In November 2007 the British Trust for Ornithology in partnership with the Scottish Ornithologists' Club and Birdwatch Ireland started a four year winter and breeding season atlas project aimed at revising the distribution maps and population estimates from the 1981-84 Winter Atlas and the 1988-91 Breeding Atlas. The winter season will span the months of November to February inclusive and for most species the breeding season will be considered to extend from the start of April to the end of July, although breeding records for earlier and later nesting species will also be collected..
The methodology for the survey comprise two components: Roving Records and Timed Tetrad Visits.
The Roving Records method will aim to build complete species lists for each 10km square. During the breeding season additional behavioural data will be collected to assign possible, probable or confirmed breeding status on the basis of standard criteria.
The KOS project will use the same methodology, but will capture information at the tetrad (2km x 2km square) level. This will cover all the 1000+ tetrads which are included within the KOS recording area.
For Timed Tetrad Visits (TTVs) for the BTO Atlas, two visits will be made to a minimum of eight tetrads in each 10km square in each season. However, the KOS is attempting to carry out TTVs in each tetrad in the county. This is an ambitious target but should be achievable with the cooperation of KOS members. Each visit lasts at least one hour, preferably two hours. It is expected that during that time a representative sample of the available habitat will be covered. During these visits the emphasis will be on counting all birds observed, as this data will primarily be used to determine abundance. Fuller details of the Atlas methods can be found on the BTO Atlas website.