Figures show seven endangered wedge-tailed eagles have been killed by electricity infrastructure in the first four months of this financial year.
The Department of Primary Industries, Parks, Water and Environment statistics show two eagles were killed at the Musselroe Bay wind farm in North East Tasmania.
TasNetworks annual report for 2016-17 revealed 15 birds, including 12 wedge-tailed eagles, a white-bellied sea eagle, a grey goshawk and a masked owl were killed.
Australasian Raptor Association spokesman Nick Mooney said the figures would be an underestimate because there was no systematic reporting.
“The electrocution reporting is just a drop in the bucket, but it is the biggest killer now, more than shooting and road kill,” Mr Mooney said.
He said it was estimated there were about 350 breeding pairs in the state – about the same level as 2005.
Mr Mooney said the deaths were serious because the eagle was a slow breeding bird that produced only one or two young and did not breed every year.
“They have very little ability to compensate for extra mortality by extra breeding, unlike rabbits or starlings,” he said.
“These deaths are premature deaths that rob eagles of reproductive potential.”
Birdlife Tasmania convener Eric Woehler said superficially it would be concerning that seven birds had been killed in four months, especially if extrapolated over 12 months.
“But it may be that an improved culture of reporting by TasNetworks staff and by the public is an explanation, so there needs to a caveat on any conclusions,” Dr Woehler said.
A TasNetworks spokesman said the birds had met a variety of fates.
“A white-bellied sea eagle and a masked owl were believed to have collided with our infrastructure and suffered severe injuries, so both birds were euthanised,” he said.
He said a grey goshawk was electrocuted on a pole top in West Moonah.
“Thirteen wedge-tailed eagles were electrocuted by a combination of perching on pole tops and colliding with our conductors between poles,” he said.
The spokesman said the company would spend more than $600,000 this financial year on installing equipment to reduce the impact on threatened birds.
“We reduce risk by a combination of installing bird perches and bird flight diverters [flappers] on the conductors in high-risk locations,” he said.
“This financial year we are installing more of this type of mitigation on our existing network than ever before targeting numerous sites around the state particularly in the Midlands and North-East.
“We are also supporting research that is aimed at allowing us to better understand bird behaviours and movements so that future management techniques can be targeted in high-risk areas.
The latest figure compares with 11 wedge-tailed eagle deaths in 2015-16, seven in 2014-15 and five in 2013-14.
The latest Musselroe wind farm annual environmental review for 2016-17 reveals mortalities exceeding the expected levels since the farm was commissioned in October 2013.
“Since the commissioning through to the end of the current reporting period, seven wedge-tailed eagles and one white-bellied sea eagle had been identified as turbine collision victims,” the report said.
“Since  five wedge-tailed eagle collisions were recorded through to the end of the current reporting period representing exceedances of the threshold.
“These five collisions require the implementation of corrective actions.
“Corrective action is required because the rate of collisions has exceeded the expected rate and because the total number has exceeded six mortalities for this species.”
Woolnorth Wind Farm Holdings annual environmental review for 2016 reports there were no eagle collisions at either Bluff Point or the Studland Bay wind farms.
In the years from 2007 to 2010 Woolnorth killed 22 eagles and sea eagles.
Dr Woehler said Woolnorth had adapted the use of four turbines, which had been responsible for a significant percentage of deaths.
Two new wind farms are due for construction in the next two years.
Owners of the Cattle Hill Wind farm near Lake Echo on the Central Highlands have predicted that there will be 2.1774 fatal collisions with the 100 Vestas turbines per year.
A 2010 survey by consultants found 29 identified wedge-tailed eagle and six white-bellied sea eagle nests within 10km of the wind farm with estimates that breeding pairs were about half that number.
The Environment Protection Authority assessment of the Granville Harbour wind farm concluded wedge tailed eagles and white-bellied sea eagles were “unlikely to be significantly affected” by the proposed transmission system.
Mr Mooney said modelling of wind farm mortalities consistently underestimated the numbers because there was limited searching under a minority of turbines.
“Lightly injured birds who limp off to die elsewhere will not be counted even if found,” he said.
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