One of Australia’s largest planned wind farms has been given the go-ahead by environmental regulators – but only if the A$1.6bn ($1.1bn) project's turbines are idle for five months of the year to protect an endangered parrot.

The draconian restriction is included as a condition for the up to 900MW, 121-turbine Robbins Island Renewable Energy Park proceeding in northwest Tasmania, with the state’s Environment Protection Authority (EPA) deciding the shutdown is needed over two annual periods of migration by the orange-bellied parrot.

The Robbins Island project is being advanced by ACEN Renewables, the clean energy arm of Philippines giant Ayala, which claims the site is “one of the windiest in Australia” and wants to export its output via a 115km transmission line to the Tasmanian grid.

The EPA said: “The board has concluded that significant mitigation measures are required regarding potential impacts on the orange-bellied parrot population given the limited knowledge about the importance of Robbins Island in the annual northern and southern migrations.

“This has led to the inclusion of condition FF6 which imposes shutdown periods during the migrations totalling five months when the turbines cannot operate.”

ACEN on its website says it has come up with a preliminary orange-bellied parrot management plan. Recharge has contacted the developer for comment on the EPA’s five-month shutdown stipulation, which would cover the period from 1 March to 31 May and 15 September to 15 November “unless otherwise approved in writing”.

The orange-bellied parrot joins other bird species around the world that have caused headaches for wind farm developers, such as the kittiwake which has forced costly mitigation measures at some of the North Sea’s biggest offshore projects.