Kaka damage trees when looking for tasty sap. Iamge by Arthur ChapmanTrees to get the chop after parrot damage
Zealandia's neighbours are victims of the sanctuary's success as its booming kaka numbers strip tree bark in their ceaseless search for sap, a study has found.
The Victoria University research shows Wellington's Botanic Gardens are among the sites being targeted by the native parrots.
UNIMPRESSED: Botanic Gardens manager David Sole.Gardens manager David Sole said the problem was serious and had spread city-wide, from Island Bay to Ngaio. "Some of our trees are getting an absolute hammering, to the extent that we're going to have to cut them down."
Kaka were especially fond of the gardens' stock of North American conifers, including decades-old heritage specimens.
Getting rid of exotic conifers and replacing them with more kaka-resistant natives was being considered. However, he would never call for a kaka cull.
"Kaka were here long before people . . . We're not going to go back to shooting them. We've just got to work it out."
Study author Kerry Charles said there were up to 250 kaka in Wellington city, a number that had grown quickly over recent years.
The study also found people welcomed the birds, and were willing to put up with superficial damage to trees, joinery, weatherboards and guttering.
"The vast majority of people absolutely love having kaka around, so they're willing to tolerate minor problems," Ms Charles said. Even if kaka numbers proliferated, they would never cause the same level of destruction as their mountain cousins, the kea.
Methods being developed for repelling the notoriously inquisitive kea could be used to curb kaka too, she said.
DAMAGED: Trees, such as this one, are getting so damaged they will have to be cut down.Her study recommends monitoring dangerous, damaged trees, keeping trees that kaka like for sap in safe feeding areas, and planting more damage-tolerant species on public and private land.
Homeowners are also advised not to feed kaka.
Australia's destructive native parrots showed how serious the problem could get if not handled properly, Ms Charles said in her report.
"The Australian experience demonstrates the potential for intelligent parrots to generate serious and intractable conflict in urban areas, and highlights the importance of understanding and managing urban wildlife issues proactively."