Extinct Giant Bird Doomed by Slow Growth, Study Says

The large, flightless moa bird that roamed New Zealand in ancient times grew much more slowly than modern birds, according to a new study of their bones. The finding suggests that slow growth doomed the moa to extinction when humans arrived about 700 years ago.

Unlike the bones of all modern birds, several moa bones show growth marks similar to the rings found on tree stumps, said Samuel Turvey, an ecologist at the Zoological Society of London in the U.K.