This scientific report provides an overview of highly pathogenic avian influenza (HPAI) virus detections in poultry, captive birds, wild birds, and mammals from December 2023 to March 2024, as well as human cases due to avian influenza viruses up to March 12, 2024. The overall number of HPAI virus detections in birds was significantly lower compared to previous years, possibly due to flock immunity in wild bird species and reduced environmental contamination. Most HPAI outbreaks in poultry were primary outbreaks following the introduction of the virus by wild birds. Outside Europe, the majority of outbreaks in poultry were clustered in North America, while the spread of A(H5) to more naive wild bird populations on mainland Antarctica is a particular concern. For mammals, A(H5N5) was reported for the first time in Europe, and goat kids in the United States represented the first natural A(H5N1) infection in ruminants. As of March 12, 2024, five human HPAI A(H5N1) infections, including one death, have been reported in Cambodia, and two human infections with A(H5N6) and four with A(H9N2) have been reported in China, with one fatal case of co-infection with seasonal influenza A(H3N2) and A(H10N5). Human infections with avian influenza remain rare, and no sustained human-to-human transmission has been observed. The risk of infection with currently circulating HPAI H5 viruses in Europe remains low for the general population, but remains low to moderate for those occupationally or otherwise exposed to infected animals.This scientific report provides an overview of highly pathogenic avian influenza (HPAI) virus detections in poultry, captive birds, wild birds, and mammals from December 2023 to March 2024, as well as human cases due to avian influenza viruses up to March 12, 2024. The overall number of HPAI virus detections in birds was significantly lower compared to previous years, possibly due to flock immunity in wild bird species and reduced environmental contamination. Most HPAI outbreaks in poultry were primary outbreaks following the introduction of the virus by wild birds. Outside Europe, the majority of outbreaks in poultry were clustered in North America, while the spread of A(H5) to more naive wild bird populations on mainland Antarctica is a particular concern. For mammals, A(H5N5) was reported for the first time in Europe, and goat kids in the United States represented the first natural A(H5N1) infection in ruminants. As of March 12, 2024, five human HPAI A(H5N1) infections, including one death, have been reported in Cambodia, and two human infections with A(H5N6) and four with A(H9N2) have been reported in China, with one fatal case of co-infection with seasonal influenza A(H3N2) and A(H10N5). Human infections with avian influenza remain rare, and no sustained human-to-human transmission has been observed. The risk of infection with currently circulating HPAI H5 viruses in Europe remains low for the general population, but remains low to moderate for those occupationally or otherwise exposed to infected animals.