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Zuberogoitia, I.; Zabalo, J.; Hidalgo, S.; Azkona, A.; Castillo, I.; Martínez, J. A.; Martínez, J. E. Seasonal Dynamics in Social Behaviour and Spacing Patterns of the Little Owl Athene Noctua. Ornis Fenn 2007, 84, 173–180.