A contentious wind farm proposed for Tasmania's north-western tip could interfere with the recovery of a critically endangered parrot species, documents obtained under right to information laws show.
The proposal could also significantly impact a population of Tasmanian devils, which are thought to be key to the species' survival.
The proposed Robbins Island wind farm would be situated within the known migration pathway for the orange-bellied parrot, a species that is believed to have dwindled to just 70 adult breeding birds in the wild.
Robbins Island is considered to be essential for the survival of the species.
Documents prepared by Tasmania's orange-bellied parrot (OBP) program last August found the wind farm could create migration barriers, kill birds that collide with the infrastructure, reduce critical habitat, modify or destroy habitat to the extent that the species is likely to decline and interfere with recovery of the species.
"The proposed wind farm is located within the known migration path of the OBP. There is no uncertainty associated with this. Whether collision will occur is unknown, but the potential for it to occur exists," the documents say.
The documents criticise proponent UPC/AC Renewables' phrasing in earlier documentation that no more than a "handful of birds" would use the area, saying it was a "poor choice of words" given even five birds would constitute 10 per cent of the wild population.
"The loss of any individuals due to collision, disturbance or barrier effects during construction or operation represents a significant risk to the species given the small adult population size," the documents say.
"It's worth noting that with the current population estimate one bird is equivalent to 2 per cent of the population.
"The proposal, therefore, has the potential to seriously disrupt the life cycle ... of an ecologically significant proportion of the population."
The analysis found the proponent's plans to manage orange-bellied parrots underestimated the risks posed to the species, said surveys undertaken were not sufficient and criticised the limited UPC/AC Renewables' proposal to search just 30 per cent of its turbines monthly for carcasses, saying the strategy was unsuitable.
A spokesman for UPC/AC Renewables said the information obtained in the right to information documents was compiled prior to the finalisation of its development application to the local council, which the company believes addressed the concerns raised.
They said a comprehensive preliminary orange-bellied parrot monitoring and management plan had been developed as part of the approvals process, and that a final plan would be developed prior to construction beginning if the project wins approvals.
BirdLife Tasmania's Eric Woehler said the orange-bellied parrots migrated through the Robbins Island passage twice each year, and even one death would be too many for a species on the brink of extinction.
"It's got to a point where the numbers are so low the pressures on those individuals that are left are so great, whether it's disease, whether it's a fire, whether it's a wind farm, the loss of any individual bird poses an incredible risk to the increased likelihood of extinction, and it's unacceptable," Dr Woehler said.
"It's impossible to imagine how you could have a wind farm of that scale in a wetland inside the migration corridor and not kill birds."
Dr Woehler said the Robbins Island area should be declared an internationally recognised Ramsar wetland, given it met at least six criteria for listing.
"It's the highest quality wetland in Tasmania, and certainly the highest quality wetland in Tasmania that's not protected at the moment," he said.
Greens MP Rosalie Woodruff said while there were other sites for a wind farm, there was no other place for the parrots.
"We're seeing this population coming back from the brink, but a wind farm on Robbins Island would decimate that population," she said.
Federal environment department wants proof parrot risk 'remote'
Last October, the federal environment department wrote that it had concerns about the level of risk of orange-bellied parrot collisions, and the way fatal collisions would be managed.
The right to information documents show the Department was critical of the way UPC/AC Renewables planned to respond to fatal parrot collisions and called on the proponents to prove the collision risks were "remote".
The federal environment department was also worried the impacts from the wind farm on Tasmanian devils would be significant.
According to the documents, devils are "widespread and abundant" on Robbins Island, where the population has not been hit by devil facial tumour disease.
The area is described as a "likely stronghold for the survival of the species".
However, Tasmania's EPA did not share concerns that there would be a significant impact on the devil, so long as planned management and mitigation measures were implemented by the proponents.
The impacts on the orange-bellied parrot and devil habitat appear to have been a sticking point as the proponents navigated the approvals process with the federal environment department.
The documents show a back and forth between Tasmania's EPA and the proponents in which EPA staff suggest tweaks, which the Greens have labelled "very concerning" — a sentiment also shared by Dr Woehler.
"It smells very much like the EPA is being employed to do the work of facilitating developments like massive wind farms on critically endangered bird habitat," Ms Woodruff said.
Tasmania's Environment Protection Authority said engagement between its staff and the proponent was required at a number of stages throughout the process of developing an environmental impact statement to ensure the guidelines were adequately addressed and the public had access to accurate information.
The EPA is still assessing the wind farm project.
UPC/AC Renewables said it had provided additional information to the EPA where it was sought.
Once the EPA's assessment is finalised, it will be forwarded to the federal environment department for further assessment under the Environment Protection and Biodiversity Conservation Act, before a decision can be made on whether the wind farm proceeds.
