Because of its geographical isolation, New Zealand has a unique population of native animals. Until fossil evidence showed otherwise in 2006, it was believed that there were no mammals native to New Zealand that did not swim (marine mammals) or fly (bats).
But there was an ecological niche that, in the rest of the world, was occupied by mice. In New Zealand, that niche was occupied by the flightless Stephen's Island wren (Xenicus lyalli). Its Latin name is taken from the lighthouse keeper who first described it scientifically, David Lyall.
The wren became extinct in 1894. Legend has it that David Lyall's cat, Tibbles, was single-handedly (single-pawedly) responsible for the demise of the Stephen's Island wren. It is more likely that the wren was hunted to extinction by feral cats or rats introduced to New Zealand by human settlers.
And who arrived to occupy that now-empty niche? Immigrant mice.