Migrating godwits will carry radio beacons on southern flight

29 August 2005

Scientists will be watching with interest over the next month as several bar-tailed godwits carry a slightly heavier load as they travel from their breeding grounds in the Alaskan tundra to estuaries around New Zealand.

Over the last year about 400 New Zealand godwits were given individual markings - lightweight coloured bands on their legs.

Recently a team from the United States Fish and Wildlife Service has been searching remote Alaskan estuaries and river deltas, searching for Godwits banded here and in some of the other countries to which they migrate to escape the arctic winter. The first Christchurch arrivals are expected in mid-September.

The bands allow researchers in New Zealand and overseas to learn more about their movements. For instance, this work has helped confirm that most godwits which come to New Zealand are from Alaska. It had been thought they bred in Siberia.

“It’s also been discovered that instead of migrating by island-hopping down through Asia and Australia, these Alaskan-breeding godwits probably fly directly across the Pacific in a flight of about 11,000km which the fastest birds can complete in six to seven days,” says City Council ranger Andrew Crossland.

That supposition will be tested in the next few weeks thanks to the Fish and Wildlife team which has been catching a small number of birds and attaching tiny transmitters to them.

The American research team scouring the Alaskan wetlands has also been looking for New Zealand-banded birds. So far, they have identified at least 20 New Zealand birds in recent weeks, including four which were banded in Christchurch.

Dr Phil Battley from the University of Otago’s Mathematics and Statistics Department is leading the New Zealand end of this project. The ecologist says researchers hope the signals given off by the 2g beacons will pinpoint departure times and provide more information about learn more about the migratory route, weather encountered on the way and how long it takes a bird to make the journey.

“A series of receiving stations is being set up throughout the country from the Far North to Christchurch,” Dr Battley says. “This will allow researchers here to monitor key sites on a daily basis and pick up radio-tagged birds within hours of their arrival.”

Based on past experience, the first migrating godwits are expected to arrive in Christchurch around mid-September. Celebrations to mark the arrival are planned.

• More information about Dr Battley’s work with shorebirds is here on the web

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