Breeding Bird Survey (BBS)

The Breeding Bird Survey is the main scheme for monitoring the population changes of the UK’s common and widespread breeding birds.

Take part

BBS Online

Time, skill and support

You will undertake three site visits between April and June – a recce and two morning visits – along with data entry.

You need to be able to identify UK breeding birds by sight, song and call.

Our training courses can help you learn survey methodology or boost your bird identification skills.

Join this project

About the survey

The BTO/JNCC/RSPB Breeding Bird Survey (BBS) is the main scheme for monitoring the population changes of the UK’s common and widespread breeding birds, producing population trends for 118 bird and nine mammal species. BBS is able to monitor the population changes thanks to the dedication of almost 3,000 volunteers who survey their randomly selected 1-km square each spring.

The survey involves a recce visit and two early-morning spring visits to an allocated 1-km square. Volunteers count all the birds seen or heard while walking two 1-km lines across the square, and record any nest counts for colonial nesting birds in the square. Volunteers can optionally record mammals and visit their square later in the season to survey for butterflies. There is the option to return data on paper, via field recording forms or to submit data on BBS-Online.

Code of Conduct

Volunteers must follow BTO’s Code of Conduct. This code applies to our staff, our members, and volunteers, including surveyors and participants in the Ringing and Nest Record Schemes, (hereafter referred to collectively as ‘staff and supporters’). It applies to all BTO activities, whether online (including meetings and events, telephone, letter, and email) or offline (any face-to-face interaction). We've also written some guidance for volunteer fieldworkers, which will help beginners in particular.

Read the latest BBS report

The Breeding Bird Survey started in 1994, and a report is produced every year containing population changes and other results from the scheme.

The 2024 Breeding Bird Survey Report highlights the continuing decline of some farmland species and more recent declines of woodland birds, at least in England. In Scotland, there is a focus on upland birds, where an all-species indicator using BBS data shows a 20% decline since 1994. In Wales, there are mixed fortunes, with species like House Sparrow bucking the downward trend seen in England, whilst Curlew are in severe decline, as they are elsewhere in the UK. Some songbirds in Northern Ireland, such as Blackbird are doing comparatively well compared to the wider UK trend.

We thank nearly 3,000 skilled and dedicated volunteers who give their time to BBS and WBBS and make the monitoring of the UK’s breeding birds possible.