New Zealand Journal of Ecology (2010) 34(1): 152- 157

Do New Zealand invertebrates reflect the dominance of birds in their evolutionary history?

Review Article
George Gibbs  
  1. Research Associate, School of Biological Sciences, Victoria University, PO Box 600, Wellington, New Zealand

Pre-human New Zealand had some unusual feeding guilds of birds (e.g. the herbivorous moa fauna), thought to have developed as a result of the absence of a ‘normal’ mammal fauna. Insectivorous birds, on the other hand, are an integral part of all the world’s ecosystems, regardless of the presence or absence of mammals. While it is acknowledged the overall predation impact from birds in New Zealand is unlikely to have differed greatly from elsewhere, the low impact of mammalian insectivores (apart from microbats), coupled with the presence of a specialised avian feeding guild that concentrated on ground-active prey, might have exerted certain unique selection pressures. Do New Zealand invertebrates reflect this? It would be necessary to compare the New Zealand invertebrate fauna with that of mammal-dominated lands in greater detail than is available today before we could assert whether any unique anti-predator characteristics have evolved. Knowledge of the insects that succumbed to extinction when mammals invaded New Zealand should provide clues to avian-adapted features that might have rendered them particularly vulnerable to introduced rodents. Predation by kiwi (Apteryx spp.), an extraordinarily mammal-like nocturnal bird, may to some extent have prepared the invertebrate fauna for the arrival of small mammals.