In the last ten days there have been announcements about two different giant birds that used to live in New Zealand. There’s a human-sized penguin that flourished during the Paleocene – the first age after the dinosaur extinction event – and a one-metre tall parrot that lived some tens of millions of years later in the early Miocene. That era is still ancient to us: it lasted from 23 to 5 million years ago, so the one thing that we can say about this giant parrot is that it’s dead.

It’s not surprising that either species of bird existed. Island gigantism (or, sometimes, its flip-side, dwarfism) is a known evolutionary phenomenon associated with isolation. And New Zealand was literally the lost world of Professor G. E. Challenger – a place where the surviving dinosaurs – birds – dominated. When humans first arrived around 1300 AD (give or take a few…