Red-Throated Diver National Survey in Britain in 2006 - 5km square summary

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. The survey gives a complete census of the Northern Islands (Shetland and Orkney), of two Special Protection Areas (SPAs) in the Hebrides with Red-Throated Diver as a qualifying feature (Rum and Mointeach Scadabhaigh), and of a stratified sample of randomly selected 5km grid squares in the rest of the known breeding range. Of the randomly selected squares, 9.7% held unsuitable habitat. In most cases, 5km squares were surveyed twice between 15 May and 15 August. Grid squares with no suitable habitat were only surveyed once. Surveyors recorded the number of breeding and apparent non-breeding pairs on each loch, in addition to the number and size of any young. If eggs or chicks were observed, but either one adult or no adults were observed, it was assumed that a pair of Red-Throated Divers must be present, and thus were included as a breeding pair. It is estimated that an additional 12% of the adults recorded as non-breeding may have actually bred.
   
   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 of Britain and the Isle of Man. Core Area surveys: Shetland, Orkney, the Inner and Outer Hebrides and the northern Scottish mainland.

The grid references in this dataset correspond to the bottom left hand corner of the 5km survey square.