They say timing is everything.
With less than a week to go until the public comment period ends for the proposed St Patricks Plains wind farm there’s been a timely reminder about the horrific deaths many of our iconic wedge-tailed eagles experience.
Even though the Tasmanian wedge-tail is the largest bird of prey in Australia, it’s no match for 100 tonnes of composite metal and carbon fibre spinning at 300 kph.
The x-ray shows an eagle cruelly bisected by a wind turbine blade. Unfortunately, this is not an isolated occurrence – but getting a clear picture of how many of these endangered birds are mutilated by energy assets is hard to come by.
Deaths at wind farms or along TasNetworks transmission lines are reported by the operators to the Environmental Protection Agency Tasmania, and scores, if not hundreds, of carcasses lie frozen at the Tasmanian Museum and Art Gallery, awaiting necropsy (an autopsy carried out by humans on other animal species).
With the last proper population estimate carried out 17 years ago, and with the Threatened Tasmanian Eagle Recovery Plan abandoned since then, guesstimates of around 1000 total, with maybe 600 breeding-age birds, is about it.
Knowing the number of eagles which have been killed is a starting point to understanding the remnant population. This information is not publicly available.
As a member of the Keep Tasmania’s Highlands Unique – No Turbine Action Group (NTAG) I made a start by tabulating known eagle deaths and injuries in the period 2010 – 2022. The information was recorded in a variety of annual reports. The result of this work was published last week in Australian Field Ornithology.
The complete paper can be read by following this link: https://afo.birdlife.org.au/afo/index.php/afo/article/view/2304.
321 eagles were reported maimed or killed – but the total will be much higher. The majority of wedge-tailed eagles which are hit by cars, or shot, or poisoned as they prey on mice laced with rodenticides or wallabies filled with 1080, are absent from the count. And not all wind farms now search for avifauna around their turbines. There’s been no systematic searches of the state’s two oldest wind farms at Woolnorth since 2014.
At a time when the Robbins Island wind farm project is embroiled in a TASCAT hearing, members of NTAG are busy writing detailed submissions rebuffing claims made in the 2000+ pages of the Development Application and Environmental Impact Statement released for the proposed St Patricks Plains wind farm.
Chief among those contentious issues is the number of eagles the EPA actually permits the operator to kill each year. That number is reached after human observers have charted eagle activity over the 10,000 hectare project area, and those numbers are run through a complex algorithm to come up with a theoretical annual death toll.
For the new project, calculated yearly deaths are 4.89 wedge-tailed eagles plus 0.05 white-bellied sea-eagles. A variety of mitigation measures are then applied – themselves the product of probability analysis manipulation – and we end up with interesting numbers for WTEs of 1.61 – 2.45 deaths annually.
While these mitigation measure range from the simple (but rarely-used) painting one of the huge blades back, to a complex series of tracking cameras which can quickly slow a spinning turbine if an eagle approaches, estimating the number of eagles present around a potential wind farm site, and their activity, is left to observers.
Over eight seasons, this quaint method, reminiscent of ‘twitching’, employed five people for two shifts of about 3.3 hours per day over a five day-week. A total of 3259 observer hours were logged. Armed with a pair of binoculars and a notebook, this method has its obvious limitations, and the report speaks of ‘observer fatigue’.
But for more than a decade, eagles in overseas studies have been fitted with GPS trackers which record their movements in real time.
So while turbine technology has grown better and bigger, Tasmania relies on an outmoded and inaccurate method to assess local populations of eagles, when best-practice methods are available.
It’s true, that with recent funding provided by wind farms as reparations for killing eagles, around 25 WTEs have been fitted with trackers. But no data from those birds have been used to inform the siting of wind turbines. In fact, the territories which these eagles occupy is mostly over pristine national parks – hardly likely to host a wind farm.
In step with an outmoded method of detailing eagles and their usage of an area, Tasmania has set a very low bar to protect eagle nests from disturbance. Designed 40 years ago to keep forestry operations away from trees with nests, a one-kilometre circular buffer was introduced.
While this is effective for trees, the turbines at St Patricks Plains will be 231 metres high – which is nine times the 25-metre average height of the surrounding bush, as it is described by a consultant’s report attached to the Environmental Impact Statement.
It takes little imagination to see that standards are set very low in Tasmania to give wind project developers an easy ride.
Combine a lax government attitude to threatened species conservation with dogmatic policies of ‘powerhouse’ supremacy, and the Tasmanian wedge-tailed eagle is facing a grim future.
Humans have created a existential predicament through excessive carbon emissions, but destroying apex predators like the wedge-tailed eagle does nothing but dig a deeper hole.
Featured image above: X-ray of a wedge-tailed eagle with a severed backbone, courtesy Nick Mooney.
Greg Pullen is a committee member of the Central Highlands No Turbine Action Group (NTAG) and has a keen interest in renewable energy transformation, in particular its benefits for Tasmania. He is a firm believer in the KISS Principle.
