A third Black Harrier has been killed by the blades of wind turbines, on a wind farm situated between Bredasdorp and Swellendam. The Overberg Renosterveld Conservation Trust (ORCT) is now calling for additional mitigation measures to be tested at the wind farm, to find ways of protecting this threatened species.

Black Harriers are listed as globally Endangered (International Union for the Conservation of Nature) and only around 1 300 individuals remain today, with models indicating that annual declines are ongoing. Black Harriers are essentially endemic to South Africa, with a few birds popping into Namibia and Lesotho, where they may occasionally breed. However, the species’ breeding epicentre falls within the Fynbos Biome, extending into the Eastern Cape. Within the fynbos, they breed along the coast (in large reserves such as the West Coast National Park), and at relatively high altitudes in montane sites, while several important breeding sites are found in the Overberg’s remaining renosterveld patches, which lie scattered in a matrix of monoculture.

One of the most crucial breeding grounds is a large renosterveld fragment close to the Excelsior Wind Farm, owned and managed by Engie (previously BTE Renewables). In a concerted effort to prevent the deaths of threatened birds which are considered highly collision-prone, this wind farm has been implementing a shutdown-on-demand approach. This means that a team of nine observers are stationed at strategic points on the wind farm on a daily basis, constantly scanning for threatened species flying in the direction of the wind turbines. When they see a high-risk species approaching, they call, via radio to a control room, that the specific turbine(s) is shut down. This takes about 30-40 seconds so the call must be made early.

A success for larger threatened birds

According to Dr Odette Curtis-Scott, CEO of the ORCT, the approach has worked well for a number of threatened priority birds. She says, “This wind farm has been pioneering in adopting this practice to protect threatened species. They are the first wind farm to adopt the observer-led shutdown-on-demand approach in South Africa. And it seems to have worked well for larger threatened species, especially Cape Vultures and large eagles such as the Martial and Verreaux’s Eagle. There has not been a single recorded fatality among these species.”

However, the smaller, darker and often faster-flying Black Harrier has not been so lucky. A Black Harrier with a satellite tag (fitted by the ORCT) was killed late in 2021. The carcass of another Black Harrier that wasn’t tagged was also found below a turbine at the wind farm about a year later. “In this most recent devastating event, Peter, a Black Harrier that had a satellite tag fitted to him only in November 2023, was killed in February this year.”

According to Dr Rob Simmons, Harrier expert and a partner of the ORCT, “While Peter’s carcass wasn’t found, his satellite tag was found below the turbine, with damage indicating high impact. We only became aware that the tag was not moving four days after the collision had taken place, giving scavengers plenty of time to drag the carcass away or dispose of it.”

Scavenger removal is a common problem on wind farms and carcass searchers miss about one in every two carcasses due to removal (or inconspicuous victims). A study by Shaw and colleagues (2015) in the Karoo found that all carcasses are scavenged within a week, and six of the 15 had been displaced 20m or more.

Thus the number of dead Black Harriers could be double those found (i.e. at least six in this case since the wind farm came on line in 2020). Simmons says, “The real number is likely to be double the number of recorded fatalities, as unpublished carcass removal studies from a nearby wind farm has shown. For Black Harriers, wind turbines present a significant and relatively new threat. Given the existing pressures already on the population, which includes most importantly habitat loss and climate change, the species cannot afford to be further compromised at all. Population modelling undertaken by the University of Cape Town shows us that they could become extinct in the next 75 to 100 years if just three to five additional individuals are killed annually.”

An opportunity to test blade patterning

Curtis-Scott says there are more mitigation steps that can be taken by wind farms across South Africa. “While this is a loss for the already threatened Black Harrier population, there is an opportunity to use these new data on wind turbine collisions and turn it into a positive. For example, there is growing evidence that blade painting could reduce collisions with turbines, with birds able to pick out the movement of the turbines better when one turbine is painted with a high-contrast colour. While we still need considerable research in this field, this could be an excellent opportunity to test this mitigation method. A recent and exciting ‘win’ for the conservation community was the approval of blade patterning by the Civil Aviation Authority, all due to extensive negotiation and motivation put forward by Dr Simmons and our colleagues at the South African Wind Energy Association (SAWEA) and BirdLife South Africa.”

