READ ME FILE Created 2021-10-22 ############ Supplementary online material for the 5th Birds of Conservation Concern in the UK, Channel Islands and Isle of Man (BoCC5) and 2nd IUCN Red List assessment of extinction-risk of birds in Great Britain (GB_IUCN2) Andrew Stanbury*, Mark Eaton, Nicholas Aebischer, Dawn Balmer, Andy Brown, Andy Douse, Patrick Lindley, Neil McCulloch, David Noble and Ilka Win *corresponding author- Andrew Stanbury, RSPB Centre for Conservation Science, The Lodge, Sandy, Bedfordshire, United Kingdom, SG19 2DL; email:andrew.stanbury@rspb.org.uk BACKGROUND Birds of Conservation Concern (BoCC)is a well-established, well-respected process for identifying conservation priorities for UK birds, and uses quantitative assessments against standardised criteria to allocate species into one of three lists, ‘Red’, ‘Amber’ or ‘Green’, depending on their level of conservation concern. These reviews have a long history, with the first published in 1996. the International Union for Conservation of Nature Red List process (IUCN) purely assesses extinction risk. Unlike BoCC, this approach allows different taxonomic groups to be assessed on a more level playing field, using the same well-established, internationally recognised criteria. This allows changes in status to be tracked and the potential creation of multi-taxa indicators (e.g. Red List Index). It is also worth noting that the IUCN Red List process can used at different spatial scales. Here, we use the standard Red list categories, e.g., Critically Endangered, Endangered, Vulnerable, to assess of extinction risk for Great Britain, as this is the scale national assessments are undertaken. It is important to emphasise that BoCC and IUCN are two separate distinct assessment processes with differing aims. ARCHIVE This archive contains six supplementary files, relating to the above assessments, published in the journal British Birds in December 2021 (Stanbury et al. 2021): 1: BoCC5_GBIUCN2_supplementary_online_material.docx (created 2021-10-22) contains additional detailed information, not covered in the paper, on the processes used for both the BoCC5 and IUCN2, including species/race selection criteria, descriptions of assessment criteria, data sources and other methodological details. 2: SOM_Table_1_UK_BoCC5_species_results.xlsx (created 2021-10-22) contains species-level assessments for BOCC5. Each row represents a species/race, with the columns denoting whether they fulfil the various BoCC assessment criteria, as well as their final placement on either the BoCC5 Red, Amber or Green lists (Column J). Explanations of all criteria can be found in the Stanbury et al. (2021) and BoCC5_GBIUCN2_supplementary_online_material.docx. 3: SOM_Table_2_UK_BoCC5_race_results.xlsx (created 2021-10-22) contains race-level assessments for BOCC5. Each row represents a species/race, with the columns denoting whether they fulfil the various BoCC assessment criteria, as well as their final placement on either the BoCC5 Red, Amber or Green lists (Column J). Explanations of all criteria can be found in the Stanbury et al. (2021) and BoCC5_GBIUCN2_supplementary_online_material.docx. 4: SOM_Table_3_GB_IUCN2_species_results.xlsx (created 2021-10-22) contains species-level assessments for GB_IUCN2. Each row represents a species/race population, with the columns containing information relevant to the Regional IUCN Red List assessment, including generation length, qualifying criteria and final species/race threat status (Column R) with justifications for each stage of the Regional IUCN Red Listing process. Further explanations can be found in the Stanbury et al. (2021), BoCC5_GBIUCN2_supplementary_online_material.docx and IUCN (2019, 2012) 5: SOM_Table_4_GB_IUCN2_race_results.xlsx (created 2021-10-22) contains race-level assessments for GB_IUCN2. Each row represents a species/race population, with the columns containing information relevant to the Regional IUCN Red List assessment, including generation length, qualifying criteria and final species/race threat status (Column V) with justifications for each stage of the Regional IUCN Red Listing process. Further explanations can be found in the Stanbury et al. (2021), BoCC5_GBIUCN2_supplementary_online_material.docx and IUCN (2019, 2012) 6: Statement_of_voluntary_application_of_the_Code_of_Practice_for_Statistics.docx (created 2021-10-22) contains a statement about how the Birds of Conservation Concern Steering Group complied with the three main concepts, or pillars, of the UK government’s Code of Practice for Statistics. These files have no associated licenses or restrictions placed on them. References IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. IUCN, Gland, Switzerland & Cambridge, UK. IUCN. 2019. Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee. Downloadable from http://www.iucnredlist.org/documents/RedListGuidelines.pdf. Stanbury, A., Eaton, M., Aebischer, N., Balmer, D., Brown, A., Douse, A., Lindley, P., McCulloch, N., Noble, D., and Win I., 2021. The status of our bird populations: the 5th Birds of Conservation Concern in the UK, Channel Islands and Isle of Man and 2nd IUCN Red List assessments of extinction-risk for Great Britain. British Birds 114.