Cape Town — Authorities and conservationists have launched a probe after at least 40 endangered vultures have been killed in Botswana, the latest victims of mass poisoning in the Southern African country in months, reports Phys.org.

Vultures play a critical role in keeping ecosystems clean of diseases found in rotting carcasses, but in Africa, they are sometimes poisoned deliberately by poachers, or accidentally by farmers.

Vulture poisoning is not uncommon in wildlife-rich Botswana, but it's not clear whether this latest tragedy was accidental or a deliberate poisoning of the birds.

In June 2019, hundreds of mostly white-backed vultures were poisoned by poachers using elephant carcasses as bait. This may have been the largest mass poisoning of vultures in Southern Africa.

In 2013, 500 were poisoned in Zambezi under similar circumstances.

The numbers of vultures in Botswana has reduced drastically over the past years and they are on the verge of extinction.