Magpies under close scrutiny

By CATHY ARONSON

HAMILTON - The magpie's divebombing days may be numbered. Nine regional councils have banded together to prove that the bird is a big bully with a thirst for native birds.

Magpies are considered the most aggressive birds in New Zealand and attack anything that poses a threat to their territory, particularly during breeding season. They often divebomb and attack humans, birds and animals.

The magpie is classified as a pest but landowners are responsible for their control and regional councils only provide advice.

But the birds may have met their match if a three-year study, in Waikato, Northland, Southland, Wellington and Bay of Plenty, proves that the birds are destroying native bird populations.

Environment Waikato joined the study in July and for the next three years will monitor the birds in 900ha at Pirongia and Maungatautari, involving 23 landowners.

In Pirongia, all the magpies will be removed (300 have already gone); in Maungatautari, they will be monitored, before the numbers of native birds left in each region are compared

Animal pest programme manager Peter Russell said the magpies may be eradicated in sensitive ecological areas if the study found they were reducing native bird populations.

"If the trial gives us conclusive evidence then it may be the big crunch point for the magpies. But they couldn't be totally eradicated because they are so widespread. Where do you start and stop."

The project is coordinated by Landcare Research scientist John Innes, who was approached by Bay of Plenty and Wellington regional councils to do a literature review of magpie behaviour.

Mr Innes said the councils needed to conduct a large-scale experiment to establish the extent of the pest before spending money eradicating them.

"All around the country councils are fielding complaints and trying to resolve the same question - does the magpie have an effect on bird populations and should they try and control them. We need to gather solid data to guide councils on whether the magpie is a dead duck or a goer."

He said magpies harassed and sometimes killed other birds because they were aggressively territorial during nesting season.

Mr Innes said large groups of magpies patrolled bigger territories than other birds and marked their territories by singing their famous flute-like call "quardle oodle ardle."

"Basically they are bullies but magpies also have their fans. A lot of people like the magpie's song."

Magpies were introduced to New Zealand in Canterbury, Otago, Auckland and Wellington in the 1860s to control pastoral insect pests. By 1979, the magpies had spread to all suitable habitat in the country.