Offshore wind farms are established across large parts of Europe, but it's unclear what damage they're causing to seabirds. Source: Getty

As Australia prepares to massively expand offshore wind farms across six priority zones, a group of researchers is racing to unlock the mystery of how much of a risk their blades pose to migratory seabirds.

During high winds, 100 to 200-metre-long wind farm blades can rotate at 290km/h, theoretically making mincemeat out of anything that collides with them. While this sounds alarming, it's not known whether seabirds are actually flying at the height they operate at.

Monash University’s Dr Mark Miller and his team studied how high, fast and at what time of day iconic migratory species like albatrosses, petrels, shearwaters and storm-petrels tend to fly. And while there's still more work to be done, their newly published study indicates the risk could be low.

“These offshore wind turbines are huge, and the distance between the bottom of the blade and the sea surface is around 35 metres. So if you could say all the birds fly under 35 metres, then that’s mitigating a lot of the collision risk,” he told Yahoo News.

“What the evidence is telling us is that seabirds fly quite low to the water, but the point is that the evidence is very limited.”

If it's confirmed that all birds in their path fly low to the water, then raising the height of turbines could provide a simple solution that reduces collision risk.

Researchers have examined the potential impact wind turbines could have on migratory birds visiting Australia. Source: Monash University/Jessica Zhou

But more research would be required to better understand the flight paths of other birds, like the critically endangered orange-bellied parrot and swift parrot, which migrate from Tasmania to the mainland.

The impact of turbines is likely to be lower than other threats like plastic ingestion, commercial fishing, habitat destruction and climate change, which are thought to be contributing to the deaths of over a million seabirds a year.

But migratory seabirds cannot afford to face any new dangers. Around a third are threatened with extinction, and populations have reduced by 70 per cent in just 50 years.

Researchers looked at the flight of iconic birds like albatross. Source: Rohan Clarke/Monash University

Mystery over how many birds collide with offshore wind turbines

Not only is seabird flight data limited, but so is information about how many birds offshore wind farms kill.

“Onshore, if something gets hit, you have people doing surveys. But at the moment, if a bird collides with an offshore turbine, it falls in the sea, and you have no evidence of that mortality,” Miller said.

While there are plans to install cameras on offshore turbines, once the farms are installed it will be too late to modify them. And they’ll sit in place for 20 to 40 years.

The Monash team is hoping their study, which was published in the Journal of Applied Ecology will help guide policymakers and the wind farm industry before construction begins.

Study co-author Associate Professor Rohan Clarke said it's possible to ensure that new renewable energy projects are good for both humans and wildlife.

“One of the key challenges we face is what’s known as the ‘green-green dilemma’, where initiatives designed to reduce environmental impact, such as renewable energy development, can unintentionally harm other ecological values,” he said.

“But we must identify evidence-based solutions to these competing priorities, because climate change remains the single greatest threat to biodiversity. The energy transition isn’t optional, it’s essential, and finding solutions that support both climate goals and nature is critical.”

This article originally appeared on Yahoo News Australia at https://au.news.yahoo.com/big-question-remains-as-scientists-tackle-mystery-of-wind-farm-risk-as-major-australian-projects-begin-034518339.html