Three lions died this week in southwestern Kenya after eating a poison-laced cow carcass, Wildlife Watch reported. Those lions, and five others also poisoned, come from Masai Mara National Reserve’s Marsh Pride, which starred in the popular BBC series called Big Cat Diary.

The lions might be the best known victims of this incident, but they’re not the only ones. Eleven endangered white-backed vultures also died after feasting on poisoned carcasses—and these deaths underscore a huge problem. In Africa and elsewhere, poison has contributed to the population decline of these scavengers, whose importance is often overlooked because of their perceived ick factor.

“Across the board, it’s the biggest threat worldwide,” says Darcy Ogada, assistant director of African