Bison birth control discussed

(CNN) - While most communities in California are turning to hunting and killing to control pesky bison populations, scientists in one community are taking a different approach: Birth control.

Many of the hundred of thousands of tourists each year who make the short trip to Catalina Island are drawn by the chance to see a bison in the wild. But in recent years, bison overpopulation has threatened the island's eco-system.

Fourteen bison were originally brought to Catalina Island in the 1920s for a movie shoot. By the 1960s, they had multiplied to 600.

The conservancy that operates most of the island has tried auctioning the animals to ranchers, and even shipping some back to Native American reservations in South Dakota. However, birth control would be a much more humane, cost-effective experiment.

"We are trying to find a balance between ecological, cultural, social and economic values," Ann Muscat, President of the Catalina Island Conservancy. "We could keep a small number of animals on the island, we could continue to monitor their impacts and manage for their impacts on the environment, but they would still be here for people to enjoy."

Scientists, animal rights activists, conservancy workers and volunteers helped lure Catalina's bison into pens. Females were then injected with an animal contraceptive called PZP, which has never been tried on bison in the wild.

The hope is it will reduce births by about 90 percent by thickening the walls of female bison eggs. The injections are expected ot have no impact on bison behavior, while eliminating the need for expensive and potentially harmful relocation. It may take two years to determine whether the plan will work, but seeing it in action brought one long-time animal activist to tears.

"I would like to thank the Catalina Island Conservancy for taking this unique step that will save the lives..." said Bill Dyer with In Defense of Animals.

The Catalina bison were then rereleased to roam the island, and remain living tourist attractions, as well as links to America's past.