Filling up niches

[Leovb]

I have only arrived 6 weeks ago in NZ and again (I was here three years ago also);

- I hear people telling that where magpies arrive numbers of tui fall.
- Sulphur crested cockatoos are said to compete for nesting sites with endemic NZ birds (causing there numbers to decline) and the
  common myna is another threat to the endemic birds of NZ (on the north island).
- Rainbow lorikeets were caught and disposed of on the North Island as were bulbuls? (so people proudly told me) But what was the
  damage done by these species to NZ fauna or flora? Aren't they just filling up the huge gaps in eco-niches that are available over
  here?

Where are the underlying independent research results that confirm these statements for the NZ situation? Are NZ endemics really threatened by these "exotic pests"?

I do notice that here in NZ letting pet cats roaming free about during night and day is allowed and even in the bay where I live people own these killers and have them walking about freely. (Presumably to the detriment of the fantails, bellbirds etc that are still here.)

Does anybody know of research in these matters for the NZ situation? I would really like to know whether the statements about the exotic birds are correct and if significant damage is done by these birds to NZ fauna and flora. Untill that time I consider every bird that flies around in this beautifull country so poor in landbirdnumbers and variety as an added value to its beauty.

[Jamie Stewart]

  Seems a wierd dichotomy I'm sure, cherish the cat, kill the cockatoo.

Cats unfortunately are with us for another 50 years or so before we genetically modify them (like all the seeds these days) so they can't reproduce and we have to import them from someone licensed by Monsanto.

Cockatoo's on the other hand (and other such more recent invaders) have an unknown effect and the potential to spread into the environment much more rapidly so we remove this possibility. Its called the precautionary principle.

If there is one thing you quickly discover about wildlife research in New Zealand its how little we know. We didn't know until recently for example that 1080 kills keas...although that said there are certainly people that know an awful lot