Bird Atlas 2007-2011: What is it? For the first time the BTO will be combining the results of breeding season and winter fieldwork into one national Atlas. Winter fieldwork started in the winter of 2007/2008 and lasted for four winters. Breeding season fieldwork took place in the summers of 2008 to 2011. There were two complementary field methods:

1. Roving Records. For national distribution maps to be comprehensive we need complete species lists for every 10-km square, in both winter and the breeding season. Roving Records are a means of submitting lists for grid squares, one-off records of hard-to-find species, and anything in between. They are also a means of accumulating evidence of breeding and providing records of nocturnal species. Everyone can take part by supplying Roving Records.
2. Timed Tetrad Visits. Timed Tetrad Visits (TTVs) are principally concerned with discovering broad patterns of relative abundance by counting birds for fixed periods in tetrads. Tetrads are 2km x 2km squares and are labelled A to Z within each 10-km square (click here for information on identifying tetrads). TTVs do not aim to produce a complete species list for the tetrad, but a sample of what one can find during a pair of visits in winter and/or the breeding season.

For full details of the national Atlas project, click here .

What is happening in Sussex? In Sussex, alongside the fieldwork for the national Atlas, the SOS has organised additional fieldwork with the aim of producing a detailed local atlas of distribution and abundance of all bird species. We have surveyed EVERY tetrad in Sussex, so that we can gather enough data to be able to produce maps showing the distribution of each species by tetrad across Sussex, and also the relative abundance of most species in the county. In all there are about 1000 tetrads to be surveyed across the county, and each tetrad has been surveyed twice during winter and twice during the breeding season, using the same methodology of TTVs as used for the national Atlas. In addition, as many Roving Records as possible have been collected by tetrad, in order to build up comprehensive species lists for every tetrad.

The SOS plans to publish the Atlas results in two ways: a CD and a new avifauna. For more details click here.