South Africa's Bustards
Threatened
South Africa's bustards are in trouble,
with six of the country's ten species listed in the South African Red
Data Book. "They are threatened by a variety of factors", says Mark
Anderson, Executive Director of BirdLife South Africa ".with some of
the most important threats being habitat destruction and power-line
mortalities".
BirdLife South Africa is concerned about the precarious
conservation status of the country's bustards and korhaans. At a
workshop in Johannesburg in May, the status, threats and necessary
conservation measures relevant to these birds were discussed by the
country's bustard experts.
Pop ulations of Ludwig's Bustard and
Denham's Bustard are probably in decline due to a single mortality
factor, collisions with the cables of power-lines. "These birds fly in
groups during low light conditions and due to their limited manoeuvrability are not able to avoid electricity cables in their
flight path", says Jon Smallie, Manager of the Endangered Wildlife
Trust's
(EWT) Wildlife Energy Interaction Group (WEIG)
and the Eskom-EWT Strategic Partnership. Studies by Mark Anderson and
the University of Cape Town's Dr Andrew Jenkins, have found that, on
average across six patrolled sites, about one Ludwig's Bustard
collides per kilometre of power-line per year at these sites. There
are approximately 16,000 km of transmission (>132000volts) power-lines
criss-crossing the Karoo indicating the potential severity of this
problem. The Eskom-EWT Partnership's Central Incident Register
documents no less than 265 confirmed Ludwig's Bustard mortalities from
power-lines. In response, Eskom is currently funding research into
bustard collision rates, movement patterns and visual acuity - all
critical aspects if we are to mitigate this threat. According to David
Allan, ornithologist at the Durban Natural Science Museum and a world
authority on the biology of bustards, "The global population of
Ludwig's Bustard has been estimated to only number between 56,000 and
81,000 individuals. The thought that we could be potentially losing
them at a rate of over 10,000 birds killed annually by this factor
alone is terrifying".
The Blue Korhaan, which mainly inhabits grasslands in the
central and eastern regions of South Africa, is severely threatened by
afforestation, crop farming, overgrazing, burning, urbanization and
mining. Analyses of information from the Coordinated Avifaunal
Roadcount Project (CAR) suggest that this korhaan has ".declined in
both numbers and range during recent years", stated Donella Young, the
CAR coordinator at the University of Cape Town's Animal Demography
Unit. The Blue Korhaan is only found in South Africa and marginally in
western Lesotho, so we have an important obligation to protect this
localized species.
The White-bellied Korhaan, another species that is restricted to
the grasslands and open thornveld, is listed as *Vulnerable* in the
South African red data book. It prefers tall, undisturbed grassland,
and is thus threatened by human population pressure and inappropriate
farm management. The White-bellied Korhaan is also found in central,
west and east Africa, but there is some debate about whether the South
African population is a separate species (Barrow's Korhaan). If
genetically distinct, there is even more pressure on South African
conservationists to attend to the numerous threats which are impacting
on this threatened species.
It was decided at the bustard workshop, which was made possible
through funding from E. Oppenheimer & Son, that a Bustard Working
Group would be formed under the auspices of BirdLife South Africa. The
group will have several aims, but will focus, at least initially, on
disseminating information about bustards to the relevant authorities
and stakeholders, prioritizing research needs, and determining urgent
conservation interventions.
Mark D. Anderson
Executive Director BirdLife South Africa
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