Big drop: The cliff-nesting Taita falcon is in danger of being wiped out, research shows. Picture: Supplied
In late July, ornithologist Anthony van Zyl was among a team of researchers perched along the edges of the Batoka Gorge system, downstream of Victoria Falls. Their mission? To locate the cryptic Taita falcon, one of Africa’s rarest and most elusive raptors.
With binoculars and telescopes trained on the cliffs the group, including eight teams from Zambia and five from Zimbabwe, scanned the horizon. But not one sighting of the cliff-nesting, bird-eating raptor was made.
“We saw plenty of other raptors, but not a single Taita falcon,” said Van Zyl. “For me, it really shows that while the Batoka Gorge used to be quite a stronghold for these birds, that population is now gone.”
He fears South Africa’s population of the small, stocky and little-known bird is headed the same way. It is one of the country’s rarest breeding birds and is listed as critically endangered.
“I honestly feel that this is going to be the case for the South African population too; that we used to have a whole lot and now, over the years, the population is snuffing out.”
Van Zyl is part of the BirdLife South Africa Taita Falcon Survey Team, which operates under the auspices of BirdLife South Africa. The survey team is recognised as the global species guardian for the Taita falcon by BirdLife International’s preventing extinctions programme.
The organisation estimates there are fewer than 500 pairs of Taita falcons left, which are sparsely found in sub-Saharan Africa, specifically scattered from Ethiopia down to northern South Africa.
From the 1950s to the 1990s, the Batoka Gorge, in Zimbabwe, was the stronghold for the bird. In the mid-1990s at least six pairs were identified there. However, in the past decade there has been no sign of them. An intensive survey in 2013 and 2014 by Zimbabwean and South African scientists, including Van Zyl, failed to find any Taita falcons.
In 2018, a joint survey by the department of national parks and wildlife in Zambia and the Zimbabwe Parks and Wildlife Management Authority spotted one Taita falcon on three occasions in the Batoka Gorge.
“There’s potentially definitely something serious going on with the population of the Taita falcon,” Van Zyl said. “They’re dotted all over but these small little populations are all dying off, and nobody is really monitoring them, and they could suddenly disappear right under our noses.”
In South Africa, the cryptic falcon lives in the Blyde River Canyon area in Mpumalanga and Limpopo and favours rugged well-wooded areas. Its very specialised habitat requirements are thought to be among the reasons for its rarity.
In the mid-2000s, surveys in which scientists sat watching cliff faces for 12 hours a day with telescopes found an initial 11 Taita territories.
Since 2008, the population has been monitored annually but has shown a steady decline to only three occupied territories in 2022 and only one breeding pair last year, a reduction of more than 70%.
In 2010, the known population in South Africa was estimated at 20 adults, with the total unlikely to exceed 50. Nesting success has also plummeted — from a peak of nine fledglings in 2010 and 2015 to just two in 2020, an 80% decline.
Observing nests can take up to 12 hours a day in remote areas that are often only accessible by helicopter.
Recent scientific data and studies from the team suggest a substantial decline in breeding pairs in South Africa, with only a single pair known to have bred successfully last year.
“Originally, when we found them [the surveys started in 2008], there were 11 territories and we had eight active breeding pairs in those territories. They’ve been declining until now, where we’ve just got three active territories left in South Africa,” Van Zyl said.
“We obviously have been racking our brains to try and work out what is affecting them but because there’s so few around, and nobody has ever really studied them, it’s very difficult to work it out.”
The reasons for the precipitous decline remain unclear. Among the potential causes could be a lack of genetic viability, as there are too few birds; damage to the environment from extensive farming near the nesting sites; continued degradation of its woodland habitat and competition for prey and nesting sites from other falcon species.
This is particularly the case with the larger Lanner falcon, which has usurped some of the Taita falcon’s nesting sites in the Mpumalanga area. Alternatively, the population might have declined past a critical tipping point, leaving it so vulnerable that even minor disruptions could trigger catastrophic losses.
“We really want to find out what’s affecting them first before we can come up with a conservation strategy,” Van Zyl said.
“Especially since 2015, every year we seem to have lost some pairs. For instance, some of the pairs, we’ll go to check where they normally are and there would be for instance, a pair of Lanner falcons that are now nesting on the cliff and the Taitas are no longer there.”
At the end of last year, after the survey team scoured all the various territories, they only found three occupied territories. “Of those three, two of the cliffs only had single birds. There was one other cliff that had a pair on. In that sense, we’re down to only one pair in South Africa.
“For those birds who that are just single birds on the cliff, our understanding is that maybe they have lost their mate and, in a normal population, there will be a floating set of birds that are just moving around and then, basically, they will pair up with a single bird on a cliff and then they’ll be a pair again.
“But it could be the situation that, in our case, there are so few Taita falcons flying around that you could sit on a cliff for several years, hoping for a mate to arrive and nobody arrives.”
For this year’s survey, Van Zyl said the plan is to put a bigger team together to do a greater sweep of the canyon and the eastern escarpment area.
“We’ve got so few pairs at the moment that, even if we found another one or two pairs, that then almost doubles the known population here in South Africa.”
There is a glimmer of hope. In 2021, Van Zyl and his team recorded 14 breeding pairs in Mozambique’s Niassa Special Reserve, with estimates suggesting the region could host up to 70 pairs — the largest known population today.
“This has definitely put that area on the map. Fourteen pairs is not a lot but it’s the biggest population that we know of now. We’re wondering if that population partly supplies the Taita falcons to some of the other smaller populations that are around.”
However, Niassa has become increasingly inaccessible because of insurgent violence and instability, making conservation efforts difficult.
Without urgent research, protection, and habitat management, the Taita falcon could vanish, locally and regionally, within five to 10 years.