What data are available

BTO is widely respected for its independence and sound science, consequently our survey results are frequently used by conservation groups, government agencies, planners, ecologists, industrialists, environmental consultants and scientific researchers. The BTO encourages the use of its data.

If you wish to obtain data from one or more surveys please go to the Data Requests page.

Data can be supplied from all our surveys, but specific information on the most commonly requested datasets is detailed below.  Further information on survey are available on relevant pages, whether currently active surveys or completed historical surveys.

Most data are available as computer files although data from some of the older surveys and maps arising from such as the Common Birds Census are only available on paper and these normally can only be consulted when visiting The Nunnery in Thetford.

ATLASES OF BIRD DISTRIBUTION (all species)

Previous BTO/BirdWatch Ireland/SOC Atlases have been THE source of information on the distribution and abundance of British and Irish birds. Prior to Bird Atlas 2007–11, three atlases had been produced:

Atlas of Breeding Birds in Britain and Ireland: 1988-1

A species list of birds recorded is available for all 10-km squares containing land in the UK and Ireland and whether each species definitely or probably bred or whether it possibly bred in each during the survey period.
Species lists are also available for sampled tetrads.  (At least eight tetrads (2 x 2 km squares) in each 10-km square were sampled for a fixed 1 or 2 hours to obtain an estimate of the relative abundance in that 10-km square.  Note that these are not complete species lists for the tetrad as it is only those species recorded in the sample period.)

Atlas of Wintering Birds in Britain and Ireland: 1981/82 - 1983/84

A species list of birds recorded is available for almost all 10-km squares in the UK and Ireland.  In addition a figure for the relative abundance of each can be added, either the maximum count recorded in a day, or simplified to one of three levels of relative abundance.  Within a species these figures are comparable but they are not comparable between species.
There are no data available at a finer resolution than 10-km squares.

Atlas of Breeding Birds in Britain and Ireland: 1968-1972

A species list of birds recorded is available for all 10-km squares containing land in the UK and Ireland and whether each species definitely, probably or possibly bred in each during the survey period.

Bird Atlas 2007-2011

This survey covered all 10-km squares in the UK and Ireland and in both winter and the breeding season. Fieldwork was completed following the breeding season of 2011, and the data was analysed and published in 2014.

A species list of birds recorded in winter and the breeding season, together with a figure for relative abundance in each, and whether each definitely, probably or possibly bred, will be available for each 10-km square in all of UK and Ireland.  Species lists and some counts made will be available for sampled tetrads.

The Migration Atlas

See below under Ringing.

Breeding and wintering bird distributions in Britain and Ireland from citizen science bird atlases

Dataset that accompanies the publication of the same title.

These large citizen science surveys of bird distributions (atlases) in Britain and Ireland quantified breeding bird distributions on a 20-year cycle and wintering bird distributions on a c.30-yr cycle. These were used to generate spatially referenced information on apparent changes in bird distributions over c.40 years.

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

• Main type of variable contained: Detection of breeding and wintering bird species in grid squares during five periods, and changes in detection between periods.
• Spatial location and grain: 10-km grid squares (10km × 10km) containing land throughout Britain, Ireland, the Isle of Man, and the Channel Islands. The majority of data are at 10-km resolution but data for rare species are summarised at 20-km or 50-km resolution to protect sensitive locations.
• Time period and grain: The data represent summarised detection information derived from fieldwork during five periods: the breeding seasons 1968–72, 1988–91 and 2008–11, and the winters 1981/82–83/84 and 2007/08–2010/11.
• Major taxa and level of measurement: Birds, their distribution derived from citizen science surveys.
• Results: The combined distribution dataset contains 1,410,938 records detailing detections of 465 bird species in 3880 grid cells in different periods. The combined distribution change dataset contains 1,297,791 records describing stability, apparent colonisation or apparent extinction of individual species in grid squares between pairs of atlases spanning up to c.40 years. 
• Software format: Data are supplied as comma-separated text files. 

Breeding Bird Surveys (many species)

BTO/JNCC/RSPB Breeding Bird Survey (BBS): 1994 onwards

The count of each species recorded is available from nearly 3,500 randomly selected 1-km squares throughout the UK (earlier years have rather fewer samples) for each year the square was surveyed (one or more of 1994-present).

Waterways Breeding Bird Survey (WBBS): 1998 onwards

The count of each species recorded is available from about 500 randomly selected stretches of waterway throughout the UK (earlier years have rather fewer samples) divided into 500m lengths and for each year the stretch was surveyed (one or more of 1998-present).  (Note that some stretches are the same as WBS stretches.)

Common Birds Census (CBC): 1961-2000

Annual summary sheets can be supplied providing a list of the species and the number of territories of each recorded in each year the plot was surveyed.  About 250 plots were sampled each year mostly in farmland or woodland.  Maps showing where within the plots the birds were recorded and the habitat details for each plot can be consulted at the BTO headquarters in Thetford.

Waterways Bird Survey (WBS): 1974-2007

Data are available in the same format and on the same basis as for the Common Birds Census but for the birds along stretches of waterway.

Nest Record Scheme: 1939 onwards

Data are available on individual nest sites, their contents and such derived variables as clutch size, brood size and breeding success of many species of British breeding birds.

ALL-YEAR ROUND SURVEYS (many species)

Wetland Bird Survey (WeBS): 1965 onwards primarily in winter months

Counts of waterbirds, especially of wildfowl and waders, are available from Core Counts and Low Tide Counts.  Core Counts (around 2,500 sites are covered at least once each year) are conducted monthly at both coastal (normally at high tide) and inland wetlands throughout the UK.  Counts are normally on pre-selected dates, and concentrate on the winter period.  Low Tide Counts are conducted at most large estuaries in at least one winter every six years, with up to four counts being made through the period November - February.  The exposed substrate at low tide is divided into small count areas (sectors) enabling the distribution of feeding and roosting birds to be determined in finer detail.

BirdTrack: 2004 onwards

This online scheme allows the recording of birdwatching visits to sites and produces information on distribution and movements.  Summaries of records for particular species or particular places are available.

Garden BirdWatch (GBW): 1995 onwards

The numbers of birds of each species visiting about 12000 gardens report weekly.  Summary data on numbers are available -- see http://www.bto.org/volunteer-surveys/gbw/results for some example results.

Ringing -- recoveries, survival, causes of death, biometrics, moult: 1909 onwards

Data on the movements of individual birds are available, and a summary of the results is in The Migration Atlas.  Data on survival, causes of death, biometrics and moult are also available.

SINGLE SPECIES AND SPECIAL SURVEYS

Heronries Census: 1928 onwards

Counts of occupied nests are available from over 75% of UK heronries each year -- some have been visited every year for many years.  Periodic more complete surveys have been carried out.

Single Species and Special Surveys:  each of 1-2 seasons' duration

Data are available for several special surveys, often of single individual species.  Most commonly these comprise details of numbers of birds on specific sites (which may be sample squares of the National Grid) and of habitat use.

Recent surveys have included:

Ringed and Little Ringed Plovers in 2007

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