With their creepy appearance and diet of dead animals, vultures get a bad rap. But the scavenging birds play a critical role in the ecosystem. By eating dead animals, vultures are “cleaning up the environment and helping to prevent the spread of disease,” says Evan Buechley, a biologist at the University of Utah.

Unfortunately, these crucial birds are in decline. Vultures often consume animal carcasses that humans have accidentally poisoned with toxins. In the U.S., lead bullets used for hunting can contaminate a vulture’s meal. And in South Asia, vulture populations dropped more than 90 percent in 10 years because the birds were eating cows given medicine that hurt them.

There’s hope for vultures, though. India, Pakistan, and other countries have banned the medicine harming the birds. And scientists like Buechley are working to raise awareness and help vulture populations elsewhere. “As vultures decline, nothing else can really replace them [in the ecosystem],” says Buechley.