The monitoring of British breeding birds: a success story for conservation science?

For almost four decades the British Trust for Ornithology has monitored populations of the commoner 35-50% of species of British breeding birds. The monitoring involves surveillance of numbers, breeding output and survival rates across the whole of the United Kingdom. A formal alert system allows serious declines to be identified and brought to the attention not only of conservationists and those responsible for countryside policy but also the general public. Demographic modelling, the gathering of ancillary information and linked research programmes allow the causes of declines to be identified. The paper details the operation of the programme, illustrated by examples. The system has resulted in the widespread declines in farmland birds that occurred in the last quarter of the 20th century being brought to the attention of conservation scientists, campaigners, policy-makers, politicians and the public. From this (and from the associated understanding of the causes of the declines) have stemmed policies aimed at reducing the problems and a commitment by government to halt the declines. The success of the programme rests on scientifically rigorous design and analysis, on a partnership between volunteer birdwatchers (who do most of the fieldwork) and professional ecologists (responsible for design and analysis) and on effective interaction between scientists and policy makers.