RSPB Big Garden Birdwatch winter sightings in the UK in 2009

Quality Control

The public recorded the species sightings in this dataset. Although the level of misidentified records may be higher than in datasets collected by trained field-workers, this is mitigated by the large sample size.

These data have been mapped and checked for sensitivities and typographical/geographical errors.

Method steps

1. Volunteer members of the public sat and watched birds for one hour during the last weekend of January, and counted the highest number of each bird species seen at any one time (not counting birds flying over). Volunteers were provided with a counting sheet to tally the numbers of birds, and pictures of the most common birds seen in gardens. Data were submitted to the RSPB online or on a form, which could be returned by post.
   
   In order to verify records and validate the dataset, the data have been mapped and checked. The distribution of the species has been approximately checked using species-specific filters to remove anomalously high counts and reports well outside the expected range. The level of misidentified records may be higher than in datasets collected by trained field-workers but this is mitigated by the large sample size.

The survey coverage is UK-wide. Grid references were generated from the central points of full postcodes. Within this dataset, there may be some bias towards the more populated areas of the UK.