Researchers are poised to see whether TrustPower's new wind farm at Mahinerangi has any effect on the New Zealand falcons.
They have found nests and nesting pairs and are using radio transmitters to monitor the birds' pre-turbine movements.
Five pairs have been identified to the north and west of the wind farm, within a 5km radius of the farm. No nests were found in the wind farm itself.
Dr Richard Allibone, who manages the Mahinerangi ecological work for environmental consultants Golder Associates, called the work "potentially far-reaching".
Golder Associates' work - a condition of TrustPower's resource consent - was entering its third year and it had a significant body of pre-wind farm data.
That meant it would have plenty of information on which to draw to see whether the wind farm's turbines affected the falcons.
"Having that comparison data means we're in the position to learn a great deal about the impact, if any, of the wind farm.
"It will be information that could be useful for other wind farm developments, and it could be used to understand how to mitigate any impacts."
However, they were still some way off knowing how the birds would be affected when the first stage of the farm was commissioned in May.
Falcons did not like unfamiliar things, and they might avoid the wind farm area until they got used to seeing the turbines.
It was also too early to say whether birds focused on land-based prey could inadvertently fly into turbines, Dr Allibone said.
"The turbines are dispersed, so there are ways for birds to get through, but if we knew the answer to that question we wouldn't have to do the work."
Recent observations suggested falcons were disrupted by changing land use, such as grazing, which affected nesting sites.
