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Saturday, 9 February 2013

Predators of the African night


With their haunting calls and silent flight, owls are among the most elusive and misunderstood of all birds. Legends and fables from across the world describe the owl as a supernatural being, often associated with death, while in other cultures, the owl is revered as being “wise”. But certainly the owl must be one of the most important birds in our ecological system. Without them, the world would be overrun by mice and rats. 

I, for one, rely heavily upon owls to keep the rat population in control and therefore don’t use any poisons at all. Smallholdings always have a rat problem, as there is plenty of food for them and, of course, storage places for food like barns and open store rooms are an open invitation to these rodents.

Africa supports a large number of owl species – between 30 and 40, with new species of forest-dwelling Scops Owls still being described, and some of them are among the most interesting birds on the continent. All serious bird-watchers yearn to catch a glimpse of a Pel’s Fishing Owl, while the Congo Bay Owl may be one of the world’s rarest species. The evocative frog-like call of the common Scops Owl is as characteristic of the savannah night as the whoop of a hyena.

Owls are generally characterized as being birds of prey of the order Strigiformes. On silent wings, Owls catch their food primarily at night. The large eyes that face forward allow this bird to have binocular vision, enabling it to judge distances between objects and maneuver through crowded environments.

The eyes of these birds are immovably fixed in their sockets. In order for the birds to follow moving objects it must turn its head. Because they have long flexible necks, they can turn their heads 260 degrees.

Their flight feathers are serrated at their tips, which has the effect of muffling the flapping sound of their wings during flight.

Few bird of this species hunt prey in full daylight, so their hearing is particularly important. Many have asymmetrical skulls, with the ear openings at different levels. The right ear is positioned high on the head, while the left ear is low. 

There are about 162 different species of owls alive today, 12 of which occur in Southern Africa, inhabiting a huge variety of ecological niches, from rainforests to tundra. Some owls have feathered ear tufts; these are not ears, but are part of the owl’s camouflage.

Owls feed entirely on living animals, with the size of the prey proportional to the size of the bird, from insects to mammals as large as hares. Like most other raptors, these birds have sharp talons for seizing and holding prey.

W&N watercolour - Maree Clarkson

Their hooked beak is designed for tearing meat. Any food that is indigestible to these birds, such as bones, hair, and feathers, are compressed and regurgitated as compact pellets. These pellets can aid in understanding what the birds eat by analyzing the contents within them.

The nesting habits of these birds vary considerably. Some nest in large tree nest or among rocks, others are cavity nesters living in holes in trees. Barn owls can be attracted to man-made bird houses. Since the decline in this birds natural habitat, farmers have begun using bird houses placed on poles or the side of barns and other outbuildings to attract more of these beneficial birds. The reason for wanting to attract these birds is to control rodent populations. This minimizes the need for chemical poisons.

During the nesting season, these birds work tirelessly hunting mice to feed the young, thus helping both the owl and the farmer. All birds of this species lay pure white eggs. These are laid over a period of several days and incubation begins with the laying of the first egg. The first eggs to hatch will have a better chance of survival than the later. Older nestlings will be able to compete for food over the younger and smaller birds in the nest. Nestlings have enormous appetites and can eat their own weight in food in a single night.

Trying to locate owls can be difficult since their movement during daylight is minimal. Their well-camouflaged feathers help them blend in with their habitat.
Some of this info from Wild Bird Watching.com

Either way, I think owls are birds worth the effort to study, watch and conserve.

Barn Owls often make use of my nest boxes, which might be an indiction that their nesting territory is shinking. Artificial nest boxes will also be used by Eagle Owls and Scops Owl. Barn Owls and Spotted Eagle Owls live in close proximity withg humans and therefore seem to accept nest boxes put up in trees or against buildings. 

The Barn Owl (Tyto alba) is one of our owl friends that saves us from being over-run by rats.

African Scops Owl

The African Scops Owl is a common, sometimes abundant, resident of Savannah woodland in South Africa. Scops Owls feed mostly on insects and spiders and breed in a tree cavity.

