The Stephens Island Wren has a rare place in ecological history. Not only was it one of only three flightless songbirds in the world, it also holds the distinction of being the only known species on Earth to be entirely wiped out by a single being.
Stephens Island, or Takapourewa to the Maori, covers an area of 2.6km2 (1mi2) and is the most distant island off the northern tip of New Zealand's South Island. Named in honour of Admiralty Secretary Philip Stephens by Captain James Cook, the island was located on a shipping route and hence deemed an appropriate place to build a lighthouse. So, in 1894, Stephens Light became the residence of one Mr David Lyall.
Tibbles the Cat
A companion to Lyall, the lighthouse keeper, Tibbles the cat soon made Stephens Island her home and hunting ground during 1894. It was not long before she was presenting her master with gifts of local wildlife — in particular, a small bird which was unlike any that Lyall had ever seen. After Tibbles brought him a handful of the birds, Lyall shared his find with a Mr Henry Travers of Wellington.
Eleven of the birds were brought to Lyall by Tibbles in almost pristine condition, as she seemed to enjoy the act of the chase and the kill rather than eating the birds. The discovery quickly found its way to Sir Walter Buller, New Zealand's ornithological expert at the time. A duly excited Buller reported the find to the British Ornithologists' Club in London after classifying the bird as a member of the wren family.
Due to Tibbles' expert mousing skills (or indeed, 'birding' skills), the wren colony on Stephens Island, perhaps a total of ten mating pairs, was extinct within the year of discovery. In fact, so successful was Tibbles in her apparent genocide that the Christchurch Press reported in 1895 that:
...there is very good reason to believe that the bird is no longer to be found on this island, as it is not known to exist anywhere else, it has apparently become quite extinct. This is probably a record performance in the way of extermination.
The lighthouse cat had possibly single-handedly (or paw-edly, if you prefer) disposed of the bird, a feat exasperating in its seemingly senseless execution. Buller himself stated in 1905 that:
...it would be as well if the Marine Department, in sending lighthouse keepers to isolated islands where interesting specimens of native birds are known or believed to exist, were to see that they are not allowed to take any cats with them, even if mouse-traps have to be furnished at the cost of the state.
The 'Lyall' Wren
The wrens that made up Tibbles' nighttime entertainment were, before becoming extinct like the Dodo of Mauritius, thought to have originated from a time when Australia and Antarctica made up the ancient landmass known as Gondwanaland.
The Stephens Island Wrens (Latin name: Xenicus (Traversia) lyalli, sometimes referred to as the 'Lyall' wren) were typical of most New Zealand wrens. With a mottled dark-olive appearance and yellow-green tinge to the throat and breast, they were very small and also flightless, like their cousins the kiwi and kakapo. Nocturnal birds, the wrens made their nests in holes or under rocks, much like the puffin, and fed upon small insects. Seen to scamper about at night, much like a mouse, this is perhaps why Tibbles was so keen on hunting them down1.
It is also interesting to note there is a British tradition of 'hunting the wren' performed, coincidentally, on St Stephen's Day. Legend has it that when St Stephen was hiding from his enemies in a bush, he was betrayed by the chattering of a wren and thus captured and stoned to death. For this reason, on St Stephen's Day groups of young men would go out and hunt wrens and then parade their kills around their village hoping that good luck would befall them, or at least a palm crossed with silver or gold for their 'bravery'. Perhaps Tibbles was thinking her actions would bring good luck to the island, or maybe the small birds were unwittingly named after European wrens in honour of this custom.
From fossilised remains found all over New Zealand, proof was obtained of the species once inhabiting the entire country. It was most likely killed off on the mainland by rats introduced by the Maori and other ground-based predators. Some of the wrens caught by Tibbles and later preserved can be seen at the British Museum. Although pretty to look at, it is more saddening that their song will never be heard.