The conflict between feeding and territorial defence in the great tit

Summary

A field experiment investigated whether feeding and territorial defence competed for time in the activity budget of territorial male great tits during the spring. Feeding tables were placed on the territories of five males. Five other territorial males also fed at these tables, while ten additional males had no access to any feeding tables. A standardised ‘intrusion’ using playback of territorial song and a stuffed mount of a male great tit was conducted on each of the twenty territories, and the response of the resident male measured. All of the males with access to a feeding table responded more vigorously to the intrusion than the males who received no extra food. These results are not attributable to the fact that males defended their territories more vigorously because of the addition of feeding tables, since males that gained extra food outside the boundaries of their own territories also defended more vigorously than birds with no access to a feeding table. The results support the conclusion that the provisioned males defended more vigorously because they could afford to take more time out from feeding.