| African grass owl | |
|---|---|
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Strigiformes |
| Family: | Tytonidae |
| Genus: | Tyto |
| Species: | T. capensis |
| Binomial name | |
| Tyto capensis (Smith, 1834) | |
The African grass owl (Tyto capensis) is a species of owl in the barn owl family, Tytonidae.
The African grass owl resembles the barn owl and has a heart shaped whitish-cream facial disc, with a narrow yellowish-buff rim which is densely spotted dark. The eyes are brownish-black, and the bill is whitish to pale pink. The entire upperparts from the crown to the lower back and wing-coverts are a uniform sooty blackish-brown, with scattered small white spots and greyish flecks. The primary feathers and secondary feathers are pale brownish-grey with dark bars and yellow bases. The short tail has uniform brown central feathers fading to paler, almost white, outer feathers which show about four dark bars. The underparts vary in colour from whitish to buff marked with dark spots. The legs have whitish feathers which extend to the lower third of the tarsi. The lower leg and feet are slightly bristled and coloured pale yellowish-grey. The body length is 38–42 cm (15–17 in), the wing length 283–345 mm (11.1–13.6 in) and they weigh between 355 and 520 g (12.5 and 18.3 oz). [3] A high degree of sexual dimorphism is present, whereby the body mass and length is significantly larger in females than in males. This is a consequence of observable differences in hunting techniques and efficiency of brooding. [4]
They have a screeching call which is similar to that of the Barn Owl, but it is less strident. A high-pitched sibilant tremolo lasting one to two seconds is thought to be the song of the male. [3]
It is distributed in sub-Saharan Africa where there are two blocks of its main range, one in central southern Africa across southern Congo and northern Angola to the central coast of Mozambique and the other centred on South Africa from the Western Cape north to the southern extremities of Zimbabwe, Botswana and Mozambique. There are isolated populations in the Ethiopian Highlands, Kenya and Uganda and Cameroon. [1] [3]
The African grass owl is found in moist grassland and open savanna up to an elevation of 3,200 m (10,500 ft). In east Africa it may also be found in dry grassland and at higher altitudes in Aberdares and on Mount Kenya. [3] In southern Africa this species generally prefers marshes and vleis where there are patches of tall, rank grass and other vegetation but it may also be found in fynbos, renosterveld and acacia scrub close to water. [5] The specific habitat requirements of the African grass owl characterize it as a habitat specialist. [6]
The African grass owl is nocturnal and is rarely seen flying during the day. It roosts during the day on the ground in tall, rank grass where it creates domed platforms and tunnels by trampling down the surrounding grass. These tunnels can be several metres long and connect with other tunnels. The domed platform created at the end of a tunnel serves as either the nest or daytime roost site. Pairs of owls frequently roost together and occasionally small groups of owls may roost quite close to each other. It becomes active after sunset and hunts during the night, only if prey is scarce, will they fly during the early morning or late afternoon. [3] Studies done in the Eastern Cape reveal that, in comparison with the Barn owl (Tyto alba), the African grass owl hunts later in the morning and earlier in the evening.
