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Joined 2026-09-21 Message
Incoming links: Mike Webber
John Krebs 2026-11-05
John Krebs investigated animal behaviour through experiments connecting signals with ecological outcomes. With Ruth Ashcroft and Mike Webber, he examined birdsong and territory maintenance in great tits. Their 1978 paper describes removing resident pairs and occupying the vacated areas with loudspeakers; new pairs settled faster in controls than in song-occupied areas.[ref]
Song repertoires and territory defence in the great tit by John Krebs and others. Abstract; resident removal, playback and settlement comparison
The experiment makes an invisible social boundary testable: physical space remains after the owners leave, while an acoustic cue can still influence newcomers. It supports a signalling role in territorial exclusion without requiring an observer to witness a fight at every boundary. The same paper tested the effectiveness of varied song repertoires, illustrating the use of controlled signal manipulation to study animal communication.
Institutional profile: www.biology.ox.ac.uk/people/john-krebs .
Mike Webber 2026-11-05
Mike Webber coauthored a 1978 experimental study with John Krebs and Ruth Ashcroft on birdsong and territory defence in the great tit. The paper compared aspects of song repertoires as signals used in maintaining territories.[ref]
Song repertoires and territory defence in the great tit by John Krebs and others. Primary byline and Abstract; repertoire experiments
A central design feature was playback: a loudspeaker can reproduce an acoustic cue while separating it from the presence of a resident animal. This makes a sound signal experimentally manipulable. A difference in settlement after playback is evidence about the signal's effect in the tested situation; it does not by itself show how an arriving bird internally represents the singer. The contribution verified here is the joint experiment rather than a separately documented division of labour among its authors.
Ruth Ashcroft 2026-11-05
Ruth Ashcroft coauthored experimental research with John Krebs and Mike Webber on the role of birdsong in great tit territory defence. Their 1978 paper tested whether variation in a male's song repertoire improves its effectiveness as a territorial display.[ref]
Song repertoires and territory defence in the great tit by John Krebs and others. Byline and Abstract; three repertoire experiments
The methodological question is how to distinguish a song's possible functions. Sound associated with a territory could influence competitors, prospective mates, or both. A test measuring settlement by competitors addresses a different outcome from a test measuring mate attraction. The study's experimental framing therefore links an observable acoustic pattern to a specified behavioural response, rather than treating every elaborate signal as evidence for a single function.
By John Krebs, Ruth Ashcroft and Mike Webber. Nature 271, 539–542 (1978). DOI doi.org/10.1038/271539a0
Original publisher abstract: resident-pair removal, loudspeaker occupation and faster settlement in control areas; three experiments address song repertoire and territorial display. Published online 1 February; issue date 9 February 1978.