Africa Wild Bird Book

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A diverse order, owls range in size from sparrow- to eagle-sized. Over 200 species are distributed among approximately 27 genera. Owls are found world-wide, covering nearly all types of terrestrial habitats.
They are known for many characteristics, including their well-developed talons, soft plumage, and notoriously silent flight. Their legs are strong, and feathered in many species; they have zygodactyl raptorial feet. All species have a characteristic facial disk, which is circular among strigid owls and heart-shaped in the tytonid owls. Their holorhinal nostrils are found at the base of their short, downward-pointing bills, and their palates are desmognathous or schizognathous. They have unusually fleshy tongues, and lack crops, but have large caeca with club-shaped ends. Their large wings allow them to fly slowly, and their plumage is often cryptic, and many species have different color phases. Their feathers have either absent or rudimentary aftershafts. Most species are active hunters at night, and as such they have several important adaptations for this lifestyle. Their forward-facing eyes are large, elongated, and have slightly thickened corneas. The number of light-sensitive elements (rods) in their retinas is high, especially compared to other birds. This allows them a heightened sense of vision in dim light, but contrary to popular belief, they cannot see in total darkness. At least some species have been shown to have color vision. Their eyes are more or less fixed in their orbits, supported by a bony sclerotic ring. Therefore they have well-developed binocular vision, but they need to turn their heads to see on either side of them. Their hunting ability is also greatly augmented by their excellent sense of hearing, and some species use their auditory capabilities to hunt prey that they cannot see (such as rodents running under the snow in winter). The facial disk and facial ruff are both important in their sense of hearing. The facial ruff is composed of paired layers of densely packed feathers that have large rachides and reduced vanes; these are inserted behind the ear openings in a special flap of skin. The facial disk, which lies over the ruff, is composed of feathers with open vanes. Together these form parabolic troughs leading to the ears that can increase sound pressure tenfold. The facial ruff and disk are larger in highly nocturnal species, as well as those that hunt prey travelling under the snow. Their hearing is more sensitive to low-frequency sounds than most birds, and is sensitive across a wide range of frequencies. They have a wide outer ear tube and a large inner ear, and the auditory region of the brain has more nerve cells than that of other species of comparable size, which allows them to detect sounds more effectively.
Owls hunt a wide variety of prey, ranging from small mammals to birds, lizards, and insects; there are even fish-eating owls in Africa and Asia. Prey is often swallowed whole, and the fur, feathers, and bones are later regurgitated in pellets. Many owl species, especially those that hunt during night hours, are able to fly nearly silently. Several special feather adaptations make this possible. The leading edges of their outer primaries have stiff, comb-like fringes that reduce noise, the trailing edge of their primaries and secondaries have soft fringes that reduced turbulence behind the wings, and their primaries, secondaries, and wing coverts are covered in downy feathers that also reduce noise. Silent flight may be less important in those species that hunt over water or during the day, and many of these species do not have these adaptations.
Owls do not build nests, instead they use nests of other species or utilize tree cavities. Some nest on the ground and one species nests in underground burrows dug by mammals. In all species the female does the majority, if not all, of the incubation; the male hunts prey and feeds both the female and the young. Females are generally larger than males.

Links:
Africa Wild: Owls of the Kgalagadi
Africa Wild: Owls - Bird of the month December 2013

Two owl families are commonly recognized, the barn-owls (Tytonidae) and the typical-owls (Strigidae).

ORDER STRIGIFORMES
Family Tytonidae (Barn Owls)
Family Strigidae (Owls)

