Africa’s birds of prey declining due to habitat loss
These scavengers, which take long periods to breed, are at risk as their natural habitats are converted to farmlands to cater for the steadily increasing human population.
What you need to know:
- These scavengers, which take long periods to breed, are at risk as their natural habitats are converted to farmlands to cater for the steadily increasing human population.
- Due to habitat loss, their prey has also reduced, threatening their survival.
The population of African savanna raptors, members of the continent’s birds of prey, is steadily declining because of habitat loss. Ninety per cent of the bird’s 42 examined species are on the decline, with more than two-thirds possibly qualifying as globally threatened.
These scavengers, which take long periods to breed, are at risk as their natural habitats are converted to farmlands to cater for the steadily increasing human population. Due to habitat loss, their prey has also reduced, threatening their survival.
Besides, the birds also face persecution from loss of breeding sites, persecution from pastoralists and farmers, unintentional poisoning, killing for food and electrocution on power lines.
This is according to a study published on January 4 on the journal Nature Ecology and Evolution by researchers from the School of Biology at the University of St Andrews and The Peregrine Fund.
The study titled ‘African Savanna Raptors’ shows evidence of widespread population collapse and a growing dependence on protected areas. It utilises data from road surveys across four African regions conducted every 20–40 years.
The study exposes that larger raptor species are undergoing more substantial declines than their smaller counterparts, especially on unprotected land where they face heightened vulnerability to persecution and other human pressures. The overall decline of raptors is more than twice as rapid outside of national parks, reserves and other protected areas compared to within. Alarmingly, species experiencing the sharpest declines are doubly at risk, having increasingly relied on protected areas during the study.
The authors warn that unless the numerous threats confronting African raptors are effectively addressed, the existence of large, charismatic eagle and vulture species across much of the continent’s unprotected land is uncertain by the latter half of this century.
Additionally, the study sheds light on steep declines among raptors currently deemed “least concern” in the global Red List of threatened species. This group includes African endemics like Wahlberg’s Eagle, African Hawk-eagle, Long-crested Eagle, African Harrier-hawk, Brown Snake-eagle, and Dark Chanting-goshawk. The observed decline rates suggest that these species may now be globally threatened.
“Since the 1970s, extensive areas of forest and savanna have been converted into farmland, while other pressures affecting African raptors have likewise intensified. With the human population projected to double in the next 35 years, the need to extend Africa’s protected area network—and mitigate pressures in unprotected areas—is now greater than ever,” said Dr Phil Shaw, the study’s lead author.
“Africa is at a crossroads in terms of saving its magnificent birds of prey. In many areas we have watched these species nearly disappear. One of Africa’s most iconic raptors, the Secretary bird, is on the brink of extinction. There’s no single threat imperilling these birds, it’s a combination of many human-caused ones, in other words we are seeing deaths from a thousand cuts,” said Dr Darcy Ogada, the study’s co-author.
A previous study published on ScienceDirect shows that the population of 19 out of 22 species of these birds has been on a steady decline for over 40 years due to rapid human population growth. The numbers have fallen by more than 50 per cent.
The study also blames development of roads, railways and energy infrastructure, which has fragmented habitats, large-scale, chemically-intensive farming, unplanned development polluting water sources and widespread deforestation, which has reduced water levels and intensified soil erosion.
“A sharp increase in livestock numbers in recent decades has led to overgrazing, reducing grass cover and small mammal populations and, by extension, diminishing the prey base for raptors. The result is a biologically impoverished landscape that is less resilient to climatic changes and provides fewer ecosystem services, and where attitudes toward wildlife have become increasingly intolerant,” says the study.
“Of Kenya’s 102 raptor species, 14 per cent are globally threatened (BirdLife International, 2020) and six of the country’s eight vulture species are classified as Critically Endangered or Endangered, reflecting Pan-African vulture declines averaging 62 per cent over the past 30 years,” says the study.
“Among the biggest threats to raptors globally are habitat destruction through logging and agricultural expansion, persecution (such as shooting, poisoning and trapping), electrocution and collision with energy infrastructure, contamination (primarily from lead, pesticides or veterinary drugs), and illegal harvesting for belief-based use,” adds the study.
“Our findings underline the urgent need to strengthen the protection of Kenya’s birds, reduce specific threats to raptors, and develop a National Red List for all species. While Kenya’s raptor declines have been ongoing for at least four decades, no concerted national effort has been made to conserve these top predators.”
According to Endangered Wildlife Trust, African raptors are critical in maintaining a healthy ecosystem, by cleaning up carcasses, reducing spread of diseases, hunting rodents and other creatures that can negatively impact human health. Results of blood tests from raptors can also be used to indicate the health of an ecosystem.
