BBS annual reports
The BBS started in 1994, and a report is produced every year containing population changes and other results from the scheme. Annual reports for every year back to 1994 can be viewed and downloaded.
BBS population trends
Bird population trends are published annually, and results from the most recent year are shown here.
Combined results from a number of BTO schemes, including joint CBC/BBS trends, can be found in the BirdTrends Report. Trends published in previous years can be found by downloading the relevant annual report from the BBS publications page.
Maps of population density and trends
Maps showing both bird density estimates and population change for 49 common bird species, modelled using BBS data.
Country, region and county species summaries
Annual numbers of species recorded, and number of BBS squares per species, by country (England, Scotland, Wales and Northern Ireland), by English Region, and by county. These lists are updated annually.
The latest mammal population trends produced using BBS data, and counts of mammals recorded on BBS squares in the most recent year.
Our volunteers: the beating heart of BTO data
Head and Principal Ecologist, David Noble, shares why volunteer-collected data are so important for an organisation like BTO.
BTO Conference 2020
The 2020 BTO Conference is available to view online. Catch up on a wealth of interesting talks and panels celebrating the efforts of BTO volunteers and members.