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This family of owls includes two extant genera and approximately 16 species. They are found mainly in tropical regions, with several species, including the common barn-owl, ranging to higher latitudes. Most species are forest-dwelling, though several species are found in open woodland areas, and the grass-owls live in open grasslands.
Morphologically, the tytonid owls vary from their strigid relatives in several characteristics. These owls have a heart-shaped facial disk, an elongated, compressed bill, and proportionately smaller eyes than Strigidae owls. They have long legs, and their inner toe, which is as long as the middle one, has a pectinate claw. Their sternum has two notches and is fused with the furcula. Like the other owls, however, their talons are well developed, and their fourth toe is reversible. Females are generally larger than males, and may have darker spots. Their plumage is soft and dense, generally darker with markings on the upperparts, while the underparts are pale and often without any markings. As in all owls, they have an unusually fleshy tongue and well-developed intestinal caeca, and they lack a crop as found in most birds.
The tytonid owls are perhaps best known for the well-studied common barn-owl, Tyto alba. Many other species are known little, if at all, and we can only assume that their behavior patterns are similar. Tytonid owls tend to feed on small mammals when available, with rodents, shrews, and voles important in the diet. However, they are capable of adapting to locally available prey, and have been known to prey on many species of birds, especially shorebirds, as well as reptiles, frogs, and insects. They often carry their prey in their bill, unlike other birds of prey that carry their prey in their talons.
Most species can fly nearly silently; there are several feather adaptations that allow this to happen. They have large, broad wings that allow slow flight; many species will hunt while slowly soaring near the ground. Most species within this family are nocturnal, and their excellent vision and hearing allows them to hunt with high accuracy in very poor light. They tend to remain solitary or in pairs throughout the year, and may occupy a territory year-round; most species are sedentary and after fledging do not travel far from their natal site. Again, much of what we know about reproductive behavior comes from the common barn-owl, which may have low breeding rates, especially in unfavorable conditions. Egg-laying varies with weather and prey cycles, so that females will lay eggs when their prey species are also reproducing. Clutch sizes are variable within the family, ranging from small (1-2 eggs) to larger clutches (4-7 eggs). Most species within this family nest in tree cavities, barn-owls may take advantage of man-made structures such as barns and church steeples. The grass-owls nest on the ground, burrowing a system of tunnels through long grasses to a nesting site. Females are usually the sole incubators, while the males provide food, though both will care for the young once hatched. Sensitive to disturbance, the tytonid owls are known for their threat displays. When confronted with danger, the owl will bow towards the intruder, spreading its wings and tail, hissing and snapping its bill; if the intruder is not frightened off, the owl will proceed to move its head up and down while shaking it, still hissing. The bowing and head shaking aspects of the threat display seem to be unique to this family.

Family Tytonidae (Barn Owls)
Tyto alba Western Barn Owl 392
Tyto capensis African Grass Owl 393

[Dewi]

392. Western Barn Owl Tyto alba (Nonnetjie-uil)
Order: Strigiformes. Family: Tytonidae

Barn Owl Tyto alba.jpg (24.42 KiB) Viewed 1195 times

Description
A pale, long-winged, long-legged owl with a short squarish tail. Creamy white underparts, golden brown upperparts with grey, black and white mottling. Distinctive heart shaped facial disc, the eyes are black. The bill is dark pinkish-grey and the talons are black. Females are larger than males.
They have acute hearing, with ears placed asymmetrically for improved detection of sound position and distance.
This owl could be confused with African Grass Owl but is much paler and has less contrast between the upperparts and the underparts.

Distribution
Tyto alba is the most widely distributed species of owl in the world and is found on every continent except Antarctica. Found throughout the sub-region, but scarcer in the Southwest.

Habitat
Varied. It can be found anywhere that has abundant food and suitable roost sites, but it generally prefers grasslands, savannas and arid regions, often near human habitations.

Diet
It hunts by flying low and slowly over an area of open ground, hovering over spots that conceal potential prey. They feed primarily on small vertebrates, particularly rodents. Studies have shown that an individual Barn Owl may eat one or more rodents per night. A nesting pair and their young can eat more than 1,000 rodents per year. Usually, its diet consists of 75 - 97% rodents, with the rest largely made up of shrews and small birds. In urban areas, however, small birds dominate its diet, making up 40 - 95% of prey items. In desert areas, it tends to eat a lot of geckos and scorpions. It usually catches its prey by sitting on low branches, using its powerful hearing to locate small animals. Once it has heard something, it swoops silently down to the ground, grabbing the prey with its talons.

