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Jo'Burg Days: The Changing Bird Population Of Johannesburg

Barbara Durlacher reports that climate changes are resulting in variations in the bird life around the city of Johannesburg.

Seen from space, the continent of Africa appears dry and forbidding. It has been drying out for millennia, a process which continues over shorter and shorter cycles as global warming, drought, flood and famine reduce this once fertile land to desert. The serious soil erosion resulting from over-population and over-grazing, denudation of the forests for domestic fuel and charcoal burning and poor farming practices has put great pressures on the land and in many areas the people, vegetation and wild-life are at risk.

Global warming is affecting the continent and from North Africa to Ethopia and south to the Cape it is altering and adapting. Shorter rainy seasons, lower rainfall and harsher and hotter summers have brought about enormous changes in the distribution and spread of plants, animals and birds. Desertification in the Sahara is creeping slowly southwards, but history and the mummified remains of trees show that large forests were once common in this area.

These changes from forest to woodland to grassland have resulted in interesting adaptations where the bird and animal populations have moved into areas where previously they had never been seen. In certain places, patches of woodland with specific isolated bird populations indicate that in former times forest and woodland stretched across large sections and these isolated populations are all that now remains.

In contrast to this desertification, over a period of one hundred years Johannesburg has created the phenomena of extensive areas of Highveld grassland changing to the largest man-made exotic forest in the world. This presents our bird population with one of the largest ranges of mixed exotic shrubs and trees to be found south of the Congo. In providing nesting sites and food sources, it is attracting many varieties of birds previously unknown to this area.

Very few of these shrubs and trees were originally planted with any thought to the effect they would have on the indigenous birds and animals of the Highveld grasslands. In consequence, some species that were unable to adapt have left, whilst other species seldom or never seen in the area are now resident or frequent visitors.

For instance, the Palm Swift is now common in the areas of older Johannesburg where the mop-headed Wellingtonia palms were introduced. The swifts nest in the drooping fronds against the trunk and on warm summer’s evenings can be seen circling and swooping in the rising updrafts, their effortless flight giving a lift to the spirit with their nimble agility.

In contrast, the Capped Wheatear has moved out and is seldom if ever seen, as it is only happy on short over-grazed pasture and in wide-open spaces. The African Grass Owl is already rare and on the endangered list. At present it is widely distributed in the areas along the former eastern gold-reef, now heavily industrialised, with roads carrying dense traffic. So, not only is the bird endangered through loss of habitat, but is frequently killed by uncaring motorists as it crouches at night roosting on the crown of the road.

The Marsh Owl has moved out to areas with shorter grassland, but the extensive mielie lands of the Eastern Transvaal which now occupy hundreds of square kilometres of former undisturbed savannah grassland species, have all contributed to this severe loss of habitat.

In contrast, the Crowned Plover has adapted to the short-grassed playing fields and roadside verges. The birds are sometimes seen nesting in the centre islands of busy roadways, raring their young amongst the roar and fumes of heavy traffic. It can be said that in this bird, adaptation and change has been employed with the greatest skill and success of any of the many new species we are seeing in the Johannesburg conurbation. But, who is to say that urban exhaust pollution, dirty water sources, and contaminated foods will not contribute to newer generations suffering from genetic defects, bone degeneration and weak and damaged eggshells

Garden thrushes are becoming common with large floating populations inhabiting suburban gardens in happy proximity with humans and animals. Observers are inclined to think that specific pairs reside in each garden, but a detailed study has proved that the same bird seldom visits the area twice, many of them ranging far and wide in their quest for food and nesting sites.

Formerly plentiful, and consequently taken for granted, the delightful pied and grey wagtails are now seldom seen, probably due to the unrestrained use of organic phosphate sprays and insecticides in the 1970’s and ’80’s. This decimated the food chain and almost wiped out these delightful little birds. They are slowly recovering, and sightings are getting more frequent in suburban gardens, especially if they have small ponds or open water of any kind, where the wagtails can feed on the tiny insects at the water’s edge which form an important part of their diet.

Whilst the exotic trees grow quickly, they die just as quickly, and thus provide nesting sites for birds with specific requirements. New knowledge and modern thinking regarding the foreign introductions have seen many varieties being eliminated, especially the Australian wattles and blue gums. These water-hungry trees, hundreds of thousands of which were used as windbreaks and to stabilise the poor and shallow soils of the Highveld, as well as providing props for early mining operations, are now considered ‘undesirable aliens’ and are being carefully eliminated. However, many of the more enlightened estate managers and municipalities understand that it is important to keep the larger trees as nesting sites for some of the raptor species, although as indigenous replacement trees mature, the aliens are being removed.

As home gardens proliferated and developed, owners put in fishponds and water features, many of which were well stocked with goldfish and carp. This has proved a ready source of food for kingfishers, cormorants and darters who have quickly discovered the pond populations, with consequent high replacement costs for the homeowner.

Fruit trees in the garden also provide a ready source of food for bulbuls, red faced and grey-speckled Mousebirds, as well as black collared and crested barbets, all of whom are relatively recent new-comers to the Johannesburg scene.

New species have been added to the list of Johannesburg residents as each year passes, grey Loeries which were formerly only seen in the Lowveld, are a resident species; while the formerly exotic Hadidahs, Sacred Ibis, Black Headed Oriole and the Spotted Eagle Owl have become localised. These, together with the ever-increasing population of the Indian Mynahs, which reached South Africa 115 years ago when the first indentured Indians came to this country to work in the Natal sugar cane fields, continue to hold the interest of birdwatchers, who frequently report unusual sightings.

In the last 10 years the beautiful Glossy starling has ventured as far as the Highveld, and has taken up residence, and is one of the few birds brave enough to challenge the Mynahs, occasionally putting these audacious intruders to flight.

The Rameron Pigeon, once rare and in danger of being placed on the endangered list is now quite common, and a population numbering around 500 individuals is known to exist in the Johannesburg environs. Numbers of the African Green Pigeon are also increasing and they are becoming quite a common sight in Johannesburg gardens.

The Woodland Kingfisher has adapted to garden and suburban life and now feeds on insects and small lizards and nests in hollow trees instead of being a burrow-nesting species.

As the drought continues, numerous other Bushveld birds from the warmer areas of the Lowveld are adapting to living in our semi-wooded gardens with their large numbers of large trees, and perhaps in time we may see the beautiful Crimson Breasted Shrike moving quietly and shyly in shrubby cover to join those other compatriots from the warmer areas who have adapted so cleverly to life in the higher and colder areas of this “Ridge of the White Waters”.

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With thanks to well-known bird expert, Geoff Lockwood of The Witwatersrand Bird Club.


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