![]() | Parts of this article (those related to screech owl evolution, taxonomy, and systematics) need to be updated.(September 2019) |
Screech owl Temporal range: Miocene to present | |
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Eastern screech owl, Megascops asio Rufous morph | |
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Gray morph | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Strigiformes |
Family: | Strigidae |
Genus: | Megascops Kaup, 1848 |
Type species | |
Strix acio Linnaeus, 1758 | |
Species | |
Some 22, see text | |
Synonyms | |
MacabraCarlo Bonaparte, 1854 |
Screech owls are typical owls (Strigidae) belonging to the genus Megascops with 22 living species. For most of the 20th century, this genus was merged with the Old World scops owls in Otus, but nowadays it is again considered separately based on a range of behavioral, biogeographical, morphological, and DNA sequence data.
Screech owls are restricted to the Americas. Some species formerly placed with them are now considered more distinct (see below for details).
Similar to other owls, the screech owl females are larger than the males of their species. They have a compact size and shape. They are small and agile, and about 7 to 10 inches tall and have a wingspan around 18 to 24 inches. They have prominent, wide-set feather tufts with bright yellow/green eyes. They have different brownish hues with whitish, patterned underside. This coloration helps them get camouflage against the tree bark.
Screech owls hunt from perches in semiopen landscapes. They prefer areas that contain old trees with hollows; these are home to their prey, which includes insects, reptiles, small mammals such as bats and mice, and small birds. Screech owls have a good sense of hearing, which helps them locate their prey in any habitat. They also possess well-developed raptorial claws and a curved bill, both of which are used for tearing their prey into pieces small enough to swallow easily. They usually carry their prey back to their nests, presumably to guard against the chance of losing their meal to a larger raptor.
Screech owls are primarily solitary. During the late winter breeding season, however, males make nests in cavities, sometimes reusing abandoned nests of other animals, to try to attract females. The females select their mate based on the quality of the cavity and the food located inside. During the incubation period, the male feeds the female. These birds are monogamous, with biparental care. The young of most screech owls are altricial to semialtricial. [1]
Northern screech owls are found in eastern states, such as New Jersey and New York. The screech owls are named for their piercing calls. Their normal territorial call is not a hoot as with some owls, but a trill consisting of more than four individual calls per second given in rapid succession (although the sound does not resemble screeching or screaming). They also have a kind of "song" used in courtship, and as a duet, between members of a pair. Calls differ widely between species in type and pitch, and in the field are often the first indication of these birds' presence, as well as the most reliable means to distinguish between species. The distinctness of many species of screech owls was first realized when vastly differing calls of externally similar birds from adjacent regions were noted.
The genus Megascops was introduced by German naturalist Johann Jakob Kaup in 1848. [2] The type species is the eastern screech owl (Megascops asio). [3] The evolutionary relationships of the scops and screech owls are not entirely clear. What is certain is that they are very closely related; they may be considered sister lineages which fill essentially the same ecological niche in their allopatric ranges. A screech owl fossil from the Late Pliocene of Kansas [4] (which is almost identical to eastern and western screech owls) indicates a longstanding presence of these birds in the Americas, while coeval scops owl fossils very similar to the Eurasian scops owl have been found at S'Onix on Majorca. [5] The scops and screech owl lineage probably evolved at some time during the Miocene (like most other genera of typical owls), and the three (see below) modern lineages separated perhaps roughly 5 million years ago. Note, no reliable estimate of divergence time is known, as Otus and Megascops are osteologically very similar, as is to be expected from a group that has apparently conserved its ecomorphology since before its evolutionary radiation. Like almost all scops and screech owls today, their common ancestor was in all probability already a small owl, with ear tufts and at least the upper tarsus ("leg") feathered.
However that may be, the hypothesis that the group evolved from Old World stock [6] is tentatively supported by cytochrome b sequence data. [7] [8] The screech owls also have a different placement of the procoracoid (less of an anterior incline) and coracoid bones compared to other New World owls. [9]
While late-19th-century ornithologists knew little of the variation of these birds, which often live in far-off places, with every new taxon described a few differences between the Old and New World "scops" owls became more and more prominent. Namely, the scops owls give a whistling call or a row of high-pitched hoots with fewer than four individual hoots per second. This call is given in social interaction or when the owl tries to scare away other animals. The screech owls, though, are named for their piercing trills of more than four individual notes per second, and as noted above, they also have a kind of song, which is absent in the scops owls. A few other differences are seen, such as brown coloration below being common in scops owls and almost never seen in screech owls, but the difference in vocalizations is most striking.
By the mid-19th century, Otus was becoming identified as encompassing more than one genus. First, in 1848, the screech owls were split off as Megascops. Subsequently, the highly apomorphic white-throated screech owl of the Andes was placed in the monotypic genus Macabra in 1854. Gymnasio was established in the same year for the Puerto Rican owl, and the bare-legged owl (or "Cuban screech owl") was separated in Gymnoglaux the following year; the latter genus was sometimes merged with Gymnasio by later authors.
