Stephens Island Wren
Stephens Island is a tiny speck of land, just 1.5km², located between New Zealand’s North and South Islands. Despite its small size, it is internationally important because some of the animals that live there are found nowhere else on Earth. These include the large flightless ngaio weevil and one of the rarest frogs on the planet, Hamilton’s frog. But Stephens Island is arguably even more famous as the final refuge of a special little flightless songbird – and the place where it was lost forever.
When the Maori first arrived in New Zealand over 700 years ago, they brought with them the Polynesian rat, which wreaked havoc among the island’s flightless endemic birds. One bird, in particular, suffered immensely at the hands of these rats. Later known as Stephens Island wren, this species was the last remaining flightless songbird in the world. By the late 19th century, the bird had vanished from mainland New Zealand and survived only on a tiny, rat-free island that would, in time, give it its name.
Even when Europeans arrived on New Zealand, Stephens Island was largely ignored by them. Until, that is, the 1890s, when a lighthouse was built upon it. In 1894, three lighthouse keepers and their families moved onto the island – but most critically, they also brought cats with them. One of the lighthouse keepers, David Lyall, became interested in the bird specimens that his cat Tibbles brought back to him and he sent them off for expert analysis. These specimens were soon identified as a brand new species unknown to science.
Unfortunately, the cats proved so effective at catching the flightless wrens – and the wrens themselves, which functioned ecologically as avian mice, were so ill-prepared to deal with mammalian predators – that when the scientific community officially declared the Stephens Island wren a brand new species a year later, David Lyall had to regretfully inform them that it was likely already extinct. People searched the island for evidence of the bird’s continued survival, but without success.
It is often said that Tibbles single-handed exterminated the last remnants of this species, bringing their bodies back, one by one, to her master. A good story, perhaps, but almost certainly untrue, for there were several other feral cats on the island and they undoubtedly contributed to the wren’s demise.
The news of the bird’s discovery was reported to the world at almost the same time as its extinction was. Very few Europeans saw a living Stephens Island wren and, as such, we know almost nothing about it. According to a letter sent by the New Zealand naturalist, Henry Travers, the bird was only seen alive on two known occasions, when disturbed from holes in the rocks. It was described as nocturnal and capable of running very fast, like a mouse. Today, the only things that remain of this species are the cat-chewed specimens collected and sold by the lighthouse keepers on Stephens Island, twelve of which can still be found in museum collections. Now, sadly, there are no flightless songbirds left in the world whatsoever.