Over 800 birds killed after colliding with turbines during four year period-study

Over 800 birds were killed after colliding with turbines at 20 wind energy facilities (WEFs) in South Africa between 2014 and 2018, a new study has revealed.

The toll includes species of conservation concern such as endangered Cape Vultures and Black Harriers, both endemic to southern Africa.

The paper, On a collision course? The large diversity of birds killed by wind turbines in South Africa was published in Ostrich, the journal of African Ornithology, last week by the Fitzpatrick Institute of African Ornithology at UCT and BirdLife South Africa.

The carcasses of 848 birds were recovered, with this figure a crude rate based on the number of carcasses found beneath the turbines, explains study author, Sam Ralston-Paton, birds and renewable energy project manager at BirdLife SA.

"This will be an underestimate of the actual number of fatalities as scavengers may have removed carcasses or they might have been overlooked by the searchers or otherwise not recorded."

A "striking result" was the high diversity of birds killed: 130 species from 46 families, totalling 30% of bird species recorded at and around WEFs, including some not recorded by specialist surveys, like flufftails.

Most carcasses were raptors (36%; of which 2% were owls), passerines (30%), waterbirds (11%, of which 3% were waterfowl), swifts (9%), large terrestrial species (5%), pigeons and doves (4%) and other near-passerines. Of the 130 species recorded killed, 16 were migrants.

Wind energy is a clean, renewable alternative to fossil fuel-derived energy sources but many birds are at risk from collisions with wind turbines, write the authors.

SA has the greatest installed wind energy generating capacity on the continent, with the number of operational turbines rising from 253 in 2014 to 825 in 2017.

The study is the first to provide a comprehensive summary of the range of birds impacted by turbine collisions at a national scale in the southern hemisphere.

Raptors were the group most frequently found dead, "confirming their susceptibility to turbine collisions". The Jackal Buzzard was the species most often killed. With a population estimated in the tens of thousands, "population level impacts may not be significant ... but continued monitoring and additional research is recommended to help ensure this common species remains common and the ecological implications of any losses are understood."

The abundant Amur Falcon was the migrant species most often killed while the endangered Cape Vulture is the species of greatest concern, "especially because the closely-related Griffon Vulture suffers very high mortality rates at WEFs in Spain".

Ten Cape Vulture collision fatalities have already been reported "despite this species’ small population and its limited spatial overlap with existing WEFs.

"Given the short monitoring period in our study, we anticipate more Cape Vulture fatalities in future and this could become a very serious concern if additional WEFs are constructed in the vulture’s core distribution. Without careful planning, other vulture species also are likely to be impacted as WEFs are built throughout Africa, further contributing to the continent’s vulture ‘crisis’."

With a total population of only 500 -1 000 breeding pairs, six endangered Black Harriers have been killed at local sites. "If this trend continues, wind energy facilities could pose a significant threat to the survival of the species."

Verreaux’s Eagles, too, appear to be particularly susceptible, with four birds killed at one wind farm in three months and two fatalities at different WEFs. Four nationally endangered Martial Eagles were killed as well as 21 other eagles from four species.

"Every effort must be made to site wind energy facilities away from important areas for birds, particularly raptors. Species at risk should become a key focus of environmental impact assessments and strategic environmental assessments, which are important tools to reduce the impacts of wind energy developments."