Overview

Every year, volunteers across the UK take part in the BTO/RSPB/JNCC Breeding Bird Survey (BBS), recording breeding birds in randomly selected 1-km squares (stratified regionally by observer availability) to robustly monitor population trends of some UK bird species. However, the chances of randomly selected squares containing rarer bird species and the habitats of interest that only cover a small proportion of the landscape are low, limiting our ability to monitor population changes. 

The work reported here examines options for increasing coverage of rare species and of assemblages occupying certain habitats of interest within the BBS framework, by including additional strata based on habitat type. It also assesses the benefits and risks of including an additional stratum based on accessibility to increase volunteer uptake in large regions with low observer density and many inaccessible areas. Volunteer recruitment is often difficult in these regions because randomly selected unmonitored BBS squares may require long drives, difficult walks and over-night camping.