| UPLANDS - CAPERCAILLIE
Causes and timing of low breeding success in capercaillie We have been counting and recording the breeding success of capercaillie since 1990. © GWCT
BACKGROUND Capercaillie in Scotland have seen a considerable decline in numbers and a range contraction since the 1970s. The latest national survey in 2015/16 concluded that they remain at a critically low level of around 1,000 birds, although many believe the number to be lower. Previous studies highlighted low breeding success as the proximate cause of declines.
We have been counting capercaillie annually in Scotland since 1990, using pointing dogs in August to find well-grown broods. In most years, we record a high proportion of hens without broods, but it is unclear at which stage of the breeding attempt failure has occurred. In partnership with Scottish Natural Heritage, Scottish Forestry, Forestry and Land Scotland and the Cairngorms National Park Authority, we embarked on a project to radio-tag well-grown hen chicks and monitor their breeding attempts in the following years. Between 2015 and 2017, we fitted six individuals with 13 gram radio transmitters with an expected battery life of 30 months. This allowed us to follow two hens over three breeding seasons and three hens over two breeding seasons (one hen died at
Pine martens were captured on camera removing eggs from capercaillie nests. © GWCT
70 | GAME & WILDLIFE REVIEW 2019
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