SA's vultures are living on a wing and prayer due to drought and soaring temperatures.
In recent weeks vulture sanctuaries and rescuers across the country have been inundated with calls for help as emaciated and dehydrated birds have landed in cities, in gardens and on highways - in one case at the N1 Carousel toll plaza in Pretoria.
Farmers in the Eastern Cape and the Free State report that when they shoot an animal to provide food for vultures, about 200 birds will flock to the carcass now, 10 times as many as normal.
Hardest hit is the Cape vulture, classified as globally endangered with fewer than 4,200 breeding pairs left, and the African white-backed vulture, which was recently recategorised from endangered to critically endangered.
"What is happening to these birds is unprecedented," said Kate Webster of the conservation group VulPro.
"Birds such as the Cape and the white-backed vultures, which are already threatened by man, are being driven to the point of being wiped out."
Webster said that in the past the organisation would get about two calls a month to help stranded fledglings; it was now receiving dozens such calls.
"In December we were called out 23 times. In the first week of January we got called out for 13 birds. While most are fledglings, among the birds we have held are adults, which is concerning," she said.
"One can see from the birds' weight they are starving. A healthy vulture can weigh up to 14kg. The birds we recover are weighing 2kg. They are suffering from calcium deficiencies from the lack of food. They are dehydrated and disoriented."
Webster said climate change and in particular the drought has had a devastating impact on vultures.
"We have found birds searching for food in the Port Elizabeth city centre, one at Pretoria's Carousel toll plaza and in gardens of homes across the country.
"Our staff in North West, in the Magaliesberg area, have been going further and further to rescue birds. At times they have driven up to 600km, which is far beyond [vultures'] normal range, which can be up to 200km with the right weather conditions."
Webster said fledglings are particularly vulnerable because they are weaker than adults.
"When the birds come down they are sustaining severe injuries from bone deficiencies, which are associated with a lack of food. The vultures are basically starving to death. Some are going without food for up to 10 days."
She said drought also posed a threat to vultures' breeding patterns, with the birds only laying one egg a year. They need five years to reach breeding age.
"If this situation carries on we are looking at a collapse of more than 90% in the Cape vulture population within the next 15 years."
Webster said one consequence of the collapse in vulture populations was an increased risk of disease for humans.
"Vultures play a very specific ecological role. They are vacuum cleaners and clean up the environment of diseased animal carcasses," she said. "There is now potential risk of the spread of infectious diseases by feral dogs and other animals feeding off diseased wildlife and livestock carcasses."
Vulture researcher Dr Gerhard Verdoorn also reported a sudden surge in appeals for help from the public.
"Over the past four days my phone has not stopped ringing, with farmers reporting hundreds of birds coming to feed off antelope they have shot for them to eat.
"Under normal circumstances at least 20 birds will feed off a carcass, but some farmers report up to 200 birds coming to feed, which is highly abnormal. This all points to the birds starving."
Verdoorn said that initially the drought had benefited vultures because they could feed on the dead livestock and wildlife.
"But as the drought continues their food supply has dwindled to virtually nothing," he said.
Verdoorn said he was receiving calls for help from farmers over a wide area, including the Kalahari, Botswana and Namibia...