The Scops Owl is fully nocturnal and mostly insectivorous. It is a bird of scrub and bush territory, and often uses ground nest sites for breeding. It is a small owl of only about 17cm and lays its 4-6 eggs in a tree cavity from April – June. Incubation about 27 days. Young fledge by about 30 days. Its call is a soft croaking, frog-like “prrrup-prrrup”.

Giant Eagle Owl – ElizabethKendall

The modern West generally associates owls with wisdom. This link goes back at least as far as Ancient Greece, where Athens, noted for art and scholarship, and Athena, Athens’ patron goddess and the goddess of wisdom, had the owl as a symbol.

The Giant Eagle Owl is the largest owl in the world. As the biggest of all the Owls the Eagle owl is easily recognised by its huge size and wingspan. They are light grey in colour, finely bared blackish above and below but no heavy blotching. The face is pale, boldly outlined in black, eyes look black at a distance and they have distinctive pink eyelids, which makes them very identifiable. Very similar to a huge Long Eared owl. The Eagle Owl is a pale sand colour underneath with streaks of dark Brown or grey. Greyish head with a large powerful beak and large orange or yellow eyes and two ear tufts extending from over the eyes. They have huge powerful feet and talons.


Tyto alba – Barn Owl. - Elizabeth Kendall

These pale, nearly worldwide, birds are closely associated with man through their traditional use in the Old World of barn lofts and church steeples as nesting sites.

Barn owls (Tyto alba) roost and nest in old barns, ruins and neglected buildings as well as in trees and sometimes cliffs. They have a long breeding season starting in early Spring and may rear two broods.

Barn Owl hunting - Maree Clarkson©

The size of each clutch can vary from as few as three to as many as eleven but is usually between four and seven, depending on the supply of food available. The male will feed the female while she is incubating the eggs, a period of about five weeks.

The young owls are born covered in white down and twelve days later develop a creamy coat which will eventually be shed to develop the characteristic golden upper coat mottled with grey and the white under feathers of the adult. The young owls are ready to fly at eight to ten weeks old.

Although widely known beforehand, it was in 1769 when the Barn Owl was first officially described by Giovanni Scopoli, an Italian naturalist. The species name “alba” also refers to the colour white. Other names for the Barn Owl have included Monkey-faced Owl, Ghost Owl, Church Owl, Death Owl, Hissing Owl, Hobgoblin or Hobby Owl, Golden Owl, Silver Owl, White Owl, Night Owl, Rat Owl, Scritch Owl, Screech Owl, Straw Owl, Barnyard Owl and Delicate Owl.

They occur throughout most of Britain and Europe and across many parts of Asia, Africa, and in much of North America. In South America they are found in areas of suitable grassland, as well as on oceanic islands such as the Galapagos. They were introduced to Hawaii in 1958. 

For more information on owls and some lovely photographs, please visit my Saturday Chat which I do once a month in a group on Redbubble. 

 A Marsh Owl on a fence-post on our property - Maree Clarkson©

I’m lucky enough to have three owl-species either residing or visiting our smallholding here in South Africa – the Spotted Eagle Owl (Bubo africanus), the Barn Owl (Tyto alba) and the very shy Marsh Owl (Asio capensis). 

My greatest joy is hearing the ‘Whoo-whoooo’ of the Eagle Owl on my roof in the middle of the night or the ‘Screeeeeech’ of the Barn Owl just before dawn. And, rarely, the rasping whistle of the Marsh Owl. It is actually easier spotting him in the day where he roosts on a, sometimes fairly low, branch in our blue gum bush or on a fence post. At night his stealth and silence makes him virtually impossible to discover. I doubt if he is a resident on my property, as they nest on the ground in a shallow, unlined scrape amongst vegetation and, besides the tall blue gums, the property is mainly grassland. 

The Marsh Owl, Asio capensis, is a species of owl which is a mainly resident breeder in Africa and Madagascar. The call is a frog-like “kaar”, said to resemble the noise made by slowly bending and breaking a branch or rasping whistle “shrss” The conservation status is LC (Least Concern). 

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1 comment:

  1. Just a quick noteI wound up going with a dark black/brown counter. I will post photos in a later update.
    red onyx tile

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