The Overberg Renosterveld Conservation Trust is undertaking a research and conservation programme for renosterveld-breeding Black Harriers – a flagship species for renosterveld and fynbos conservation. Black Harriers are dependent on intact and healthy renosterveld for breeding purposes. The team, with wonderful support from donors and partners, have GPS-tagged 15 Black Harriers to date. With four tagged birds confirmed to have died (two from wind turbine collisions, one at the hands of a grain cutter and one likely via natural predation), there are still 10 satellite tags that are providing data to the team.

Curtis-Scott says, “We recently joined forces with colleagues Dr Megan Murgatroyd and Prof Arjun Amar, who are also currently tagging Black Harriers, which will mean that our collective sample of tagged harriers will effectively be double what it would have been without this collaboration. The information we are collecting through these GPS tags is phenomenal. We can better understand movements and habits of the birds and can increasingly see the many threats that Black Harriers face. We would never have been able to find out about mortalities and their causes without these tags.

“With this information, conservation organisations across South Africa will be able to implement conservation measures to protect these charismatic birds, and to work to secure a future for a species that otherwise could become extinct in the not-too-distant future. We are pleading with all wind farms that are impacting, or could impact on threatened birds, to consider implementing, or in the very least testing, the various tiers of mitigation, particularly the blade-patterning option.”

Southern Black Korhaan may perhaps not have the flair associated with the striking Black Harrier. Still, protecting the species, a seemingly clumsy and often-noisy bird, is just as important to the Overberg Renosterveld Conservation Trust (ORCT), at a time when the species truly needs a helping hand.

The species was uplisted to Vulnerable on the red list several years ago, after a PhD study about 13 years ago by Sally Hofmeyr noted significant declines in population numbers. Given the fact that Southern Black Korhaan breeds in renosterveld habitats (amongst others), it has been a top priority for the ORCT. However, attempts to survey for the species and kick-start some research projects in 2021 and 2022 were not very successful, given the species’ extremely shy and secretive nature, making it a very difficult subject for field studies.

Above: Southern Black Korhaan. Image: Odette Curtis-Scott

Thus, as a first step, we reached out to partners to get a grip on current population estimates and trends.

With funding support from WWF South Africa, the ORCT has partnered with the Nuwejaars Wetlands Special Management Area and BirdLife South Africa to firstly better understand the threats to Southern Black Korhaan (Afrotis afra), and then to find ways to protect the species.

So the ORCT and partners called in the help of the experts. Ornithologist David Allan was on hand to undertake a review of the species, in order to identify population trends and conservation needs.

A major reduction in abundance

In his report, called ‘Out of the black and into the red: Review of the status of the Southern Black Korhaan’, he confirmed that available data reflects a major reduction of abundance in the Southern Black Korhaan (SBK). “This decrease was particularly rapid during the period corresponding with about 1993-2006 and slowed after this except in the Swartland area where there has been a continuous substantial decrease, possibly to the point of near local disappearance.”

Above: Comparison of the distribution and relative abundance of the Southern Black Korhaan from SABAP1 (1982-1992, left) and 2 (2007-2023, right). The darker blue shading in the cells represents higher reporting rates and hence relative abundance.

Allan compared the Southern African Bird Atlas (SABAP) 2 data versus that of SABAP 1. The SABAP 1 data were collected between 1982 and 1992; while the SABAP 2 data spanned the 16-year period, from 2007-2023. Allan says that from the data it is immediately clear that although the Southern Black Korhaan distribution range was largely unchanged between the two periods, a marked reduction in relative abundance was noted. “This reduction in abundance appears particularly severe in the central parts of the range, suggesting the decrease is most pronounced in the Fynbos Biome.”

