1 #BOUsci21 #Sesh1 // If you’ve read somewhere that UK bird species are increasing or decreasing, chances are that information has come from the UK Breeding Bird Survey. @BBS_birds is run by BTO in partnership with JNCC and RSPB. #BTOscience 2 #BOUsci21 #Sesh1 // Since 1994, a loyal team of skilled volunteers has surveyed a stratified random sample that has grown to >4000 1-km squares. Twice each spring, they count birds along transects and assign them to distance bands to assess detectability #BTOscience