Wildlife & Biodiversity

African raptor population declines 88% in 40 years, many crossing IUCN threshold: Report

Evidence indicates two-thirds of 42 examined species to be globally threatened  

By Himanshu Nitnaware
Published: Sunday 07 January 2024
Photo: iStock

Raptors in Africa have experienced a widespread decline of about 88 per cent in the past 40 years, a new study revealed.

Scientists said that 37 of the 42 species examined by them have seen a decline in their population. Out of the total, 29 (69 per cent) have seen a drop in population over three generation lengths. The generation length criteria is used by the International Union for Conservation of Nature (IUCN) to identify species which are at the risk of global extinction. 

Two-third of the studied population from 1969-1995 and 2000-2020 across Africa show strong evidence to be globally threatened.

The researchers studying 27 species in multiple regions of Africa found that 24 of them (89 per cent) exceeded the decline threshold. As many as 13 of these species are enlisted in the Least Concern category, raising the issue of reassessing their status. Six of the species that is secretarybird (Sagittarius serpentarius), lappet-faced vulture (Torgos tracheliotos), bateleur, tawny eagle (Aquila rapax), steppe eagle (A nipalensis) and martial eagle (Polemaetus bellicosus) are endemic or near endemic to Africa who have declined rapidly than the threshold rates, a method used by IUCN to define threat status.

“Three additional species showing steep declines are augur buzzard (Buteo augur), Dickinson’s kestrel (Falco dickinsoni) and Beaudouin’s snake-eagle (Circaetus beaudouini). The latter is of particular concern, having declined by 80-85 per cent over three generation lengths within a large (and probably representative) portion of its global breeding range,” the study noted. 

The findings published in the journal Nature Ecology & Evolution states that the raptors are seeing rapid decline in population owing to loss of habitat, loss of prey-base and anthropogenic disturbances. 

The study stated that the human population in the continent has increased rapidly over the past 60 years leading to high expansion of land conversion and habitat degradation, threatening the raptors. 

It noted that annually, nearly five million hectares of forest and non-forest natural vegetation was lost in sub-Saharan Africa. The declines were more prominent in West Africa where the situation was worse than sub-Saharan Africa.

Corruption, regional levels of poverty, lack of funding and mismanagement led to adverse effects on conservation of species in protected areas of west and central Africa.

Moreover, the rate of agricultural expansion was recorded to be three time more in the West Africa compared with the rest of Africa between 1970s and 2000s. 

The combined effect has resulted birds of prey increasingly relying on Protected Areas (PA), which amount to 14 per cent of the land.

The study warns that if the trend continues, the pressure on PAs will increased. 

However, it noted that birds in PAs were also at risk. “While annual declines on unprotected land were thus often substantially higher than within the PAs we assessed, there is now widespread acknowledgement that many African PAs are also losing their ecological integrity, thereby depriving threatened species of effective refugia,” it said.

Apart from loss of habitat other threats of concern to the avian apex predators, scavengers and miso-predators include prey-base depletion, unintentional poisoning, killing by poisoning, shooting, trapping, electrocution and collisions with human built energy infrastructure, according to the researchers. 

They said that raptors which breed slow also face difficult in recovering the rapidly lost population.

It observed that depletion in predator population can trigger cascading effects on its prey populations and disrupt the ecosystem functioning. Raptors provide crucial ecosystem services such as rapid removal of carcasses through consumption and decreasing the risks of spread of zoonotic diseases to human populations.

The researchers noted that the analysis of African raptors seeing stepper annual declines compared to smaller species reflect pattern of extinction risks observed similar to terrestrial mammalian predators. 

The risks to large bodied species multiply due to biological traits such as low population density, low annual fecundity and delayed maturity. 

The authors said that plight of these African species, especially the endemic indicate the pressing need for research on ratios with restricted breeding ranges.

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