Black grouse annual lek surveys in Argyll & Bute, 2002-2011

Quality Control

Method steps

1. Surveying known lek sites
   Lek surveys were undertaken in good visibility in dry and calm conditions following the methods of Hancock et al 1999. Two morning visits were made to each lek site wherever possible. One visit was undertaken in each half of the survey period, visit one between 21st March and 18th April and visit two between 19th April and 15th May. The maximum number of males at the lek site that occurred during the period one hour before and one hour after dawn were recorded. All males (whether displaying or not) were recorded. Birds displaying within 200m of a known lek were recorded as one lek. Single birds displaying within 500m of a known lek were recorded as one lek. Two or more birds that displayed over 200m from a known lek were record as separate leks. The maximum number of hens attending the lek were recorded. The 6 figure grid reference for the lek site (or 8 figure grid reference if known), the date of the survey and the survey start and finish time were recorded.
   
   Lek searches
   A route was planned for the survey target area to take the surveyor within 500m of all suitable habitat once. The route was walked in the early mornings and evenings in addition to early morning listening from a good vantage point overlooking suitable habitat to detect leks. All leks located outwith the standard method time (i.e. outwith dawn survey period) were revisited and surveyed using the standard method. All routes were recorded on a 1.25000 map and submitted with the lek survey form. In order to verify records and validate the dataset, the data have been mapped and thoroughly checked.