Alien Predators Outsmarted by Birds
Recent research reveals that the New Zealand bellbird is able to change its nesting behavior if necessary in order to protect itself from predators. The finding is of massive importance since the introduction of alien predators has been a threat that shore birds have had to face for many years. Often this usually unintentional phenomenon results in the extinction of a number of endemic bird species and some 25 percent of all endangered species continue to be under threat from exotic predators.
The research was lead by Dr Melanie Massaro and Dr Jim Briskie who work for the University of Canterbury. Massaro feels that the impact of exotic predators is particularly noticeable on birds that are native to oceanic islands, chalking this phenomenon down to evolutionary concepts and the fact that the birds seem to be particularly naive about the dangers posed by these new animals. However, it would seem that the situation is not quite as dire as previously thought. After studying the bellbird, a species which is endemic to New Zealand, the researchers found that this previously naive bird was soon able to adapt its nesting habits in response to the threat that was posed by large numbers of exotic predators that had been introduced by humans. The birds were studied in high risk (predators a constant threat), recent low risk (the predators recently removed) and permanent low risk (predators never introduced) areas and it was found that females spent more time on the nest where there was an increased risk of predation. This defensive behavior minimized predator activity at the nesting site and decreased the risk of egg predation.
Over the centuries the introduction of a number of predatory or opportunistic mammals, such as rats, stoats and cats, has led to the extinction of a number of endemic island birds. However these new findings show that quite a few birds have at least a limited capacity to fight back. The marked increase in parental activity during the nesting period greatly reduced the risk of a predator destroying the nest. This shows that the birds are not trapped in a particular mode of behavior, but rather that they are able to adapt their routines in ways which are greatly beneficial to their young. Previously it was thought that this sort of change would take centuries occur, but instead it seems that these changes took place over a matter of only a few years. It is hoped that the new finding could help conservationists to encourage birds to respond to exotic predators and so help ensure their own survival – especially in such cases where these predators cannot be eliminated.