Breeding
Barn Owls normally pair for life. It does not build its own nest, but instead most commonly uses man-made structures, tree hollows and caves. It often uses the same nesting site over many seasons. Egg-laying season is year-round, peaking from August to December in the Western Cape and from February to May elsewhere in South Africa. An average of six white eggs are laid per clutch, but can be as high as 19 eggs in boom years, when prey availability is high. The female incubates the eggs for 29-34 days, while the male hunts and brings food to the nest. Incubation starts with the first egg so, since there is 1-3 day interval between laying, there are always chicks of different ages in one brood. This means that sometimes older chicks feed the younger ones but, when food is scarce, the older ones are capable of eating their siblings. The chicks stay in the nest for 45-55 days before fledging. Juveniles often return to the nest a week after learning to fly, and are able to hunt about three weeks later.

Call
A characteristic shree scream, which is ear-shattering at close range. Males in courtship give a shrill twitter. They also hiss like a snake to scare away intruders. Listen to Bird Call.

Status
Uncommon to locally common resident.

[Dewi]

392. Western Barn Owl Tyto alba

© Dewi

© Dewi

© Dewi
Kgalagadi Transfrontier Park

© Michele Nel
Kgalagadi Transfrontier Park

© Duke
Kgalagadi Transfrontier Park


Kgalagadi Transfrontier Park

© ExFmem

Links:
http://sabap2.adu.org.za/docs/sabap1/392.pdf
http://sabap2.adu.org.za/spp_summary.ph ... &section=3
http://www.oiseaux-birds.com/card-barn-owl.html

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393. African Grass-owl Tyto capensis (Grasuil)
Order: Strigiformes. Family: Tytonidae

African Grass-owl Tyto capensis.jpg (31.71 KiB) Viewed 1206 times

Description
Size: Length 38-42 cm. Wing length 28-35 m. Weight 355-520 g. The upperparts are dark brown with pale spots, with buff bars in the wings, which can appear bluish-grey in flight. The underparts are creamy white to pale buff with some brown spots. The tail is short, with the central feathers uniform brown, and outer feathers becoming paler (almost white) towards the edges, and showing about 4 dark bars. The facial disc is white, with a thin yellowish-buff rim that is densely spotted dark. There is a brown mark in front of each small brown eye, with the edge of disc dark brown on top but buff on sides and bottom. The bill is light brown. The eyes are brown. Legs are feathered whitish to the lower third of the tarsi. The remainder of the tarsi and the toes are slightly bristled and coloured pale yellowish-grey. Claws are dark greyish-brown to blackish.
The female is larger than the male.
Similar species: Told from Western Barn Owl by being larger and having darker upperparts, with stronger contrast between the upper and lower body. The face is also rounder than the Western Barn Owl.

Distribution
It occurs in patches of sub-Saharan Africa, from the Congo and northern Angola through southern DRC to Tanzania, Zambia, Malawi and southern Africa. Within southern Africa it is locally common in north-central Zimbabwe, western Mozambique, eSwatini and east-central South Africa.
Grass Owl chicks are rescued from veld fires and rehabilitated onto Suikerbosrand Nature Reserve in the Gauteng province of South Africa.

Habitat
It generally prefers marshes and vleis with patches of tall rank grass, weeds or sedges, but it may also occupy fynbos, renosterveld and thorn scrub close to water.

Diet
Mainly eats rodents, foraging nocturnally by flying low over the ground, twisting its head in order to locate by sight and sound. Once prey is located it dives to the ground and picks it up with its talons, feeding on the ground or on a nearby perch.

Breeding
Probably a monogamous territorial solitary nester. Breeds from from November-July, peaking from January-April. The nest is a shallow hollow lined with grass at the end of a grass tunnel. 2-6 white eggs are laid, averaging 41.1 x 32.7 mm, normally at 2 day intervals. The female incubates the eggs alone, while the male supplies the food. Incubation starts with the first egg and lasts 32-42 days. The young are fed by the brooding female using food brought by the male for about 10 days; thereafter, both parents feed the chicks. When the nestlings are about 4 weeks old, the female no longer roosts at the nest. At 5 weeks the young begin to wander around the nest, and then at 7 weeks they make their first attempts at flying. After leaving the nest, the young remain with the parents for about 3 weeks, before becoming independent.

