Do windfarms kill birds? Unarguably, they have and do.

The damage turbines can inflict was infamously highlighted at California’s Altamont Pass, where early industry farms were built in a migratory path. One estimate suggested it killed as many as 1,300 birds of prey a year before changes were made to reduce death rates.

But is it a problem in Australia, which now has about 90 windfarms and another 25 on the way?

The question has received a burst of attention since the country’s most celebrated conservationist, Bob Brown, strongly objected to a windfarm proposed for Robbins Island, off the north-west Tasmanian coast.

Developer UPC Renewables plans to erect up to 163 turbines on the privately owned island. The towers could reach up to 270m high from ground to blade tip. Brown’s criticism is broad, taking in the visual impact, plans to export the electricity to Victoria and the company’s foreign ownership. But it is mostly centred on the threat to migratory birds.

After some initial straight reporting, media coverage of Brown’s comments became absorbed into a culture war over the validity of renewable energy. Commentators mostly ignored that the Robbins Island proposal is still at a relative early stage, with planning and environmental applications yet to be submitted.

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The circumstances at Robbins Island are unusual for an Australian windfarm proposal as the site sits next to an intertidal mudflat visited by several migratory species. But in other parts of the country the evidence that windfarms are a major problem for birds is limited, if the projects are appropriately sited and managed.

Emma Bennett is an ecologist who has been employed by energy companies to monitor bird and bat kills at about half the windfarms in Victoria. She says while there is good global information, there is a lack of peer-reviewed data about the impact of turbines on Australian bird populations.

Bennett developed a technique to estimate bird and bat kills. Trained observation groups and detection dogs are used to find small birds and bats near turbines. Bird carcasses from elsewhere are left and monitored at windfarms to see how quickly scavengers remove remains. “We use that to develop an estimate of the impact of the turbines,” Bennett says.

She says her results suggest that on average one or two birds are killed by each turbine each year, though there can be variation depending on the site. “We get really low counts, even lower than studies from overseas,” she says. “If you look at the global trend, bats tend to be at greater risk than birds. That’s also coming out in Australia and they get much less attention.”

After 15 years working with the industry, she believes the money energy companies spend on bird and bat monitoring – estimated at between $20m and $120m over the next decade in Victoria alone as the state installs about 1,000 more turbines – could be better directed elsewhere. She says some individual monitoring should continue, but wants industry and government to back a research fund that would look at the cumulative impact of windfarm development on threatened species.

“What we want to do is, by pooling all our data and identifying the species most at risk where windfarms are built, work out how to limit risks and offset impacts before they begin,” Bennett says.

Part of the money would be spent addressing the biggest problems faced by threatened bird species that live near or pass by windfarm developments. It would go to restoring critical habitat, such as wetlands, and reducing fox and feral cat numbers. Research suggests cats kill a million of birds across Australia each day.

“If we can leverage funding from what is a small threat to address larger threats then we will get a better outcome for species at risk,” she says.

The whole-of-state approach could help shape where windfarms should be built with a goal of helping species most at risk, such as brolgas, which are threatened in Victoria, and the critically endangered orange-bellied parrot.

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Eric Woehler, an ecologist and convenor of Birdlife Tasmania, is cautious about engaging in what has become a media-driven ideological battle against green energy but believes the number of birds killed per turbine is greater than Bennett estimates. He says averages can be misleading as a significant number of birds, particularly large raptors such as wedge-tailed eagles and some waterbirds, can be killed by relatively few poorly sited turbines.

But he agrees windfarm developments should be looked at strategically and cumulatively. Woehler says state and federal governments need to work together to determine where renewable energy developments should be built to further limit bird kills. He says that should include more no-go areas based on their national and international environmental significance.

“There is a clear and obvious need for Australia to shift to renewable energy. We need to do it in such a way that it doesn’t pose additional and novel threats to our biodiversity,” he says. “As a sweeping generalisation, every windfarm kills birds. Individual windfarms kill birds depending on the siting or micro-siting of the turbines involved.”

Woehler has particular concerns about the Robbins Island development. He says turbines there could have a disproportionate impact on about 20 migratory species including several endangered and critically endangered migratory species, such as the curlew sandpiper, far-eastern curlew and red knot.

The company plans to lodge a development application within weeks.