It is the larges ...
(off west Mexico) (extinct) ''M. w. idonea'', the subspecies in southernmost Texas to central Mexico, is resident, as are the isolated ''M. w. sanfordi'' of southernmost
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Me ...
and ''M. w. graysoni'' (Socorro elf owl) of
Socorro Island Socorro Island ( es, Isla Socorro) is a small volcanic island in the Revillagigedo Islands, a Mexican possession lying off the country's western coast. The size is 16.5 by 11.5 km (10.25 by 7.15 miles), with an area of . It is the larges ...
, southwest from the tip of Baja California. The Socorro elf owl has not been recorded since 1931 and is assumed to be extinct.


Description

The elf owl is the world's lightest owl, although the long-whiskered owlet and the Tamaulipas pygmy owl are of a similarly diminutive length. It is also the world's smallest owl. The mean body weight of this species is . These tiny owls are long and have a wingspan of about . Their primary projection (flight feather) extends nearly past their tail. They have fairly long legs and often appear bow-legged. They are often found in
chaparral Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterrane ...
, and are easily found during their breeding season. During dusk and just before dawn are the times this owl is most active, when they can often be heard calling to one another in a high-pitched whinny or chuckle. These songs often consist of 5–7 notes that repeat in short duration, similar to the sound of a young puppy. The distinctive vocalizations of elf owls vary according to sex, with males exhibiting a wider repertoire of complex notes as opposed to females of the same species. Males have two primary classifications of songs, each of which share similar characteristics of structure and function. Most avian observers refer to "Class A" songs to describe those that vary in length (generally 5–15 notes), and are used as both territorial proclamation and to herald the arrival of males to females in the area. While Class A tones reflect changes in environmental factors — wind, precipitation, moonlight, and temperature — Class B songs have significantly less variation among individuals. Class B functions as the primary mating call, stimulating females and encouraging them to accept male sexual advances. As the season goes on and mating begins, Class A songs are observed with lower frequency than Class B. There are also a handful of locational, so-called "scolding", and territorial songs belonging to both male and female birds of the elf owl species.


Distribution and habitat

The elf owl is known to migrate in large groups, with patterns of migration varying depending on flock and habitat location. Some broods of elf owl migrate to the southwest United States (California, Arizona, New Mexico, and Texas) in the spring and summer for breeding. In the winter, it is found in central and southern Mexico. Migrant elf owls return north in mid-April to early May. Resident populations occur in a couple of places in south central Mexico and along the Baja peninsula.


Behaviour and ecology

Elf owls feign death when handled, an adaption that encourages a predator to relax its grip so that the owl can escape. Elf owls are also notoriously territorial. Territories are established by the male and are defended by both the male and the female, and males also tend to view their chosen female mate as a territory to be defended, as well. This defense is often accomplished through the use of song. During the breeding season, elf owls are monogamous and stay in breeding pairs, but can be found in small groups during migration and when mobbing predators. Adults as well as young can be subject to predation by other predatory
birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight ...
such as jays,
hawks Hawks are birds of prey of the family Accipitridae. They are widely distributed and are found on all continents except Antarctica. * The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks and others. This subfamily ...
, and
owls Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers ...
.


Breeding

Elf owls usually choose abandoned, north-facing
woodpecker Woodpeckers are part of the bird family Picidae, which also includes the piculets, wrynecks, and sapsuckers. Members of this family are found worldwide, except for Australia, New Guinea, New Zealand, Madagascar, and the extreme polar regions ...
cavities in saguaro cacti, sycamores, cottonwoods, and other hardwood trees, to raise their young. While some cavity nesters utilize vegetation as nesting substrate, elf owls have been observed removing this vegetation and prefer a bare cavity. While elf owls primarily use natural structures for their nesting, they have been known to nest in man-made structures such as telephone poles in urban areas. As populations decrease due to encroachment by urbanization, this may serve elf owls well (for more, see ''Conservation status''). They generally mate for periods of three months, with male and female birds remaining in close proximity. During this time, females engage in the singing of locational calls (see ''Description'' for more information on elf owl vocalizations), and males respond with mating rituals of their own. Males and female forage independently during this time, but the male elf owl will often hunt for the female as she remains in the pairs' chosen habitat for the mating season. While three eggs is a very common clutch size, females may lay anywhere from one to five eggs in springtime (late March to early May). The eggs are usually round or oval shaped with a white coloration and are from 26.8 x 23.2 to 29.9 x 25.0 mm in size. The eggs are incubated for about 24 days before the chicks hatch. The young owlets fledge at about 10 weeks. Usually, chicks are born in mid-June or early July. By the end of July, they are almost always fledged and ready to set out on their own. After the young hatch, the female elf owl watches over them in the nesting cavity while the male often hunts for the young and the female herself. The male elf owl does most of the caretaking himself, feeding his brood independent of the female, who resides in the cavity. Generally this period of communal rearing lasts until the brood is 17 to 21 days of age. Elf owls live 3 to 6 years; in captivity they may live up to 10 years. The most common types of mortality for these owls are predation, exposure, and inter-species as well as intra-species competition.


