RSPB Scotland opposed to SSE's Strathy South wind farm
RSPB Scotland has described a 47-turbine wind farm planned for north east Sutherland as "one of the most worrying it has ever seen".
Energy giant SSE's Strathy South scheme is proposed for a site in the Flow Country - a vast expanse of peatland.
The RSPB said the site, a plantation of non-native conifer tree, should be restored to peatbog.
SSE said it recognised the importance of the habitat and that its project would involve restoring degraded peat.
The power company was given consent for 33 turbines at Strathy North in 2011.
It applied to the Scottish government in 2007 for permission for 77 turbines at Strathy South, but has since reduced the size of the scheme.
RSPB Scotland said the new site, a non-native conifer tree plantation, should be restored to peat bog. It added that the area was also home to rare birds.
The charity said birds included golden eagle, hen harrier, merlin, black-throated diver, red throated diver, greenshank and golden plover.
Stuart Housden, director of RSPB Scotland, said: "This is, without doubt, one of the most worrying wind farm applications we have seen in Scotland.
"Not only does it risk harming some of the UK's rarest species, it would make restoration of this core part of the globally important Flow Country much more difficult."
He added: "Wind farms play a vital part in tackling climate change but damage to our most important places for wildlife must be minimised.
"Over the last few years, SSE have shown that they can be a responsible developer, abandoning or amending some proposals elsewhere in Scotland that would have harmed wildlife - but this proposal sticks out like a sore thumb in their current portfolio."
The Scottish Wildlife Trust (SWT) also opposes the proposed wind farm.
SSE said it had consulted RSPB Scotland and Scottish Natural Heritage (SNH) on the scheme.
Nicki Small, Strathy South Project Manager, said: "Contrary to the claims of the RSPB, Strathy South will actually help restore over 1,000 hectares of degraded peatland while the wind farm will have an impact on less than 100 hectares.
"The project therefore delivers a significant positive environmental gain for the Flow Country as well as offering a wide range of additional environmental and local economic benefits."
The project manager added: "We have discussed the proposals at length with RSPB, SNH and all stakeholders with a view to achieving the best outcome and we will continue to engage with RSPB in a pragmatic and scientific way should they be interested in doing so."