The Lyall’s Wren Lie: Why it’s Dangerous for Cats

Maybe you’ve heard this story before. A lighthouse keeper named David Lyall brought his cat, Tibbles, when he moved to the remote Stephen’s Island (New Zealand). Within one year of Tibbles’ arrival, a flightless bird native and exclusive to the island went extinct. 
Tibbles was known to have hunted the bird, now known as the Lyall’s wren, and the alignment of its disappearance with her presence on the island fostered the myth, referenced still by some people today, that a single cat quickly wiped out an entire species.

Here are the facts:

•    Tibbles was pregnant when she came to Stephens Island. Therefore, her kittens would have contributed to the hunting of the Lyall’s wren, of course. When one considers that some female cats are able to breed by just four months of age and have up to three litters per year, it becomes obvious that one litter of kittens (even a small litter) would multiply many times over.
•    Cats would not have existed on Stephens Island, any other island, or most places on this planet, if people had not brought them there and failed to take measures to control the cats' breeding. Since all of the cats on Stephens Island came from one litter, Tibbles and her offspring clearly interbred, which probably led to all sorts of health conditions for the cats. The cats here were as much victims of poor human judgement as the wrens.
•    The Lyall’s wren is one of only two species whose extinction can reliably be traced to cats, despite some conservationists’ wild claim that cats are responsible for hundreds of extinctions. The circumstances that allowed for the Lyall’s wren extinction were clearly unusual and unlikely to reoccur. In fact, outside of the unique ecosystems of a remote island like Stephens Island, there is actually no proof that cats have a major effect on prey species populations.