Food and feeding

Hunting is performed mostly during nocturnal hours. Straight line flight is often deployed for this purpose but they will use an arced flight when in the vicinity of the nest and for flying to and from perches. They live in cacti much like some birds, using the shade and climate the cacti provide. Elf owls feed mainly on arthropods such as moths, crickets, scorpions, centipedes, and beetles. Agaves and ocotillos are ideal places for foraging, as moths and other insects may be found in their flowers. In urban areas they can be seen utilizing outdoor lights that attract bugs as areas for insect hunting. They are often seen chasing after flying insects, with a flight similar to a
tyrant flycatcher The tyrant flycatchers (Tyrannidae) are a family of passerine birds which occur throughout North and South America. They are considered the largest family of birds known to exist in the world, with more than 400 species. They are the most di ...
's. They also feed on scorpions. Once the owl has killed the scorpion, they can be observed removing the stinger before consumption. The elf owls seem to not be bothered by scorpion stings. They will also feed on small
mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), f ...
(such as kangaroo rats),
reptiles Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocepha ...
(
spiny lizard Spiny lizards is a common name for the genus ''Sceloporus'' in the family Phrynosomatidae. The genus is endemic to North America, with various species ranging from New York, to Washington, and one occurring as far south as northern Panama. Kö ...
s, earless lizards and blind snakes) and
birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight ...
, on occasion.https://animaldiversity.org/accounts/Micrathene_whitneyi/


Conservation status

Populations of elf owls have continued to decline in recent years due to a continued loss of native habitats, particularly those in the desert areas of California. Human activities, like increasing
water diversion Interbasin transfer or transbasin diversion are (often hyphenated) terms used to describe man-made conveyance schemes which move water from one river basin where it is available, to another basin where water is less available or could be utilized ...
and home construction, have decimated these desert and riparian areas, as well as increasingly abundant invasive species (such as the salt cedar). The destruction of habitat leaves many elf owls unable to nest, hunt, and reproduce in areas like California, Arizona, and elsewhere. To date, elf owls are not considered a globally threatened species, yet they are listed as "endangered" in California due to a population of fewer than 150,000 individual owls in the United States. California has implemented a captive breeding program in an attempt to increase this number, while numerous environmental and government agencies work to preserve their riparian and desert homes. Some sources report that the elf owl has already been nearly eliminated in California.


In fiction

An elf owl named Gylfie is a major character in the '' Guardians of Ga'Hoole'' book series by Kathryn Lasky, and the 2010 film adaptation. An elf owl plays a major role in the technothriller ''The Elf Owl and Imagined Amenities'', by Sam Biondo.


References


General references

* Biondo, Sam (2013). ''The Elf Owl and Imagined Amenities'' (Kindle ed.). . * del Hoyo, Josep (ed.) (2014). ''Handbook of the Birds of the World Vol. 5: Barn-owls to Hummingbirds''. Barcelona: Lynx Ed. . * National Geographic (2002). ''Field Guide to the Birds of North America'', 4th ed. . * Sibley, David Allen (2014). ''The Sibley Guide to Birds'', 2nd ed. New York: Knopf. .


External links


Elf Owl photo galleryCornell Lab of Ornithology entry for the Elf owl.
Includes photograph and audio recording.
Elf owl fact sheet
from the Arizona-Sonora Desert Museum. {{Taxonbar, from=Q926291 elf owl Native birds of the Southwestern United States Birds of the Rio Grande valleys Birds of Mexico elf owl Natural history of the Revillagigedo Islands elf owl elf owl Birds of the Sierra Madre Occidental Birds of the Trans-Mexican Volcanic Belt Fauna of the Sonoran Desert