Scottish Crossbill National Survey in the UK in 2008

Quality Control

These data have been gathered by trained field-workers and the data are of a high quality. These data have been mapped and checked for sensitivities and typographical/geographical errors.

Method steps

1. Sampling was based on 1 km grid squares, containing coniferous woodland at their centre; every fourth square was surveyed, resulting in 852 survey sites. Crossbills were lured to the sampling points by playing a Crossbill excitement call from a CD player. The responding birds were counted, and their calls recorded. No attempt was made to identify the Crossbill species in the field. Crossbill species were identified as Scottish Crossbill, Common Crossbill or Parrot Crossbill by playing back their calls, and identifying species-specific call-types. The species of crossbill at 63 locations could not be identified from the recordings; these records are present in this dataset as Loxia sp.
   
   In order to verify records and validate the dataset, the data have been mapped and thoroughly checked. Geographical checks have included comparing the distribution with that shown in the published paper and ensuring that records with the same area name are located close to each other.

National survey: Scotland

Data are reported at 1 km resolution, where the grid reference denotes the bottom left hand corner of the grid square.