The preferred prey of the African grass owl are rodents and other small mammals normally weighing less than 100 g (3.5 oz) and taken from the ground. It normally hunts in an erratic flight close to the ground, listening and watching for prey, but will also "sit and wait" hunt from a perch. [3] When the owl locates prey it dives to the ground and picks it up with its talons, feeding on the ground or taking the prey on a nearby perch. [5] In southern Africa recorded prey items include Duthie's golden mole Chlorotalpa duthiae , African marsh rat Dasymus incomtus, Cape mole-rat Georychus capensis, vlei rats Otomys spp, multimammate mice Mastomys spp, Southern African hedgehog Atelerix frontalis, elephant shrews, hares and bats. Non mammalian prey included frogs, African snipe Gallinago nigripennis and termites. [5] The African grass owl in Cameroon significantly hunts Soricomorpha with 70% as its main diet, while the African grass owl in different regions hunts rodentia with 90% in average. [7]
The African grass owl breeds from December to August, but the main breeding season is from February to April. The nest is a shallow hollow lined with grass positioned at the end of a grass tunnel. The two to four white eggs are laid at two-day intervals and are incubated solely by the female while the male supplies the food. The females starts incubating as soon as the first eggs is laid and continues for 32–42 days. The female feeds the young taking food brought by the male for the first 10 days; after which, both parents feed the chicks. When the chicks are about four weeks old, the female starts to roost away from the nest. After attaining five weeks of age the owlets begin to wander around the nest, before attempting their first flights at around seven weeks. Once fledged, the young stay with the parents for about 3 weeks, and are independent after that. [3] Prey which are fed to the young are often first decapitated. [8]
African grass owls have been recorded as being preyed on by the African marsh harrier Circus ranivorus. [5]
The African grass owl species is regarded by some authors as the same species as the eastern grass owl Tyto longimembris of Asia and Australia. There are two subspecies of African grass owl currently recognised: [9]
The African grass owl is evaluated as Least Concern. [1] However, in South Africa the species is regarded as vulnerable because habitat degradation through ploughing, grazing, draining and burning; the population in the country is considered to be fewer than 5,000 individuals. [5]
The habitats in which this species breeds and feeds are often alongside areas of human activity, such as industrial, agricultural or mining areas. This causes exposure to various environmental contaminants, for example, metals, which can subsequently be monitored using the birds' feathers. The African grass owl is a good bioindicator species. [6]
To combat their state of vulnerability in South Africa, programmes of captive breeding and release for the African grass owl were tested and studies revealed that this may be a possible effective conservation strategy. However, reintroduction of the African grass owl is not a simple process because supplementary feeding is required and the habitat must be suitable and contain sufficient prey. [11]
The barn owl is the most widely distributed species of owl in the world and one of the most widespread of all species of birds, being found almost everywhere except for polar and desert regions, Asia north of the Himalayas, some islands of Indonesia, and some Pacific Islands. It is also known as the common barn owl, to distinguish it from the other species in its family, Tytonidae, which forms one of the two main lineages of living owls, the other being the typical owls (Strigidae).
The long-eared owl, also known as the northern long-eared owl or, more informally, as the lesser horned owl or cat owl, is a medium-sized species of owl with an extensive breeding range. The scientific name is from Latin. The genus name Asio is a type of eared owl, and otus also refers to a small, eared owl. The species breeds in many areas through Europe and the Palearctic, as well as in North America. This species is a part of the larger grouping of owls known as typical owls, of the family Strigidae, which contains most extant species of owl.
The pearl-spotted owlet is a small bird of prey found in sub-Saharan Africa. They belong to the Strigidae family, otherwise known as the typical owls or the true owls, which contains most species of owl. As part of the genus Glaucidium, or pygmy owls, they are commonly referred to as 'owlets' due to their diminutive size. Pearl-spotted owlets are brownish and heavily spotted white, with two distinct black false 'eyes' at the back of their head. They are often confused with an African barred owlet.
The lanner falcon is a medium-sized bird of prey that breeds in Africa, southeast Europe and just into Asia. It prefers open habitat and is mainly resident, but some birds disperse more widely after the breeding season. A large falcon, it preys on birds and bats. Most likely either the lanner or peregrine falcon was the sacred species of falcon to the ancient Egyptians, and some ancient Egyptian deities, like Ra and Horus, were often represented as a man with the head of a lanner falcon.
The marsh owl is a medium to large species of owl in the family Strigidae.
The red owl is an owl in the barn owl family Tytonidae. It is also known as the Madagascar red owl, Madagascar grass-owl and Soumagne's owl. It is a rare resident of Madagascar that was virtually unknown from its discovery in 1876 to its rediscovery by researchers from the World Wide Fund for Nature in 1993. It is currently listed as vulnerable because of habitat loss, but recent studies have determined it may have a wider range than first believed, though further research in distribution and ecology is required. It has possibly been overlooked because of its close resemblance to the closely related barn owl.
Verreaux's eagle-owl, also commonly known as the milky eagle owl or giant eagle owl, is a member of the family Strigidae. This species is widespread in sub-Saharan Africa. A member of the genus Ketupa, it is the largest African owl, measuring up to 66 cm (26 in) in total length. This eagle-owl is a resident primarily of dry, wooded savanna. Verreaux's eagle-owl is mainly grey in color and is distinguishable from other large owls by its bright pink eyelids, a feature shared with no other owl species in the world.
