Hogstad, Olav. 2015. “Social Behaviour in the Non-Breeding Season in Great Tits Parus Major and Willow Tits Poecile Montanus: Differences in Juvenile Birds’ Route to Territorial Ownership, and Pair-Bond Stability and Mate Protection in Adults”. Ornis Norvegica 38 (May), 1-8. https://doi.org/10.15845/on.v38i0.800.