Slow growth ‘wiped out’ moa

The moa were a family of giant, flightless birds. The extinction of New Zealand’s giant, flightless moa birds may have been hastened by the long time they took to reach maturity.

UK and New Zealand scientists studied growth rings (similar to tree rings) in leg bones from the giant birds. They found that moa took about 10 years to reach full size and then several more to reach sexual maturity. This left them vulnerable to human hunters who got to New Zealand 700 years ago. The hunters may simply have wiped out the birds by picking them off before they had a chance to become parents. Their slow growth was the result of a particular

life history strategy. It may have enabled them to invest their reproductive effort toward the production of a few, large young. This was possible because moa lived on an island with no natural enemies apart from giant eagles. But this all changed with the arrival of Polynesian colonists in about AD 1300. — Agencies