The Communication Behavior Of The Pigeon Guillemot Cepphus Columba.

The form and variability of the signals used by animals in communication are expected to reflect the type of information that the signals encode. Signals, or parts of signals, that encode identifying information (individual, sex, status) must necessarily be relatively invariant. In contrast, communication of labile information such as the probability of performing other behavior (attack, flee) requires a variable signal. The vocal behavior of the Pigeon Guillemot (Aves: Alcidae, Cepphus columba) is described in this thesis and variability in vocal signals is discussed in relation to two questions: (1) Do signals provide information about the signaler's intentions in agonistic situations? (2) Are there general rules which relate signal form to message content? Guillemot agonistic interactions often include a series of whistled notes, repeated about once per second, given by a resident territorial male and by intruding males. The series of whistles lasts up to 12 min (mean = 85 sec). The role asymmetry (territory owner vs. intruder) explains most of the variation in which bird attacks and which flies. Intruders change their vocalization prior to flight by giving notes of shorter duration and higher sound frequency. Longer notes of lower frequency correlate with an increased probability of attack, but it was not possible to predict attack with a logistic model relating vocal parameters to the probability of subsequent behavior applied to an independent set of data. Analysis of behavior sequences also corroborated this result: one display, the Neck-stretch, was followed by flight in 45% of its performances by intruders, yet no display consistently preceded owner attack. Within three of four structurally variable vocal display classes, higher sound frequency, and shorter single note or vocalization duration were associated with evidence of high arousal in the signaler. This general information referring to the probability of performing some behavior may supplement the information in contextual sources that may more narrowly define what the signaler is likely to do next.Ph.D.Biological SciencesZoologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/127628/2/8304556.pd