The spotted eagle-owl also known as the African spotted eagle-owl and the African eagle-owl, is a medium-sized species of owl, one of the smallest of the eagle owls. Its length is 45 cm (18 in) and its weight is from 454 to 907 grams. It has a 100 to 140 cm wingspan. The facial disk is off-white to pale ochre and the eyes are yellow. It has prominent ear-tufts, and the upper body is dusky brown, the lower parts off-white with brown bars. Prior to 1999 the spotted eagle-owl was considered conspecific with the greyish eagle-owl, but now it is classed as a separate species.
The Australian masked owl is a barn owl of Southern New Guinea and the non-desert areas of Australia.
The African pygmy falcon —or simply pygmy falcon—is a diminutive raptor native to eastern and southern Africa. It is the sole species in its monotypic genus, Polihierax. The pygmy falcon is the smallest bird of prey on the African continent, and among the smallest raptors on earth; only the Asian falconets are smaller, weighing roughly 30-40 grams less and measuring about 5 cm shorter from head-to-tail.
The African olive pigeon or Rameron pigeon is a pigeon which is a resident breeding bird in much of eastern and southern Africa from Ethiopia to the Cape. Populations also are found in western Angola, southwestern Saudi Arabia and northern Yemen. It is locally common, although sizeable gaps in its distribution occur due to its habitat requirements.
The Sokoke scops owl is a highly localized species of scops owl found in lowland forests of Kenya and Tanzania. The greatest population of this species of owl is in the Cynometra-Manilkara forest, which is less than one-third of the Sokoke Forest. It is also found in the Afzelia-Cynometra forest.
The fiery-necked nightjar is a species of nightjar in the family Caprimulgidae, which is found mostly in Africa south of the equator, though it has been spotted in a few countries north of the equator. It is most often found in woodland savannas or other deciduous woodlands. It is usually distinguished by its tawny coloured collar which gives the species its common name. It has a distinctive call that many have rendered as 'good-lord-deliver-us'. The fiery-necked nightjar is an insectivorous species that mostly eats butterflies, moths and other insects. The fiery-necked nightjar breeds after the dry season and typically produce two clutches with two eggs per clutch.
The Cape eagle-owl is a species of owl in the family Strigidae. It is one of several large species of the eagle-owl genus Bubo.
The eastern grass owl, also known as Chinese grass owl or Australasian grass owl, is a species of owl in the family Tytonidae. They feed predominantly on small rodents.
Gurney's sugarbird is a medium-sized passerine endemic to the mid- and high-altitude grassland velds in southern Africa. It belongs to the family Promeropidae, which contains one genus, Promerops, and two species. Gurney's sugarbird feeds on nectar from Protea bushes as well as on small insects. This bird is characterized by its long, graduated tail and decurved beak.
The Andaman masked owl is a barn owl endemic to the southern Andaman Islands, an archipelago between India and Myanmar, in the Bay of Bengal. Regarded by some authors as a subspecies of the common barn owl, it is recognized by others as a species in its own right.
The eastern barn owl is usually considered a subspecies group and together with the American barn owl group, the western barn owl group, and sometimes the Andaman masked owl make up the barn owl. The cosmopolitan barn owl is recognized by most taxonomic authorities. A few separate them into distinct species, as is done here. The eastern barn owl is native to southeastern Asia and Australasia.
The western barn owl is usually considered a subspecies group and together with the American barn owl group, the eastern barn owl group, and sometimes the Andaman masked owl make up the barn owl. The cosmopolitan barn owl is recognized by most taxonomic authorities. A few separate them into distinct species, as is done here. The western barn owl is native to Eurasia and Africa.
The American barn owl is usually considered a subspecies group and together with the western barn owl group, the eastern barn owl group, and sometimes the Andaman masked owl, make up the barn owl, cosmopolitan in range. The barn owl is recognized by most taxonomic authorities. A few separate them into distinct species, as is done here. The American barn owl is native to North and South America, and has been introduced to Hawaii.
