Black grouse national surveys

Royal Society for the Protection of Birds

Description

The male black grouse <I>Tetrao tetrix</I> population in Britain was surveyed in 1995/96 and 2005, in order to estimate population size. <br /><br />The surveys were based on counts of males displaying in the spring. In Wales and Staffordshire, the entire known population was surveyed in 1995. In northern England and Scotland in 1995/96 and 2005, and in Wales in 2005, a stratified random sample of 5 km squares from the breeding range was surveyed. As such the dataset covers around 10% of the UK population overall and does NOT contain all black grouse leks in Britain in the survey years; its aim was to produce a reliable population estimate. <br /><br />The 5 km squares where no black grouse were found will be included in the dataset when zero record display becomes available on the NBN. <br /><br />The 1995/96 survey estimated a population of 6510 males, the 2005 survey estimated population size to be 5078 males, a non-significant 22% decrease.<br /><br />

The surveys were organised by the Statutory Conservation Agencies and RSPB Breeding Bird Surveys (SCARABBS) scheme. The 1995/96 survey was funded by the RSPB, Scottish Natural Heritage, English Nature (now Natural England), the Joint Nature Conservation Committee and the Game Conservancy Trust (now the Game and Wildlife Conservation Trust). The Perthshire Black Grouse Study Group carried out a substantial part of the fieldwork. The 2005 survey was funded by the RSPB, the Countryside Council for Wales, Forestry Commission Scotland, the Game Conservancy Trust (now the Game and Wildlife Conservation Trust) and the Defra Rural Development Service (now part of Natural England), and organised with substantial help from the Central Scotland Black Grouse & Capercaillie Study Group, the Perthshire Black Grouse Study Group and the Strathspey Black Grouse Study Group.

Geographic Description

Scotland, northern England and Wales. Staffordshire is excluded from this NBN dataset due to the sensitivity of this isolated population to disturbance. Please note that, apart from the 1995 Welsh data, the dataset does NOT contain all leks of black grouse, because only a random subsample of the breeding range was surveyed.

Data quality

Data have been thoroughly checked for geographical and other errors. Please see the additional information sources for a detailed discussion of the survey methodology.

Methods

The survey covered the complete breeding range in Wales and Staffordshire in 1995, and random stratified 5 km squares selected from the breeding range in northern England and Scotland in both 1995/96 and 2005, and in Wales in 2005. In survey squares, surveyors walked within 500m of all suitable habitat and counted any displaying males at dawn. Often local knowledge from landowners was used to locate leks. At least one count was made of each lek, within one hour either side of dawn, and if possible in clear, still weather. Display sites were marked on a 1:25 000 map. Single displaying males, and groups of displaying males (leks), recorded more than 500m, and 200m apart, respectively, on the same or different visits, were considered as separate display sites. When leks were counted more than once, the peak count was used. Numbers of females observed have been included in the comments field, but these do not represent a population figure due to the usually fleeting and irregular nature of female visits to leks. Survey squares where no displaying male black grouse were found will be included in the dataset when zero record display becomes available on the NBN.

Citation

Please acknowledge SCARABBS (Statutory Conservation Agencies and RSPB Breeding Birds Scheme) and the Royal Society for the Protection of Birds, Scottish Natural Heritage, English Nature (now Natural England), the Joint Nature Conservation Committee, the Game Conservancy Trust (now the Game and Wildlife Conservation Trust) and the Perthshire Black Grouse Study Group in any use of the 1995/96 survey. Please acknowledge SCARABBS (Statutory Conservation Agencies and RSPB Breeding Birds Scheme) and the Royal Society for the Protection of Birds, the Countryside Council for Wales, Forestry Commission Scotland, the Game Conservancy Trust (now the Game and Wildlife Conservation Trust), the Defra Rural Development Service (now part of Natural England) the Central Scotland Black Grouse & Capercaillie Study Group, the Perthshire Black Grouse Study Group and the Strathspey Black Grouse Study Group, in any use of the 2005 survey data. See survey level metadata for further details of individuals and groups involved as volunteers.

Rights

CC-BY

Digitised records