Winter territory prospecting is associated with life-history stage but not activity in a passerine

Finding a high quality territory is essential for many animals to reproduce successfully. Despite its importance for fitness, we know little about the process of territory prospecting in wild birds, and whether individual traits and behaviours, such as personality, co-vary with territory prospecting. Here, we use long-term data from a wild, insular house sparrow Passer domesticus population to test three hypotheses about territory fidelity and prospecting: (1) House sparrows show high territory fidelity between years and also during winter. (2) Individuals will prospect for a breeding territory during their first winter whereas older, more experienced individuals will keep a territory from previous years and will, therefore, show no or reduced winter territory prospecting. (3) More active behavioural types will prospect more than less active behavioural types. We use data from four winters from automatically, daily recorded nest-box visits of 188 birds of known age. The number of nest-boxes that each individual visited within each winter was used as a proxy of winter territory prospecting. We show that house sparrows visit multiple nest-boxes during their first winter, whereas older individuals keep territories year-round and, potentially because of this, indeed show reduced winter territory prospecting. Activity was not associated with the number of nest-boxes visited. Further research is needed to investigate whether time of territory and mate acquisition differs among individuals and the possible effect on lifetime fitness.