The Catalina Island Conservancy, an animal rights group and a number of veterinarians and wildlife biologists put their collective heads together to come up with this non-lethal solution to control the herds' numbers.
"With the permission of the conservancy, we relocated 103 bison to Indian reservations in South Dakota. Additional bison were relocated twice more in recent years. During these episodes, we discussed the possibility of contraception with the conservancy to avoid the difficulty and expense of constantly relocating the island's bison and to prevent the stress it caused the animals," said Bill Dyer of In Defense of Animals.
Bison were first introduced to Catalina back in the 1920 in the silent-film era. They're grass eaters, just like many other animals on the island. Using this birth control method was the best way to control the bison population.
"It doesn't alter their behavior. Males and females will still mate with each other; they just won't give birth to calves. It is affordable. It is not something that works its way through the food chain," said Dr. Ann Muscat of the Catalina Island Conservancy.
At its peak, the Catalina Island's bison herd numbered about 600. Currently, the population is at about 150, and that's where the conservancy would like to keep it.
"They've become iconic animals of the island, and people that live here and people that come to visit really love them, and so we're trying to look for that balance, and a way to accommodate a diverse group of opinions and ideas," said Muscat.
The vaccine will be given yearly. It is reversible, though, so if the conservancy wants to increase the bison population, it can.