In late 2021, H5N1 highly pathogenic influenza A virus (HPIAV) clade 2.3.4.4b was detected in North American black vultures (BLVU). This study aimed to characterize the temporal IAV antibody dynamics in BLVU. Serum was collected from BLVU in Southeastern Pennsylvania in 2016 (pre-outbreak; n=51), 2023 (< 1-year post-outbreak; n=93), and 2024 (1-2 years post-outbreak; n=152). Results confirm long-term persistence of antibodies to H5N1 HPIAV in BLVU, requiring further immunologic significance research.