British Trust for Ornithology

Birds have been ringed in Britain and Ireland for nearly a hundred years and it still reveals new facts about migration routes and wintering areas.

The primary focus of the BTO's ringing schemes is now the monitoring of bird populations, to provide information on how many young birds leave the nest and survive to become adults, as well as how many adults survive the stresses of breeding, migration and severe weather.

The Constant Effort Sites (CES) scheme provides information on population size, breeding success and survival of bird species living in scrub and wetland habitats.

Ringing revealed that declines in the number of Sedge Warblers breeding in Britain and Ireland was linked to lower levels of rainfall in their African wintering quarters; whilst the recent dramatic decline in the numbers of Song Thrushes was found to relate to a reduction in the survival rate of young birds.

In 1947, the institute became part of a new department of Zoological Field Studies at the University of Oxford, and the BTO again concentrated on a programme of volunteer-based surveys.

In December 1962, at the behest of Tony Norris, the BTO purchased Beech Grove, a large Victorian house in Tring, Hertfordshire, relocating there from Oxford, along with their Ringing Office, which had been at the British Museum.

In April 1991, the BTO moved to The Nunnery, Thetford, Norfolk, a large property lying between the A134 and the River Little Ouse, which had been donated to them.

The trust awards the Bernard Tucker Medal for services to ornithology, named in memory of Bernard Tucker, the first secretary, and the Dilys Breese Medal[8] in honour of Dilys Breese[9] and several Marsh Awards for Ornithology.

[10] BirdTrack is an online citizen science website, operated by the BTO on behalf of a partnership of the BTO, the RSPB, BirdWatch Ireland, the Scottish Ornithologists' Club and the Welsh Ornithological Society (Welsh: Cymdeithas Adaryddol Cymru).