Campaigners have appealed against a ruling which gave the go-ahead for four controversial wind farm projects in the firths of Forth and Tay.
RSPB Scotland had objected to the developments which, they say, threaten thousands of seabirds.
After winning the initial challenge, an appeal was lodged by Scottish ministers and the ruling was overturned last month.
The charity has confirmed it has started a legal challenge.
It is seeking permission from the Inner House of the Court of Session to appeal to the UK Supreme Court.
RSPB Scotland director Anne McCall said: “RSPB Scotland continues to fully support the development of renewable energy and the vast majority of projects continue to pose no significant threat to birds or other wildlife.
“However, we are concerned that this judgment could set worrying precedents for the protection of wildlife across Scotland and the UK.
“In light of our concerns we have decided to start the appeal process by applying to the Inner House for permission to appeal to the Supreme Court.”
After last month’s ruling, one of the developers, Mainstream Renewable Power, said it would immediately press on with construction work.
The company estimates its project alone would create 500 construction jobs and more than 100 permanent operational roles.
The Inch Cape, Neart na Gaoithe and Seagreen Alpha and Bravo projects were approved by Scottish ministers in 2014.
It has been estimated that they could generate up to £1.2bn for the Scottish economy and power 1.4 million homes.
But RSPB Scotland raised concerns that the wind farms risked birds like puffins, gannets and kittiwakes.
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