The Breeding Bird Survey (BBS) provides national population trends for over 100 species. Here we show how BBS distance-band counts can be used to map the abundance and trends of 49 bird species across the UK, using statistical models. Read how maps of population density and trends are produced, in work carried out by Dario Massimino and colleagues.
Density
The average population density during 2007–2009. These maps show where a species is most common.
- Darker colours correspond to higher density.
Change
The change in population density between 1994–1996 and 2007–2009.
- Increases are shown in blue and declines in red.
- Dot size indicates average density.
Explore the BBS maps
Select a species from the drop-down list. You can then select a map to enlarge it.
"Health Warnings"
Uncertainty
The statistical models used to create these maps are less reliable in areas where few BBS squares are surveyed. The darker areas on the map show where our estimates are less certain. These are concentrated in Northern Ireland, some islands, northern Scotland, and upland areas across the UK. Please consider this when interpreting the maps.
- Consider taking up a BBS square to help reduce this uncertainty.
Date range
The maps use data to 2009, so will not represent recent population changes (e.g. declines caused by cold winters).
Species-specific uncertainty
Some species were better modelled than others, with estimates for Kestrel and Cuckoo having the greatest uncertainty.
How do BBS maps compare to Atlas maps?
The Bird Atlas 2007-11 produced maps of occurrence and relative abundance for a complete set of breeding and wintering birds. Although only possible for a subset of common and widespread species, these BBS maps provide additional information about actual breeding density by using distance-band data collected by surveyors.