CAPE TOWN — More than 530 endangered vultures have been killed in northern Botswana after ingesting poison left by elephant poachers, the government said on Thursday, underscoring the broader ecological fallout from Africa’s illegal trade in ivory.

Five vulture species were identified at the site, which lies near Botswana’s border with Zimbabwe. Conservationists said that poachers had poisoned the birds in an effort to evade detection. As scavengers, vultures are attracted to freshly killed animals, and their presence in the air can alert rangers to poachers’ positions.

“Vultures are sentinels to poached animals, so they’re directly being targeted,” said Kerri Wolter, the founder and manager of VulPro, a nonprofit conservation group based in South Africa.

Poaching appears to be on the rise in Botswana, which is home to around one third of Africa’s elephant population and has long been regarded as a safe haven for the animals. A recent study estimated that over 385 elephants had been poached from 2017 to 2018, a lower total than in other parts of Africa but an alarming rise for Botswana, the scientists said.