The Great Grey Owl Strix nebulosa-a bird of the northern taiga

Hildén, O., & Helo, P. (1981). The Great Grey Owl Strix nebulosa-a bird of the northern taiga. Ornis Fennica, 58(4), 159–166. Noudettu osoitteesta https://ornisfennica.journal.fi/article/view/133079