Stephens Island is a tiny, windswept patch of land in the Cook Strait, wedged between New Zealand's North and South Islands, and for more than a century it has been remembered for one particular story, a cat supposedly wiping out an entire species of bird almost single handedly. The bird in question was Lyall's wren, a small, flightless songbird found nowhere else on earth, and the cat was Tibbles, brought to the island in 1894 by assistant lighthouse keeper David Lyall. According to popular legend, Tibbles alone hunted the wren into extinction within about a year of arriving, a tale so tidy and dramatic that it has been repeated in documentaries, quiz shows and nature books ever since. The real story, as researchers have since pieced together, turns out to be a good deal messier than the legend suggests.
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How the lighthouse on Stephens Island changed everything
Before 1894, Stephens Island had never seen a single mammalian predator, which is exactly why a flightless little bird like Lyall's wren had managed to survive there while similar species vanished from the rest of New Zealand centuries earlier. Construction of a lighthouse on the island began in 1892, and once it was completed, three keepers and their families, seventeen people in total, moved in to run it. David Lyall was one of these keepers and also a keen amateur naturalist, and it was his pregnant cat that arrived with him early in 1894, the very first cat ever to set paw on the island. Within months, Lyall began noticing dead birds being brought to his door, small creatures he did not recognise, with an olive brown body and a distinctive streak near the eye.
What David Lyall actually discovered
Lyall described the little bird as almost nocturnal, scurrying across the rocks so quickly that he could never manage to catch or strike one himself. He sent several of the preserved specimens off to prominent ornithologists of the time, including Walter Buller and Walter Rothschild, both of whom recognised it immediately as an entirely new species. The bird was eventually named Traversia lyalli in Lyall's honour, and it turned out to be one of the most unusual birds ever described, the only known flightless songbird in the world at that point in history. Sadly, by the time scientists had finished arguing over who got to formally publish its description first, reports were already suggesting the bird was gone from the island for good.
Why blaming a single cat is not the full picture
The popular version of events, that one cat named Tibbles single handedly exterminated the species within a single year, does not hold up well against the historical record. According to a detailed 2004 study published in the journal Notornis by researchers Ross Galbraith and Alan Brown, extinction of the wren actually stretched out over several years rather than happening in a single dramatic season, with specimens still being collected as late as 1899. The pair also found that Tibbles almost certainly was not working alone, since the cat gave birth to kittens soon after arriving on the island, and those kittens went on to breed further, quickly turning one pregnant cat into an entire feral population capable of hunting the island's birds far more effectively than any single animal could manage.
What official records say happened next
According to New Zealand Birds Online , a database maintained by New Zealand's ornithological community, Lyall's wren was very quickly wiped out once cats overran the island, and the disappearance is now firmly attributed to this growing feral population rather than to one animal acting alone. Beyond Tibbles and her descendants, the wren was already in a precarious position before the lighthouse was even built, since the species had already vanished from mainland New Zealand long before European settlers arrived, most likely wiped out there by kiore, the Polynesian rats brought over by early Maori voyagers centuries earlier. Stephens Island had simply been the last refuge left for a bird that was already running out of places to hide.
