Up-to-date atlases of bird distribution are essential for birders wishing to locate their local or nationally scarce birds, and enable them to contribute their own sightings for the biological record.
74 : The Atlas of Breeding Birds in Britain and Ireland
1976
Up-to-date atlases of bird distribution are essential for birders wishing to locate their local or nationally scarce birds, and enable them to contribute their own sightings for the biological record.
One of the British Trust for Ornithology’s greatest achievements has been the collation of many millions of observations of common and regular British bird species over decades, so that a true picture of their distribution, movements and changes in populations can be established.
Key to the ongoing accumulation of this data, and a prime motivator too, was the compilation of The Atlas of Breeding Birds in Britain and Ireland (1976) and its follow-ups and spin-offs (now including the up-to-date Bird Atlas 2007-2011). Compiled in association with the Irish Wildbird Conservancy (now BirdWatch Ireland), the original mighty tome mapped out the breeding distribution of all the birds of the British Isles, recruiting volunteers from the birding public to census birds at sites using rigid 10-kilometre squares (subdivided into 25 ‘tetrads’ which are 2x2km squares), giving the observations a real scientific rigour and meaning.
The project followed in the wake of the innovatory Atlas of the Breeding Birds in the West Midlands by J Lord and D J Munns (1970), the first book to use the technique, as well as Perring and Walter’s Atlas of the British Flora (1960). Forming an Atlas Working Group in 1967, the BTO was able to draft in almost 15,000 birdwatchers to submit their records over the period 1968-72.
The format of the first Atlas, as it simply became known, used 250 maps, with three dots in decreasing size variously representing the confirmed, probable or possible breeding respectively of all 218 species of British breeding birds. It became an essential purchase for all birders interested in their country’s avifauna, as well as an invaluable ornithological and conservation tool.
Logically enough, The Atlas of Wintering Birds in Britain and Ireland (Lack 1986) followed a decade later, covering the winters of 1981 to 1984, and the second breeding bird atlas was published in 1994, covering the period 1988-91. This last work used exactly the same methods to enable changes to be compared directly in scientific papers and within the book itself.
Another major variation on the theme was The Migration Atlas in 2002, a substantial addition to the literature on the subject, this time using modified techniques to plot bird movements generated through a huge volume of national and international ringing recoveries. The most recent and ambitious atlas project yet develops the formula still further, covering both the breeding and wintering distributions of the national avifauna for the period 2007-11. Better resourced and with greater support from birders, it utilised the services of 40,000 ‘volunteer recorders’ to map over 216 million birds through 182,230 timed tetrad visits, 5.3 million ‘roving records’ and another 4.5 million records submitted through the BTO’s online BirdTrack scheme.
Such an efficacious format has caught on worldwide, with similar methods being used in virtually every county, state, province, region and country with a bird club, ornithological society or bird conservation organisation.
Data gathering has only been sharpened by the online presence of the BTO’s BirdTrack website and its long-running American counterpart eBird, both of which have ambitiously expanded beyond their core national areas (see pages 188–189) to gather data worldwide.