Home > Research > Summary of BTO Research > Bird Distributions

8. BIRD DISTRIBUTIONS

8.1 Atlases

The objectives of BTO atlases are to:

1.	describe the distribution of birds throughout Britain and Ireland, publishing the results in book form.

2.	make the distributional information available to conservation agencies for the purposes of site protection and development of regional conservation strategies.

3.	use the information for research purposes, especially to understand the factors determining bird distributions and patterns of biodiversity.

Three British atlases have been produced by the BTO (see reference list):

1.	Breeding Atlas. Surveyed 1968-72. Distribution, as possible, probable, or confirmed breeding, on 10x10 km square basis.

2.	Winter Atlas. Surveyed 1981-84. Distribution on semi-quantitative basis in 10x10 km squares.

3.	New Breeding Atlas. Surveyed 1988-91. Distribution on 10x10 km square basis (with incomplete coverage on 2x2 km basis), plus an objective measure of relative abundance in each 10x10 km square to provide contour maps of abundance. Full checks were made of potential regional biases in abundance measures. Changes in distribution since the first Breeding Atlas have been determined. The methods used in the New Atlas will allow unbiased comparisons to be made in future, to determine such changes more rigorously.

In addition, The EBCC Atlas of European Breeding Birds was published in 1997 (Hagemeijer & Blair, 1997). Distributional data of breeding birds in 50x50 km squares have been gathered for the whole of Europe (excluding most of European Russia but including the countries of the more westerly parts of the former USSR), with national estimates of population sizes and trends. Collation has been carried out largely by SOVON (the Dutch sister organisation to BTO) and the Netherlands Central Bureau of Statistics. The BTO has been closely involved in the production of the book and provided an editor.

8.2 Uses of the Atlas Data for Conservation and Research

Atlas data have a wide range of applications beyond their principal function of objective documentation of large-scale distribution patterns of species. These applications were recently reviewed by Donald & Fuller (1998) and include:

1.	Identification of areas of special conservation interest, including “richness hotspots”, and comparison of these with distribution of protected areas such as SSSIs.

2.	Documenting range and population changes. Where successive atlas surveys use comparable methodology, it is possible to identify areas where a species was retained between surveys, those where it was lost and those where it apparently colonised. Such data can be used to assess changes in species conservation status and hence help to set priorities for conservation.

3.	Providing a framework for survey design. Atlas data can be useful in designing surveys of species particularly when the species is uncommon or patchily distributed. The data can allow more efficient survey design by stratifying areas so that observer effort is directed mainly into areas within the species' range.

4.	Generating and testing hypotheses about causes of change. Comparison of environmental attributes of areas which have lost, retained or gained species may give insights into causes of population change and range contraction.

5.	Assessing bird-environment associations. Linking atlas data with environmental data has the potential to yield insights about causes of bird distribution at landscape and regional scales. Derived relationships may prove useful in predicting effects of future environmental changes on bird distributions.

Key References

Donald, P.F. & Fuller, R.J. (1998). Ornithological atlas data: a review of uses and limitations. Bird Study, 45: 129-145.

Gates, S., Gibbons, D.W., Lack, P.C. & Fuller, R.J. (1994). Declining farmland bird species: modelling geographical patterns of abundance in Britain. In: Large-Scale Ecology and Conservation Biology. 35th Symposium of the British Ecological Society (eds. P.J. Edwards, R. May & N.R. Webb), pp. 153-177. Blackwell Scientific Publications, Oxford.

Gibbons, D.W., Chapman, R. & Reid, J. (1993). The New Atlas of Breeding Birds in Britain and Ireland: 1988-91. T. & A.D. Poyser, London.

Gibbons, D.W. & Gates, S. (1994). Hypothesis testing with ornithological atlas data: two case studies. In: Bird Numbers 1992: Distribution, Monitoring and Ecological Aspects (eds. E.J.M. Hagemeijer & T.J. Verstrael), pp. 39-48. Statistics Netherlands, Voorburg/Heerlen & SOVON, Beek-Ubbergen.

Hagemeijer, E.J.M. & Blair, M.J. (eds) (1997). The EBCC Atlas of European Breeding Birds: Their Distribution and Abundance. T. & A.D. Poyser, London.

Lack, P.C. (1986). The Atlas of Wintering Birds in Britain and Ireland. T. & A.D. Poyser, Calton.

Sharrock, J.T.R. (1976). The Atlas of Breeding Birds in Britain and Ireland. T. & A.D. Poyser, Berkhamsted.

Williams, P., Gibbons, D.W., Margules, C., Rebelo, T., Humphries, C. & Pressey, R. (1996). A comparison of richness hotspots, rarity hotspots and complementary areas for conserving diversity of British Birds Conservation Biology, 10: 155-174.

Back to Research Summary Contents

© British Trust for Ornithology
BTO, The Nunnery, Thetford, Norfolk IP24 2PU
Tel: +44 (0)1842 750050 Fax: +44 (0)1842 750030 Email: info@bto.org
Registered Charity Number 216652. This page last updated: 27 February, 2006