Zabala, J.; Zuberogoitia, I.; Martínez-Climent, J. A.; Martínez, J. E.; Azkona, A.; Hidalgo, S.; Iraeta, A. Occupancy and Abundance of Little Owl Athene Noctua in an Intensively Managed Forest Area in Biscay. Ornis Fenn 2006, 83, 97–107.