Bird Atlas 2007–11 was a resounding success with over 216 million birds of 520 species and subspecies recorded from over 3,870 10-km squares during the four winters and four breeding seasons of fieldwork. The main results can be found in the book, Bird Atlas 2007–11: the breeding and wintering birds of Britain and Ireland (available from the BTO shop, but in these pages you can find additional resources.
Pattern and Change
Using the data on groups of species we can see patterns and changes in the avifaunas of Britain and Ireland over the last 40 years.
Full details of patterns of coverage and effort can be found in Chapter 5 of the Bird Atlas book but you can find a short overview here. See also monitoring progress for examples of how we gauged effort through the project in order to identify critical gaps in coverage.
Find out how we brought together different data sources to build comprehensive maps for all species in Britain and Ireland.
Many previous atlases have derived and published estimates of population size. In the UK and Ireland population estimates are now produced by other methods.