Song-type matching between neighbouring song sparrows.
In our study population, neighbouring song sparrows typically share two or more of their 6-10 song types. In an earlier experiment, we found that established neighbours typically reply to playback of neighbour-shared song with a different song they share with that neighbour ('repertoire matching'), rather than with the same song ('type matching') or with a nonshared song. In the present experiment, we considered the hypothesis that type matching is a threat or warning signal (Krebs et al. 1981, Animal Behaviour, 29, 918-923). We tested the specific prediction that a bird is more likely to type-match early in the breeding season when territory boundaries are new and still unstable, and more likely to repertoire-match later in the season, once those boundaries have become well established. Birds were played a shared song of a new neighbour once early (April) and again late (June) in the breeding season. As predicted, early in the season birds usually type-matched the playback (73% of the trials) but late in the season they type-matched only rarely (18%); birds never replied (early or late) with a nonshared song type. Copyright 2000 The Association for the Study of Animal Behaviour.
Beecher
MD
Animal Behavior Program, Departments of Psychology and Zoology, University of Washington
Campbell
SE
Burt
JM
Hill
CE
Nordby
JC