Banded Wren Song Communication
Song matching and repertoire matching among Banded Wrens
Banded Wrens, Thryothorus pleurostictus, are age-restricted learners with moderately-sized repertoires of discrete song types. Males copy whole song types from tutors and usually share a substantial fraction of their song-type repertoire with their neighbors.
Each Banded Wren has a song repertoire containing about 20 to 25 song types. They have very high levels of song-type sharing with their neighbors (60% to 90%). Banded Wren males are highly territorial and appear to countersing with each other extensively during aggressive interactions.
Left: A Banded Wren, Thryothorus pleurostictus, collecting twigs for its nest
Shared and non-shared song types are used strategically during territorial countersinging encounters. When one neighbor sings at the other, the second bird often replies in one of three ways:
1. He may reply with a different song type that they both sing. This is called repertoire matching, since they deliberately select reply song types that the other bird has in his repertoire, but not the exact same song type that the neighbor has just sung. Banded Wrens appear to treat repertoire matches as a non-threatening, but "directed" signal that indicates the intention to continue interacting.
2. Alternatively, he may reply with the same song type as the other singer, referred to as song-type matching. When birds song-type match, they appear to be threatening their opponent with an attack. A neighbor who is song-type matched must choose his reply carefully because if he continues to escalate, a fight will likely ensue.
3. Birds may also reply with a song type they do not share with that neighbor. Birds who sing these non-shared songs appear to be attempting to back down from a potential fight. Non-shared song types seem to be a de-escalation signal.
Neighbors who have already established a relationship may thus be able to use this extra step to de-escalate and avoid costly fights.
The figure below shows the partial repertoires of two "neighbor" Banded Wrens, named "O", and "Yoda", who share about 80% of their repertoires. Their shared song types are seen below in columns along side each other, as are examples of non-shared song types.
Click on each sound spectrogram to hear the song. Banded Wrens occasionally create compound songs, as "Yoda" has done in his first song, below. Why they do this is another of the questions under investigation.
|Songs of "O"||Songs of "Yoda"||Songs of "O"||Songs of "Yoda"|