This is the fourth comprehensive assessment of the population status of all wild bird species in Europe. It identifies Species of European Conservation Concern (SPECs) so that action can be taken to improve their status. Species are categorised according to their global extinction risk, the size and trend of their European population and range, and Europe’s global responsibility for them. Of the 546 species assessed, 207 (38%) are SPECs: 74 (14%) of global concern (SPEC 1); 32 (6%) of European concern and concentrated in Europe (SPEC 2); and 101 (18%) of European concern but not concentrated in Europe (SPEC 3). The proportion of SPECs has remained similar (38–43%) across all four assessments since 1994, but the number of SPEC 1 species of global concern has trebled. The 44 species assessed as Non-SPECs in the third assessment (2017) but as SPECs here include multiple waders, raptors and passerines that breed in arctic, boreal or alpine regions, highlighting the growing importance of northern Europe and mountain ecosystems for bird conservation. Conversely, the 62 species assessed as SPECs in 2017 but as Non-SPECs here include various large waterbirds and raptors that are recovering due to conservation action. Since 1994, the number of specially protected species (listed on Annex I of the EU Birds Directive) qualifying as SPECs has fallen by 33%, while the number of huntable (Annex II) species qualifying as SPECs has risen by 56%. The broad patterns identified previously remain evident: 100 species have been classified as SPECs in all four assessments, including numerous farmland and steppe birds, ducks, waders, raptors, seabirds and long-distance migrants. Many of their populations are heavily depleted or continue to decline and/or contract in range. Europe still holds 3.4–5.4 billion breeding birds, but more action to halt and reverse losses is needed.