In Mandurah, Australia, biologists created a bird sanctuary to attract a vulnerable and cartoonishly adorable native seabird called the fairy tern. Fairy terns don’t usually nest near people, but to the city’s great pride and joy, they did start having chicks in Mandurah. It was a success story—until it wasn’t.

Victims were soon found dead—“decapitated” and “breasts opened”. The killer turned out to be a white cat who single-handedly drove off the entire bird colony, turning the sanctuary from a success to a failure.

Although cats like to roam freely, cats do tend to kill birds so there’s a huge tradeoff in giving cats freedom and watching birds get killed. If you’re going to let your cat outside, put a bell around its neck or somehow alert birds to the cat’s presence. That way birds and cats can both thrive outside.

To learn more about the bird sanctuary killer, click here.