Birds Introduced To New Zealand

Bird On! News
29th March 1997

The sins of the fathers are visited on the later generations in a big way in New Zealand. The Maoris ate and used the feathers from the Moas - huge flightless birds which are now extinct - and the European settlers persisted in introducing large numbers of different birds to 'improve' the variety of birds in the country at large. This had a devastating effect on the native birds that were also having to cope with ground predators like cats and rats for the first time.

Rhys Green has used these disastrous events to look at what in the introduction episodes influenced their chances of success. His report in the Journal of Animal Ecology (66, 25-35) is about 47 species (of a staggering 133 for all known introductions) from about 100 years ago. Of these 21 had surviving population up to the 1970s. Basically the chances of survival were very strongly enhanced by the release of more birds originally. Of birds with 100 or more individuals released within ten years 83% survived, with those with less only 21% persisted.. All other factors tested for were far less important and Rhys considered that none of them could be considered significant - except that families with several introductions were more likely to have success than not. May be this was selection by the introducers for birds which were likely to succeed?