Have a look at the fascinating new internet based Thames and Chiltern Bird Atlas, covering the counties of Hertfordshire, Bedfordshire, Berkshire, Buckinghamshire and Oxfordshire.

The website presents the results of the three tetrad based breeding bird distribution surveys carried out in Hertfordshire in 1967-73, 1988-92 and 2007-2012 and the similar surveys done in the other counties. This sets the Hertfordshire results in a wider setting, including the Chiltern Hills and the Thames Valley giving a fascinating insight into the distribution of our birds.

The Thames and Chiltern Bird Atlas brings to life projects which together provide information on changes in the distribution of the breeding birds of over 9000 square kilometres of inland southern England, the density of breeding and wintering birds and habitat information for the area.

Its aim is to provide a source of information for birdwatchers and naturalists interested in the wildlife of their area, a reference source for local policy makers assessing the species and sites whose conservation should be promoted and a source of information for scientists researching population changes and density and their relationship to habitats  

The area covered comprises 9276 sq km of inland southern England. From north to south it encompasses part of the southern Cotswolds, the vales of White Horse and Aylesbury, the chalk hills of the Chilterns and Berkshire Downs and valleys of the Thames and some of its southern tributaries. It includes substantial urban areas, such as Watford, Reading, Oxford, Luton and Milton Keynes; the outer metropolitan suburbs and a variety of habitat types. It is an area which has seen substantial changes in the 20th Century, in both rural and urban areas and these changes continue.

Our aim is to provide a source of information for birdwatchers and naturalists interested in the wildlife of the area, a reference source for local policy makers assessing the species and sites whose conservation should be promoted and a source of information for scientists researching population changes and density and their relationship to habitats.

The site enables users to compare the distribution between species and between different surveys. Habitat information derived from derived from 1km habitat mapping carried out by the Centre for Ecology and Hydrology has been used to create habitat comparison maps and overlays of habitat types to use with species and species comparison maps. As such it provides a unique opportunity to see changes over a period of 20 years, or 40 years in the case of Bedfordshire and Hertfordshire, at a much finer scale than the national 10km atlas, and to compare these to habitat data.

Some well-known national trends, like the retreat of some declining farmland species, such as Grey Partridge and Corn Bunting, can be tracked, as can the spread of species such as Buzzard, Red Kite and some of the recent arrivals like Cetti's Warbler and Little Egret. There are though other changes that can be investigated, such as the decline of species once regarded as successful colonisers of urban areas, like House Sparrow and Starling, or the differing trends amongst waders, with some little-known changes such as Curlews starting to breed on the Berkshire Downs despite losses in the valleys of the Upper Thames tributaries. There are many other such stories too be investigated, and hopefully the information presented here will inspire some visitors to the site to use the data to investigate further some of the factors that may be influencing these changes.

The website was designed and built by Chris Dee (Garganey Consulting) and funded by Herts Bird Club, Bedfordshire Bird Club, Berkshire Ornithological Club, Buckinghamshire Bird Club, Hertfordshire Natural History Society, Oxfordshire Ornithological Society and the Thames Valley Environmental Records Centre. We are grateful to all the field workers whose efforts produced these maps, to the BTO whose generous extension of the on-line facilities set up for the 2007-2012 national atlas was an enormous help in realising the most recent surveys.

Contact Alan Gardiner at birdrecorder@hnhs.org for more information.