Call
A screeching call similar to the Barn Owl, but less strident. Another typical call is a fast frog, like series of 'clicks'.

Status
Uncommon resident. Tyto capensis is considered Vulnerable in South Africa, with between 1 000 and 5 000 birds remaining in this country. The species is extirpated in south-western South Africa and Lesotho, and the combined pressure from development; fire mismanagement; land clearing for agriculture; overgrazing; afforestation and roadkill are of serious concern for the species.

[Amoli]

393. African Grass-owl Tyto capensis (Grasuil)



Links:
Species text Sabap1: http://sabap2.adu.org.za/docs/sabap1/393.pdf
Sabap2: http://sabap2.adu.org.za/spp_summary.ph ... &section=3
David Allan. A Photographic Guide to Birds of Prey of Southern, Central and East Africa: http://books.google.de/books?id=07q31oQ ... le&f=false
Peter Steyn: A Delight of Owls: African Owls Observed
Jenkins, A. 2010. Focus on South Africa’s threatened birds: African Grass-Owl. Africa - Birds & Birding 15(3):34-35.
Interview with Craig Whittington-Jones about the African Grass Owl

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The family Strigidae is the larger of the two families of owls, with close to 190 species distributed among 25 genera. The internal taxonomy is very complicated, owing in part to the similarities between species, and in part to the fact that many have been little studied. They are found worldwide, on every continent of the world except Antarctica, but 80% of the strigids are found in the tropics. Strigid owls cover nearly all terrestrial habitats, though 95% are forest-dwelling species. Most of the typical owls are non-migratory.
The strigid owls are a diverse family, ranging in size from 40 g to 4 kg. They differ from their tytonid relatives in a number of minor osteological features. The characteristic facial disk in strigid owls is circular, rather than heart-shaped, and their eyes are relatively larger. Many species have thickly feathered legs; their well-developed talons have a smooth edge on the claw of the third toe (in contrast to the pectinate claw of the tytonids), which is longer than the second toe. These owls have large heads, large, slightly elongated eyes, a short, hooked bill that points downwards. Their sternum has four notches, and is not fused with the furcula. Nonetheless, they do share many features with their tytonid relatives. They have large wings and strong legs. Their talons are sharp and hooked and their feet are zygodactyl with a reversible fourth toe. Plumage is soft and dense; feathers lack an aftershaft and have a downy base. Strigids tend to be cryptically colored and some species have dark nape patches that resemble false eyes. Many species have ear tufts that have been suggested to have behavioral functions; they do not function in sound acquisition.
Strigid owls feed on a variety of prey items, with small mammals forming a large part of the diet of some species. Eagle owls, the most powerful of strigid owls, can even handle larger mammalian prey such as foxes, young roe deer, and monkeys. However, not all species focus on mammals. Many are insect specialists, some hunt birds or bats, and both the fish-owls and the fishing-owls prey mainly on freshwater fish. Although several of the strigids hunt during daylight, all species are nocturnal to some degree. Like the tytonid owls, they are well-adapted to hunting under low light conditions. Their eyes have many more rods than cones, which is unusual compared to most birds,and makes them more sensitive to light. The eyes are long and are more or less fixed in place, supported by a bony sclerotic ring. Their hearing is extremely sensitive, owing in part to the structure of their facial ruff and disk, and many species have feather adaptations that allow them to fly nearly silently.
Courtship involves aerial displays in some species; in many others it may only involve ritualized feeding in which the male brings food to the female. The owls are extremely adverse to building nests; they will utilize nests of other species or tree cavities; some species nest on the ground. Some smaller species are very particular in the their nesting choices, nesting mainly in cavities excavated by woodpeckers. The burrowing owl is unique in that they nest in underground burrows dug by mammals. Females generally lay a clutch of 4-7 eggs, though some smaller species have smaller clutches, and in times of abundant food, some species may lay larger clutches. In the northern saw-whet owl the female may reach 150% of her non-breeding body mass while egg-laying! Females usually begin incubating with the first egg laid, resulting in a large size skew among young once all are hatched. Once incubating, females will generally leave the nest only once or twice a night to defecate; the male will provide food to the female and to newly hatched young. Females will not resume hunting until later in the brood-raising period. Because they are the only incubators, females are usually the primary nest-defenders in the face of an enemy. Some species are extremely aggressive towards humans, especially during this crucial period. When threatening an intruder, the owl will crouch down, lower its head, droop its wings, and ruffle its feathers. It will usually vocalize or bill-clap as well, in an effort to scare away the unwanted visitor or predator. Most of the strigid owls spend their time alone or in mated pairs all year. Only four species are considered 'social' when breeding, though none are truly colonial. Several species roost in colonies during the winter.
The strigid owls have been divided into 2 subfamilies; Buboninae (with ~21 genera) and Striginae (with 6 genera). A current classification, based on skull morphology, divides them into 3 subfamilies; Striginae (13 genera), Surniinae (8 genera), and Asioninae (2 genera).

