Overrun by a rapidly expanding bison herds, California's Catalina Island is taking a revolutionary approach to population control: Bovine birth control. Whereas traditional methods for reducing overpopulated herds have including controlled hunting, killing, or shipping strategies, Catalina Island Conservancy—a nonprofit that owns 88 percent of the island—is pioneering a non-hormonal birth control shot for female bison. "Males will continue to compete for females, and females will continue to go into heat. The only difference is that we can control how many calves they have," explains the conservancy's chief. "For bison in love, this means romance without responsibilities." For the sake of eco-sustainability, the conservancy aims to quell the herd's current annual growth rate of 15 percent.