CHALLENGES TO GROUND HORNBILLS AND THEIR RECOVERY

 

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This section addresses the multitude of threats that face the species.

HABITAT LOSS: The primary threat to the species is loss of habitat. This affects both quality of foraging habitats and loss of suitable breeding sites through human exploitation of trees, thus reducing the number of available nest sites [1]. Over-utilization of savannas, leading to loss of ground cover and/or encroachment of woody bushes, and afforestation of grasslands, both lead to reduction in the quality and area of foraging habitat available to the hornbills. This is coupled with expanding human settlements and plantations that further seriously reduce the amount of useful habitat.

LOSS OF NESTING TREES: The hornbills need a tree with a cavity with an internal diameter of at least 40cm. The aptly named Leadwood is the most frequently used and long-lasting tree nest site in South Africa, but the softer-wooded fig, ebony and marula are also used and, where it occurs, the mighty baobab. Conservation of these key tree species is as important as caring for the hornbills themselves.  Where hornbills nest in cavities on cliffs there less chance of their site being damaged or lost.

INDIRECT POISONING: Whole groups have been eliminated by indirect poisoning during campaigns against livestock-predators and rabies-carriers, to which their systematic terrestrial foraging makes them especially prone. Poison is also used directly against problem birds, or eaten indirectly when bait for other birds such as vultures is poisoned.

TRAPPING: Secondary trapping and snaring is also a probable cause for the same reasons, but has been rarely reported so far.

DIRECT PERSECUTION: Unfortunately these hornbills are persecuted in developed areas, where their aggressive territoriality leads to attacks on and shattering of their reflection in window panes, often leading to the birds being destroyed (Kemp 2000). Lodges, farm houses and rural schools are targeted particularly during school holidays/off seasons when there is no human disturbance to keep the birds away. We are working on a number of methods to dissuade hornbills from breaking windows.

 

TRADITIONAL USE:  Body parts are used for traditional practices associated with rain-making, mainly during drought.

ELECTROCUTION: Electrocution on power lines and transformer boxes. Four released  birds were electrocuted on transformer boxes and we are working with ESKOM to safe-guard all future release sites.

LIVE TRADE: the trade in exotic birds to supply zoos are also thought to have an impact, particularly in Tanzania.

LIFE HISTORY:  Their  life-history strategies;  like those of all large  top-order  predators;  makes them  vulnerable to  extinction.  They have slow-breeding rates,  (groups fledging one chick every nine years on average in South Africa),  delayed  sexual maturity and high juvenile mortality,   which makes them  susceptible to persecution and slow to recover from its effects [2]. Southern Ground Hornbill are also limited by availability of food.
 
[1]   Johnson et al. 1998 in BBC Wildlife May 1996
[2]  Kemp 2000