Black grouse national surveys

Quality Control

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

Method steps

1. 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.

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.