The Cairngorms National Park Authority has been accused of endangering one of Scotland's rarest birds by backing big housing schemes and promoting tourism.
Four-fifths of the UK's dwindling population of capercaillie live in the national park, but experts have said the birds are suffering because of escalating interference from residents and visitors.
According to Dr Robert Moss, a wildlife biologist who has made a lifelong study of capercaillie, the national park is "conflicted" on the issue and ignores the advice of its own ecologists.
Moss is the lead author of a new scientific study of three woodlands in the Cairngorms area showing that capercaillie are very vulnerable to human disturbance. The birds stayed hundreds of metres away from places where people entered the woodlands, and at least 70 metres from tracks though the woods.
The study, published in the journal Wildlife Biology, said that capercaillie avoid much larger areas where dogs often stray from tracks, and in the most disturbed woods retreat to centres of trackless boggy ground for refuge.
Capercaillie populations have declined from about 20,000 in the 1970s to fewer than 2000 now, partly because of increased human disturbance.
The bird has been identified by the national park as a species in need of "urgent conservation action" over the next five years.
But at the same time the park authority is backing plans for a series of housing schemes which conservationists have said will harm capercaillie. The biggest - for 1500 homes at An Camas Mòr, near Aviemore - was abandoned by its developer last week, though the landowner behind the plan claimed it would still go ahead.
Moss, who lives near Banchory, is concerned that capercaillie are in decline. He said: "The bird needs better refuges from disturbance, including fewer woodland tracks, a culture that encourages people and dogs to stay on tracks, careful management of off-track activities such as snowshoeing and orienteering, and rewetting ground previously drained for forestry."
Capercaillie were suffering because the national park was ignoring its own experts, Moss argued. "It would be nice if the conflicted national park could be persuaded to take the advice of its own ecologists seriously, but that is probably too much to ask."
He was backed by the Badenoch and Strathspey Conservation Group, which has been involved in a prolonged legal battle against the national park. Dr Gus Jones, the group's convener, said the housing developments will disturb capercaillie and damage its habitat.
Bird organisation RSPB Scotland also welcomed Moss's research, and called for dogs to be kept on leads and refuges to be created for capercaillie.
"The doomsday clock is already perilously close to midnight for the capercaillie," said Dr Pete Mayhew, a senior conservation manager with RSPB Scotland.
The national park's chief executive, Grant Moir, pointed out that the park was developing a management framework for capercaillie to address the issues highlighted by Moss.
Moir said: "The Cairngorms are, of course, also highly valued for their outdoor recreation opportunities in an economy driven by tourism, and we have a long-term need to provide the right kind of housing in the right place."
Capercaillie were "one of the big ongoing challenges in managing the park", he said, adding: "Dr Moss's work is already informing the way we are tackling this through habitat enhancement and managing the impacts of human disturbance."