Avian Data Bases and their use in Environmental Assessment

The databases of the British Trust for Ornithology that can be used in environmental assessment are described. The most important ongoing surveys from this viewpoint are as follows: the Ringing Scheme which gives information on annual mortality, the Nest Record Card Scheme which provides data on reproductive success, the Common Birds Census which gives an index of population, the Constant Effort Sites which monitors productivity and survival and the Breeding Bird Survey which complements and is replacing the Common Birds Census. The use of these databases in unravelling the effects of intensive agriculture on avian populations is discussed. The use of these databases to monitor global warming is also considered.