The Bird Observatories’ primary purpose is to conduct long-term monitoring of bird populations and migration.

Individual Observatories are located at prime migration points, where a daily census is taken and other standardised methods of data collection are used in a defined recording area.

An integral part of observatory work is bird ringing, undertaken within the national scheme which is licensed under the Wildlife and Countryside Act 1981 and co-ordinated by the British Trust for Ornithology.  This provides data for guiding conservation policies of such bodies as English Nature, the Countryside Council for Wales, Scottish Natural Heritage and their counterparts in Ireland.

The Observatories enable and encourage volunteers to participate in scientific studies of birds and the environment.  The results of these studies and more general information are made freely available to researchers and to the public who are welcome to visit Observatories.

The work of Bird Observatories is co-ordinated and promoted at a national level by the Bird Observatories Council, to which individual Observatories are accredited when they meet specified criteria relating to activities.