From the Coordinated Road Count data (or CAR counts), an initial sharp decrease is noted in the Overberg from 1998 to 2009, but this subsequently levels off, a trend that persists to the present day. Allan says, “There is certainly no evidence of any sustained recovery from the position at the end of Hofmeyr’s examination in 2010.” However, he does raise some questions as to the consistency of the CAR data, which may have been impacted by the Covid lockdowns and other factors.

Above: Southern Black Korhaan. Image: David Allan

Habitat loss is the biggest concern

The major threat to Southern Black Korhaan is identified in the report as habitat loss and fragmentation – especially the loss of fynbos and renosterveld. He says, “Cultivation, both irrigated and dryland, is the primary driver of this habitat loss, although other land-uses have doubtless also impinged on SBK habitat, e.g. human settlement. Farming activities associated with cultivation also carry with them increased human disturbance, perhaps particularly problematic relevant to SBK breeding activities.”

What’s more, climate change is likely to further impact on the already fragmented and degraded Fynbos Biome, particularly in the lowland areas inhabited by the Korhaan – including renosterveld. And some collisions with wind-turbine blades were also recorded – a threat that is likely to increase as more wind farms are erected.

While these findings are instrumental to highlight the current state of Southern Black Korhaan, they are only seen as the starting point. Allan makes a number of recommendations – including establishing a working group to focus on SBK conservation and developing a Biodiversity Management Plan for SBK at national government level.

Above: Southern Black Korhaan. Image: Odette Curtis-Scott

There are about 130 reasons to come birding in the renosterveld of the Haarwegskloof Reserve. This renosterveld reserve, situated between Bredasdorp and Swellendam in the Overberg, offers the largest intact stretch of renosterveld left on Earth. And that makes it a favourite for many bird species that rely on this natural vegetation, part of the Cape Floral Kingdom, to breed and feed.

Above: Malachite Sunbird

To date, CEO of the Overberg Renosterveld Conservation Trust (ORCT) Odette Curtis-Scott, Conservation Manager Grant Forbes (both birders) and the rest of the team have tallied up a total of more than 130 bird species on the reserve. But interesting and unusual birds are often seen passing through the reserve, and so that list is constantly growing.

Odette says, “We’ve made it a fun challenge for our conservation team, and for the birders who visit this reserve to try and help us increase the number. Most recently we added Jacobin Cuckoo to the list – which was an exciting addition. And last year we were thrilled to see Western Osprey heading over during our Birding Big Day count.”

For birders, here are the top five incentives to come and bird in this area.

Your gold prize sighting: Black Harrier

The Endangered Black Harrier has become the flagship birding species for renosterveld conservation. Because it relies on these intact natural patches to lay its eggs and raise its young, the ORCT has launched a project to protect Black Harriers, by understanding them better. Fifteen renosterveld-breeding Black Harriers were tagged with GPS tracking devices, to monitor their movements.

Odette says, “When we see Black Harrier, we always consider it a privilege: There are only 1300 mature individuals left on the planet, and this enigmatic raptor is facing extinction. So for us, seeing them hunt over renosterveld is one of our favourite birding moments.”

Above: Endangered Black Harrier

The soaring scavengers passing over: Cape Vulture

The Haarwegskloof Renosterveld Reserve is perfectly situated between the Potberg colony of Cape Vultures, and some of their scavenging grounds in the Overberg. So watching these majestic birds soar overhead in the morning, while enjoying a morning coffee on the stoep of the guest accommodation is a sight to behold.

Grant, who has lived on Haarwegskloof, says, “We sometimes see groups of 10-20 vultures cruising over the reserve. We are so grateful to the farmers who leave carcasses out for them, so that they still have a reliable food source in this heavily transformed landscape.”

Above: Cape Vulture

Spot the covert Korhaans: Southern Black Korhaan and Karoo Korhaan

For the ORCT, while both species are threatened and therefore special, the Southern Black Korhaan in particular is a wonderful sighting, as they are far more dependent on the natural remnants than their cousins which seem to spend most of their time in the farmlands. These birds are very secretive, and you’ll usually see them as they sneak into a patch of natural bush, or squawking loudly as they fly away.

