Birds of prey in South Africa are in trouble – a study analyses data from 16 years of road counts

Birds of prey and vultures (raptors) play a vital role in ecosystems, both as top predators and key scavengers. However, compared to many other bird species, raptor populations are declining faster. This is because they need large areas to live in, have low population densities, and reproduce slowly. For these reasons they are vulnerable to human impacts like farming with pesticides, electrocution, collision with wind turbines, or poaching.

In many cases, by the time scientists and conservationists fully understand how bad the declines are, it may be too late to act. Thus, having good population monitoring is vital to act as an early warning system of declines. Many countries in the global south host important populations of raptors but lack effective monitoring programmes.

Africa is an important continent for raptor diversity. Several studies across Africa have used road counts (counting birds from repeated transects across routes) to monitor how raptor populations have changed over time. A recent study went one step further, combining trends from these different surveys from across Africa to better understand these changes at a pan-African scale. Unfortunately, no data from South Africa were available to be incorporated into this analysis.

In our recent study we took advantage of data that was collected by one dedicated fieldworker, Ronelle Visagie, who drove nearly 400,000 km (the distance from Earth to the moon) across the central area of South Africa (see map) between 2009 and 2025, while she worked for the Birds of Prey Programme of the Endangered Wildlife Trust.

During these 16 years, Ronelle counted all the raptors and large birds that she saw on these work trips. Comparing how the rate of these observations (numbers of individuals per 100km driven) changed over time allowed us to explore species population trends. We had enough data to examine trends for 18 raptors and eight other large bird species over this period. Unfortunately, we did not find a good news story.

These road counts revealed that 50% of the species (13 out of 26) declined significantly, while only three species (12%) showed significant increases. The remaining ten species (38%) showed no significant trends (see Figure 2).

The declining trends raise serious concerns about the conservation status of several species in a region known to host important raptor populations. Thus, urgent conservation actions are needed, especially for species declining by more than 50%. Given that several of these species are not currently listed as threatened either globally or regionally, their conservation status may need to be reassessed.

Trends in raptor populations

According to our results, 42% of the assessed species declined by more than 50% in the last 16 years.

Notable declines included all of the three migratory species assessed (lesser kestrel, amur falcon and steppe buzzard). These trends match other studies from their breeding grounds in the northern hemisphere, which also suggested declines. Protecting migratory species is especially challenging because action may be needed in breeding areas, non-breeding areas, and along migration routes, where the threats they face may differ.

We also found declines of several resident raptors, including jackal buzzard, Verreaux's eagle and secretarybird. Populations of these species declined by over 50% in our study region.

In contrast, populations of white-necked raven, greater kestrels, and white-backed vulture increased. The latter is a critically endangered species, but seems to be increasing within our study area.

Some of the trends we detected were similar to a recent study that explored raptor population trends from across Africa using similar approaches to our study. For example, our findings of large declines for secretarybird and lesser kestrel were very similar to those reported in Kenya and Botswana. Additionally, similar population changes for secretarybird were detected during winter (but not summer) using road counts in the Nama Karoo (a major part of our study area) during the period just before our study (a 61% decline between the late 1980s and early 2010s). This suggests that the decline detected earlier may have continued into the mid-2020s.

We compared the direction of trends (whether species numbers were going up or down) from our road counts and the Southern African Bird Atlas Project (SABAP2). But only about half of the trends agreed between the two methods (road counts and the bird atlas). Species with consistent trends between the methods included amur falcon and lesser kestrel – both showing declines – and greater kestrel and white-backed vulture – both showing increases. Species with inconsistent trends all showed decreases according to our road counts but increases according to the bird atlas project. These included Ludwig's bustard, blue crane, secretarybird, black-winged kite, and southern pale chanting goshawk.

If we assume that our road counts trends are reliable, these findings suggest that although the bird atlas project data can provide valuable information on the changes in distribution of birds, atlas data may be less well suited to capture changes in abundance at large spatial scales and across multiple species.

Across Africa, declines in birds of prey are often linked to human population growth, agricultural expansion and climate change. In our study area, there have been no major recent changes in land use or population density, but more subtle or long-term human impacts may be driving these changes.

Conflicts between people and raptors, including illegal killings, could play a role. Climate change and infrastructure like power lines and wind farms are adding further pressure by fragmenting aerial habitat and affecting survival and reproduction.

Trends in human populations

Human populations in Africa are expected to grow significantly over the next three decades, which will increase pressure on biodiversity.

Given the projected human population growth in Africa (79%), and a corresponding rise in demand for resources and energy, threats to vulnerable bird species are likely to get worse.

It is therefore essential that we have reliable tools to monitor species trends and better understand the impacts of these pressures.

This is crucial for understanding the current biodiversity crisis and preventing severe wildlife loss.

Ronelle Visagie and Gareth Tate of the Endangered Wildlife Trust contributed to this research.

Santiago Zuluaga Castañeda received funding from The ABAX Foundation and a Juan de la Cierva postdoctoral contract from the Spanish government.

Arjun Amar receives funding from The ABAX Foundation.

Megan Murgatroyd does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

By Santiago Zuluaga Castañeda, JdlC Researcher, Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC) And

Arjun Amar, Associate Professor, FitzPatrick Institute of African Ornithology, University of Cape Town And

Megan Murgatroyd, Biologist, University of Cape Town

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