By the early 20th century, the lumping together of taxa had come to be preferred. The third edition of the American Ornithologists' Union (AOU) checklist in 1910, placed the screech owls back in Otus. Although this move was never unequivocally accepted, it was the dominant throughout most of the 20th century. In 1988, attempts to resolve this were made by re-establishing all those genera split some 140 years earlier at subgenus rank inside Otus. [10] Still, the diversity and distinctness of the group failed to come together in a good evolutionary and phylogenetic picture, and until the availability of DNA sequence data, this could not be resolved. In the mid- to late 1990s, preliminary studies of mtDNA cytochrome b across a wide range of owls found that even the treatment as subgenera was probably unsustainable and suggested that most of the genera proposed around 1850 should be accepted. [7] [8] Though some debate arose about the reliability of these findings at first, [11] they have been confirmed by subsequent studies. In 2003, the AOU formally accepted the genus Megascops again. [12]
The bare-legged owl was also confirmed as distinct enough to warrant separation in its own genus. Furthermore, the white-throated screech owl was recognized as part of an ancient lineage of Megascops – including also the whiskered screech owl and the tropical screech owl, which previously were considered to be of unclear relationships – and indeed its call structure is not too dissimilar from the latter. Its distinct coloration, approximated in the southern whiskered screech owl (Megascops trichopsis mesamericanus), is thus likely the result of strong genetic drift.
Additionally, a population of the tropical screech owl from northern Colombia has recently been proposed as the Santa Marta screech owl (Megascops gilesi) to the IOC. [13] [14]
The genus contains 22 species: [15]
The true owls or typical owls are one of the two generally accepted families of owls, the other being the barn owls (Tytonidae). This large family comprises 230 living or recently extinct species in 24 genera. The typical owls have a cosmopolitan distribution and are found on every continent except Antarctica.
The eastern screech owl or eastern screech-owl, is a small owl that is relatively common in Eastern North America, from Mexico to Canada. This species resides in most types of woodland habitats across its range, and is relatively adaptable to urban and developed areas compared to other owls. Although it often lives in close proximity to humans, the eastern screech owl frequently avoids detection due to its strictly nocturnal habits.
The western screech owl is a small owl native to North and Central America, closely related to the eastern screech owl. The scientific name commemorates the American naturalist Robert Kennicott.
The Eurasian scops owl, also known as the European scops owl or just scops owl, is a small owl in the typical owl family Strigidae. Its breeding range extends from southern Europe eastwards to southern Siberia and the western Himalayas. It is migratory, wintering in Africa south of the Sahara.
Scops owls are typical owls in family Strigidae belonging to the genus Otus and are restricted to the Old World. Otus is the largest genus of owls with 59 species. Scops owls are colored in various brownish hues, sometimes with a lighter underside and/or face, which helps to camouflage them against the bark of trees. Some are polymorphic, occurring in a greyish- and a reddish-brown morph. They are small and agile, with both sexes being compact in size and shape. Female scops owls are usually larger than males.
The flammulated owl is a small migratory North American owl in the family Strigidae. It is the only species placed in the genus Psiloscops.
The Japanese scops-owl is a small owl species in the family Strigidae, or true owl family. It is a member of the genus Otus, the scops owl genus. It is resident to Japan, China, Korea, and Russia.
The Puerto Rican owl or múcaro común, formerly known as the Puerto Rican screech owl, is a mid-sized "typical owl" in subfamily Striginae. It is endemic to the archipelago of Puerto Rico though it formerly also inhabited the Virgin Islands.
The whiskered screech owl is a small screech owl found in North and Central America.
The Andaman scops owl is a species of the Strigidae family and is native to the Andaman Islands of India. It is a largely brown owl with white speckles and yellow eyes. The owl was first described in 1873 by British Ornithologist Allan Octavian Hume. The Andaman Scops Owl has no sightings outside of the Andaman Islands, therefore research on this bird is limited. This owl is not threatened, though an increase in deforestation on the islands has led to the population size slowly declining. It is a nocturnal owl that feeds at night and has a nesting season from February to April.
The black-capped screech owl, or variable screech owl, is a species of owl in the family Strigidae. It is found in Argentina, Brazil, and Paraguay.
The Middle American screech owl, also known as the Guatemalan screech owl, is a species of owl in the family Strigidae. It is found from northern Mexico to western Panama.
Koepcke's screech owl is a species of owl in the family Strigidae. It is endemic to Peru.
The long-tufted screech owl is a species of "typical owl" in the subfamily Striginae. It is found in Argentina, Brazil, and Uruguay.
The tawny-bellied screech owl is a species of owl in the family Strigidae. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela.
The foothill screech owl is a species of owl in the family Strigidae. It is found in Bolivia, Brazil, Colombia, Ecuador, Guyana, Suriname, and Venezuela.
The Chocó screech owl is a species of owl in the family Strigidae. It is found from central Panama to western Ecuador.
The vermiculated screech owl, is a subspecies of Middle American screech owl, or possibly separate species of owl in the family Strigidae. It is found in Costa Rica, Nicaragua, and Panama.
The Santa Marta screech owl is a species of owl in the family Strigidae. It is found only in the Sierra Nevada de Santa Marta of Colombia.
The tawny owl was first described by Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae in 1758, under its current scientific name Strix aluco. The binomial derives from the Greek strix "owl" and Italian allocco "tawny owl". Some early descriptions upon review were found to have somehow conflated the very different barn owl by describing it with the same scientific name Strix aluco, which in turn engendered some confusion.