The project aims to boost black grouse numbers. Photo: Forestry Commission Scotland

Landowners have called in air support to help endangered black grouse in a project backed by a national park.

Six farms and estates around Callander used helicopters to spray herbicide on bracken to help boost numbers of the birds.

The Scottish Rural Development Programme provided a £720,000 grant to support the work of the Callander Black Grouse Project, which is backed by the Loch Lomond and The Trossachs National Park Authority.

The scheme will control more than 270ha (667 acres) of invasive bracken to improve the habitat for the moorland bird. Since 1999, populations around Callander have declined from about 50 adult males to around 15 in 2010.

Due to the difficult terrain, the helicopters were hired as the most effective way to apply herbicide to target the bracken.

Scott Nisbet, national park land management adviser said: “We were really pleased to help these six businesses source funding for this worthwhile project.

“One of the issues facing black grouse in this area is diminished moorland quality due to grazing pressure by livestock and wild deer.

“By removing areas of dense bracken avoided by grazing animals, we can increase the area of available ground, reducing overall grazing pressure. In this way, we hope to encourage the regeneration of moorland plant species like heather and blaeberry which are important sources of food for black grouse.

“Areas of sparse bracken will be retained to provide cover for the species that are adapted to use it, including woodland plants such as bluebells and certain species of butterflies.”

Simon Thorp, coordinator of the Bracken Control Group and director of Scotland’s Moorland Forum added: “The Callander Black Grouse Project is a good example of the importance of having the right tools at our disposal to undertake effective bracken control, not just for agricultural or forestry purposes, but also to achieve conservation objectives for priority habitats and species like heather moorland and black grouse.”

Controlling bracken is one of a number of methods being used to try to boost black grouse numbers around Callander. Other measures include grazing management, small-scale heather burning, predator control and marking fences to reduce the risk of birds flying into them.