Cheshire and Wirral provides a wide range of habitats for birds, from the internationally important estuaries of the Dee and Mersey in the west to the high moors of the Peak District National Park in the east. During 2004 to 2007 more than 350 volunteers spent over 50,000 hours surveying each 2x2 km tetrad in Cheshire and Wirral, recording every bird species in the breeding season and in winter. This Atlas reveals dramatic changes since the county's first breeding bird Atlas of 1978-84, and also for the first time shows the detailed distribution of the wintering species. Lavishly illustrated with 300 pictures by local photographers and artists, this colour Atlas provides full accounts of 186 species, with briefer treatments for a further 31. More than 500 maps show the birds' distribution in the two seasons as well as the difference between seasons and the spectacular gains and losses in breeding status over the last twenty years. For the first time at county level, this Atlas also includes figures for the breeding populations of 65 of the most numerous species, 35 of which also feature abundance maps. In a further innovation for a project of this nature, observers recorded details of the birds' habitats, greatly increasing its overall conservation value.