African Wildlife & Environment Issue 81

BIRDING

often sing together. The Northern White-faced Owl has a quite different two-note call, and will not be mentioned anymore in this article.At night, their bubbling hoots or cat-like alarm calls will often give their position away, making it easier for rangers and trackers to pinpoint their location. During the day they roost in the canopies of trees, their colouration and quiet pose making them very difficult to detect. Temperature adaptability: During the winter the owls increase their resting body metabolic rate (BMR) by approximately 45% to adjust to the climate changes. Furthermore, the owls do this to increase cold temperature tolerance which, is unusual for these creatures. Not only that, but the BMR of the owl is lower than what is expected, when compared to other birds like them, to help them when there is a lack of food. This is unusual considering the lack of food and other survival resources during the winter. Distribution and habitat: range extends from Gabon eastwards to southern Kenya and southwards to Namibia and northern South Africa. It inhabits savanna and dry woodland; it is found in a wide range of habitats, from drier broadleaved woodland, dry acacia thornveld savanna to moister forest fringes.

The Southern White-faced Owl quite cleverly emulating a tree (Photo: John Wesson)

If alarmed they have a unique way of escaping detection; they can elongate their bodies and contract their plumage, making themselves taller and thinner - and even lean slightly to further camouflage themselves as branches. At the same time, they narrow their very bright eyes into slits, making their faces less visible. To create the illusion of being much larger and more aggressive, they will open and raise their wings, creating a large 'semi-circle' around their bodies - and then fluff out their feathers to further increase their apparent size. Their call is a series of fast, bubbling hoots. This call is uttered at night and frequently repeated. These fast, staccato notes followed by a longer and higher pitched 'hoot " and described as " Hu-hu-hu-hu-hu-hu Hooo-hu " are extensively used during the breeding season and pairs of owls

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