Reports of black vulture predation on young livestock in the Midwest have been on the rise as the birds expand their range. The situation has prompted a growing numbers of permits from the U.S. Fish and Wildlife Service to take birds that are threatening calves. But questions remain about how severe the problem is. Some researchers question the validity of claims, saying there is a lack of data on confirmed cases of black vultures (Coragyps atratus) attacking healthy livestock. “I am going to take an extreme position here and say they don’t kill healthy calves,” John W. Fitzpatrick, the recently retired director of the Cornell Lab of Ornithology, told the New York Times. He and others suggest a more cautious approach until more is known about how pervasive the issue really is.