Cat and wren game
This single square mile of land off the northern tip of New Zealand's South Island had never been settled by humans and was therefore the last hiding place for many of the species that had once inhabited the entire archipelago.
For one of these species, however, the construction of a lighthouse was to have tragic consequences. The Stephen's Island Wren, Xenicus lyalli, which almost certainly arrived in New Zealand some 40 million years ago as a wind-blown migrant, had the rare distinction of being the only flightless songbird in the world ever to be seen by Europeans. But together with its flightless relatives, the thick-thighed and long-billed wrens, it had disappeared from all but Stephen's Island, courtesy of the Pacific rats which the Maori brought with them in the 10th-century.
And now, even Xenicus lyalli's apparent ability to run as fast as a mouse would not save it, thanks to the arrival on the island of a creature whose ability to catch mice was its very reason for being there. The creature in question was Tibbles, the lighthouse keeper's cat, who in 1894 is thought to have single-pawedly wiped out the entire remaining population of Stephen's Island wrens.
According to records, the hard-working mouser presented its master with no fewer than 16 entire corpses that year, and these were soon to become collectors' items. But sadly, while the slaughter was continuing, nobody thought to check how many wrens remained on the island. When the supply abruptly dried up, it was too late to conduct such a survey, and it simply remained to report the discovery and the extinction of the Stephen's Island Wren to the outside world.
It was in fact the only time in history that the discovery and extinction of a bird was reported simultaneously, and certainly the only time that a single individual has been responsible for both events. The individual in this instance being Tibbles.