Low flock coherence in mild winters leads to a lack of subordination costs in Bridled Titmouse foraging groups

Titmouse winter social behaviour has previously been studied in regions with severe winter weather. This paper reports on a study of the non‐breeding behaviour of the Bridled Titmouse Parus wollweberi in Southeastern Arizona. Bridled Titmice in larger foraging groups spent a greater proportion of their time in locations that were more exposed to predators but also more profitable in terms of prey capture rate. Flock coherence was low, with flock mates usually foraging in separate trees. Dominant and subordinate group members did not differ in their use of dangerous foraging sites. These results indicate that Bridled Titmice make an adaptive trade‐off in the use of foraging locations, using more profitable sites when predation risk is decreased through larger group size. Additionally, subordination appears to be less costly than in other tits studied previously. The warmer temperatures and longer days of this study, compared with similar studies, are likely to have strongly influenced the flock dynamics of the Bridled Titmouse.