DALE, S. Relative magnitude of two Northern Hawk-Owl (Surnia ulula) irruptions to southern Norway: comparison of citizen data and survey data. Ornis Norvegica, [S. l.], v. 45, p. 1–9, 2022. DOI: 10.15845/on.v45i0.3425. Disponível em: https://boap.uib.no/index.php/ornis/article/view/3425. Acesso em: 25 apr. 2024.