Odette says, “We know from SABAP (South African Bird Atlas Project) data that numbers of Southern Black Korhaan have decreased in recent years. We’re reaching out to partners to collaborate on understanding these declines so that we know what conservation actions are needed to protect them.” 

Above: Southern Black Korhaan

The leading LBJs: Don’t miss this essential endemic

The Haarwegskloof Renosterveld Reserve is home to many Little Brown Jobs. The fun Cape Clapper Lark is frequently seen ‘clapping’ his wings above renosterveld, before diving down. Red-capped Lark and Large-billed Lark are also all easily spotted during a renosterveld stroll or a drive around the surrounding farmlands. But the standout LBJ is undoubted the Agulhas Long-billed Lark – one of the few bird species that is endemic to the Western Cape, only occurring around the most southerly tip of Africa. As a result, it’s listed as Near Threatened.

Grant says, “Until recently, very little was known about these larks. However, recent research by Sanjo Rose, which included the larks breeding on our Haarwegskloof Renosterveld Reserve, provided essential info on them, and highlighted how important renosterveld is to their survival. The research also shows that nest failure was particularly high, with only four broods successful from 29 nests.”

Top: Cape Clapper Lark. Bottom: Agulhas Long-billed Lark

Varying vagrants who visit the reserve

Over the years, the conservation team has identified a number of interesting migrants and vagrants stopping off to rest and recuperate in the renosterveld, before heading off. Pretty migrant visitors include European Bee-eater, Lesser Kestrel and Jacobin Cuckoo.

• Some bird species are threatened by the loss of Renosterveld (think: the Black Harrier).
• Some prefer a transformed landscape (like the Blue Crane).
• And others, it seems, don’t seem too fussed either way – like the Agulhas Long-billed Lark.

A new study surprised researchers and experts, finding that this Overberg endemic Lark (Certhilauda brevirostris) is not too concerned about the vegetation cover or habitat type – as long as the vegetation is short.

That’s good news for the Agulhas Long-billed Lark, especially in the Overberg, where much of the landscape has been transformed for agricultural purposes. The Lark is listed as regionally Near Threatened by BirdLife South Africa.

The study was undertaken by Oxford University’s Celeste de Kock and Dr Alan Lee of the FitzPatrick Institute of African Ornithology. It was recently published in African Zoology.

Much of the research was conducted around our Haarwegskloof Renosterveld Reserve – where you’ll find a mix of agricultural landscapes and Renosterveld patches. Celeste also visited the Nuwejaars Wetlands Special Management Area as part of the study.

Her research found that the Agulhas Long-billed Lark prefers vegetation generally shorter than 30cm – including agricultural lands. These transformed lands seem to have no negative impact on the birds.

But she says, “(I)t is difficult to draw firm conclusions from the current study whether agriculture is beneficial to Agulhas Long-billed Larks or not. Because vegetation height is the only predictor of bird occurrence, it could well be that current agricultural practices might be mimicking historical ecological processes, i.e. the creation of open areas after fires…”

She recommends more studies on the reproductive output and movements of the Lark.

Here’s what her study found:

• A total population of between 203,000 and 368,000 individuals is estimated;
• Birds are usually on their own, or in pairs (but seldom 3 or more together);
• There’s no evidence that numbers are declining.
• In her view, the more appropriate Red Data List status would therefore be ‘Least Concern’, implying that the birds’ status is less of a concern than originally thought.

Still, some threats remain to the Larks.

The extensive road network in the region is a worry – with the reporting rate for these birds lower for areas with extensive road access. “This might suggest that Agulhas Long-billed Larks will not adapt well to intensive development,” she says.

While this is good news for the Agulhas Long-billed Lark, the ORCT continues to focus on healthy, well-managed remnants and corridors of natural veld through its Easement Programme – to support other endemic and threatened bird species.

The project is supported by WWF South Africa, and is being implemented across the Overberg Wheat-belt.