Black and turkey vultures cause problems in several ways. The most common problems associated with vultures are structural damage, loss of aesthetic value and property use related to offensive odors and appearance, depredation to livestock and pets, and air traffic safety. Management of these diverse problems often can be addressed by targeting the source of the birds causing the problem, namely the roost where the birds spend the night. Often the roost itself is the problem, such as when birds roost on a communication tower and foul the equipment with their feces or when they roost in a residential area. Several methods are available for roost dispersal. Vultures are protected by the Migratory Bird Treaty Act, and are managed by the federal government. Vultures may be harassed without federal permits, but can be killed only after obtaining a Migratory Bird Depredation Permit from the U.S. Fish and Wildlife Service. State wildlife agencies may require state permits prior to killing migratory birds.