Pakkala, Timo, Juha Tiainen, Markus Piha, and Jari Kouki. “Nest Tree Characteristics of the Old-Growth Specialist Three-Toed Woodpecker Picoides Tridactylus”. Ornis Fennica 95, no. 3 (September 30, 2018): 89–102. Accessed May 13, 2024. https://ornisfennica.journal.fi/article/view/133933.