Post‐fledging family space use in blue and great tit: similarities and species‐specific behaviours

Abstract

In birds, parental escorting of dependent young to feeding areas outside the breeding territory is a commonly observed, yet poorly documented phenomenon. Using radio‐tracking, we provide a detailed description of the post‐fledging movements of 12 blue tit Cyanistes caeruleus families and compare these observations with a much larger dataset of the closely related great tit Parus major collected over several years in the same study area. The proportion of families making excursions outside woodlots was similar in both species (± 50%), but the spatial extent of these movements tended to be larger in blue tits (mean ± SE: 1100 m ± 265, range: 643–2374, n = 6) as compared to great tits (mean ± SE: 666 m ± 42, range: 245–1898, n = 64). Blue tit families foraged significantly more in oak habitat within woodlots, independently of excursion behaviour, whereas great tits undertaking excursions shifted their range use towards more variable habitat outside woodlots. The observed excursions of blue tits appeared multiple‐day or permanent shifts of the family range, and not daily excursions as most frequently observed in great tits. Although family movements in both species may be largely driven by common underlying factors, our results also points toward species‐specific difference in spatial behaviour which may be linked with foraging specializations and post‐fledging territory fidelity.