Pakkala, Timo, Juha Tiainen, Heikki Pakkala, Markus Piha, and Jari Kouki. “Nest Tree Characteristics of Grey-Headed Woodpeckers (Picus Canus) in Boreal Forests”. Ornis Fennica 97, no. 3 (September 30, 2020): 89–100. Accessed November 21, 2024. https://ornisfennica.journal.fi/article/view/133969.