Thread by @simon_gillings

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

3 #BOUsci21 #Sesh1 // From these data we produce population trends for around 50% of UK breeding bird species. These account for over 95% of all individual birds in the UK, so BBS tells us a lot about our bird populations: bto.org/bbs-results #BTOscience

4 #BOUsci21 #Sesh1 // BBS was well designed from its inception, and through ongoing research and development, we have gradually added other features that teach us more about birds and the environment #BTOscience

5 #BOUsci21 #Sesh1 // Particularly important has been understanding how observers detect birds, how this changes through time, and what we need to do to ensure these subtle differences don’t artificially affect the trends we measure: bit.ly/BBS_timing #BTOscience

6 #BOUsci21 #Sesh1 // Ensuring coverage of different habitats across the UK is important because species’ trends vary geographically. Allowing single visits to selected upland squares is one way we are trying to reduce barriers to participation. #BTOscience

7 #BOUsci21 #Sesh1 // Lockdown during 2020 severely limited BBS fieldwork, especially early in the breeding season. The fact BBS has a robust sampling design made it easier to test where that had been violated and determine what we could safely do with data from 2020. #BTOscience

8 #BOUsci21 #Sesh1 // BBS provides much more than just large-scale population trends. We are increasingly producing maps of densities and looking at how trends vary between habitats. #BTOscience

9 #BOUsci21 #Sesh1 // BBS data are also a tremendous resource for assessing the causes of population change and testing solutions to them. For example, they are being used to develop tools for wildlife-friendly urban planning bit.ly/BBS_urbanplann… #BTOscience

10 #BOUsci21 #Sesh1 // BBS is a mature and well-established monitoring scheme but there are still many ways we want to develop it, , such as monitoring bird populations at more local scales: bit.ly/IntegratedMoni… #BTOscience

11 #BOUsci21 #Sesh1 // Success of BBS is down to the thousands of volunteers who take part, expertly organised by @harris_sjh, the BTO scientists who have developed it, direction from the BBS Steering Group, and the BTO IS team who make BBS Online. Thank you all #BTOscience