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Family Strigidae (Owls)
Otus senegalensis African Scops-owl 396
Ptilopsis granti Southern White-faced Scops-owl 397
Bubo capensis Cape Eagle-Owl 400
Bubo africanus Spotted Eagle-Owl 401
Bubo lacteus Verreaux's Eagle-Owl 402
Scotopelia peli Pel's Fishing-Owl 403
Strix woodfordii African Wood Owl 394
Glaucidium perlatum Pearl-spotted Owlet 398
Glaucidium capense African Barred Owlet 399
Asio capensis Marsh Owl 395

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396. African Scops-Owl Otus senegalensis (Skopsuil)
Order: Strigiformes. Family: Strigidae

African Scops-Owl Otus senegalensis.jpg (26.11 KiB) Viewed 1203 times

Description
Length 14-18 cm; weight 45-97 g. The African Scops-Owl is the smallest owl in southern Africa, smaller in size than a dove. Heavily streaked, grey owl with ear tufts. The face is surrounded by black edging.
Similar species: Most like Southern White-faced Scops-Owl but only about half the size with grey face, not white.

Distribution
Sub-Saharan Africa. In southern Africa it is locally common in northern and central Namibia, Botswana, Zimbabwe, Mozambique and northern and south-eastern South Africa.

Habitat
Arid savanna woodland, especially Mopane and Acacia.

Diet
Mainly insects (such as scorpions, cockroaches, millipedes, grasshoppers and crickets) and spiders, also small rodents, birds, geckos and frogs.

Breeding
Mainly nests in natural tree cavities 1.2-9 m above ground, usually where the trunk has snapped off, a branch has broken off, or a hole has been rotted in into the tree. Egg-laying season is from June-November. It lays 2-4 eggs, which are incubated by the female for about 22 days. The male hunts for both of them. For the first 12 days of their life they are brooded by the female, after which both sexes do the hunting. The chicks leave the nest when they are 75% of the adult size, at about 25-28 days old.

Call
A frog-like prrup repeated every 5-8 seconds; often for several minutes. Listen to Bird Call

Status
Common resident.

[Sprocky]

396. African Scops-Owl Otus senegalensis (Skopsuil)

African Scops-Owl.jpg (65.67 KiB) Viewed 1215 times

© Sprocky

© Flutterby

© JustN@ture

Links:
Species text Sabap1: http://sabap2.adu.org.za/docs/sabap1/396.pdf
Sabap2: http://sabap2.adu.org.za/spp_summary.ph ... &section=3
Oiseaux net: http://www.oiseaux-birds.com/card-afric ... s-owl.html
Sasol Birds of Prey of Africa
Smit, B. & McKechnie, A. 2008. Cold comfort: the secret life of African Scops-Owls. Africa - Birds & Birding 13(5):42-46.
Peter Steyn: A Delight of Owls: African Owls Observed
NEWMAN'S VOELS VAN SA (8ste UIT): http://books.google.de/books?id=dOTi7T8 ... se&f=false