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Sep 07 2011

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Marsh Owl (Asio capensis)


Marsh Owl

[order] STRIGIFORMES | [family] Strigidae | [latin] Asio capensis | [authority] Smith, 1834 | [UK] Marsh Owl | [FR] Hibou du Cap | [DE] Kap-Ohreule | [ES] Buho Moro | [NL] Afrikaanse Velduil

Subspecies

Monotypic species

Genus

Asio is a genus of typical owls, or true owls, in family Strigidae. The genus Asio contains the eared owls, which are characterised by feather tufts on the head which have the appearance of ears. This group has representatives over most of the planet, and the Short-eared Owl is one of the most widespread of all bird species, breeding in Europe, Asia, North and South America, the Caribbean, Hawaii and the Galpagos Islands. Its geographic range extends to all continents except Antarctica and Australia. These are medium-sized owls, 30?46 cm (12?18 in) in length with 80?103 cm (31.5?40 in) wingspans. They are long winged and have the characteristic facial disc. The two northern species are partially migratory, moving south in winter from the northern parts of their range, or wandering nomadically in poor vole years in search of better food supplies. Tropical Asio owls are largely sedentary. Asio owls are mainly nocturnal, but Short-eared Owls are also crepuscular. Most species nest on the ground, but the Long-eared Owl, Asio otus, nests in the old stick nests of crows, ravens and magpies (family Corvidae) and various hawks. These owls hunt over open fields or grasslands, taking mainly rodents, other small mammals and some birds.

Physical charateristics

The Marsh Owl is 35-37 cm in length with an 82-99 cm wingspan. It is similar to the slightly larger Short-eared Owl. It has yellow eyes with a black iris, and short ear-tufts which are not usually visible. It is distinguished from its relative by its dark brown plumage, and almost unstreaked upperparts. It is long winged, and glides slowly on stiff wings when hunting. It will often perch on the ground or low posts.


wingspan min.: cm wingspan max.: cm
size min.: 29 cm size max.: 36 cm
incubation min.: 14 days incubation max.: 18 days
fledging min.: 27 days fledging max.: 18 days
broods: 1   eggs min.: 2  
      eggs max.: 4  

Range

Africa : widespread

Habitat

As it name suggests, it is often associated with marshes, however it also occurs in tall grassland, reeds, sedges and Acacia woodland.

Reproduction

It nests in a slight depression in the ground, surrounded by dense grass and weeds, making it difficult to find.
Egg-laying season is from October-December in Botswana, and mainly from March-April elsewhere in southern Africa.
It lays 2-6, usually 2-4 eggs, which are incubated solely by the female, for about 27-28 days. The male does all the hunting, storing his prey in “caches”, to be eaten later by either him or the female.
The chicks stay in the nest for about 14-18 days, after which they crawl around the surrounding bush for a few weeks, at least until they learn to fly. The fledglings are thought to remain dependent on their parents until they are about 80 days old.

Feeding habits

Its food is mainly insects, but it will take small mammals, such as rodents and birds. Usually hunts in the day, eating insects but also small vertebrates. When hunting, it flies low over the ground, searching for prey, occasionally swerving or hovering. Once a prey item has been spotted, it rapidly dives to the ground, picking it up with its talons before storing it in a nearby hiding place, to be eaten later.

Video Marsh Owl

copyright: J. del Hoyo


Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
It occupies an area from Ethiopia to southern Africa, where it is uncommon to locally common in Botswana, Zimbabwe and large areas of South Africa, especially in the Kruger National Park
Marsh Owl status Least Concern

Migration

Resident throughout range

Distribution map

Marsh Owl distribution range map

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