- Title
- An analysis of eastern Nearctic woodpecker drums
- Author
- Stark, Robert D
- Degree
- Doctor of Philosophy, Ohio State University,
Evolution, Ecology, and Organismal Biology, 2002.
- Advisor
- David Stetson
- Pages
- 351p.
- Abstract
- Woodpecker drums are a form of long-distance communication and have been implicated in a variety of territorial and reproductive behaviors. Drums are produced as a series of rapid strikes with the bird’s bill on a resonant surface, not associated with foraging or cavity excavation. The drums of all eastern Nearctic woodpecker species were analyzed to test for specificity in this signal. Results of a signal analysis indicated that drums were distinctive, but not species-specific. Separating species by biome (i.e., syntopy) increased classification rates over the concurrent analysis. There was no geographic variation found in the drums of North American species, except black-backed woodpeckers (Picoides arcticus). Significant correlations versus both phenology and phylogeny across species indicated that the overall phylogenic significance in woodpeckers versus drum variables were due to differences at the genus, not species, level. There were no correlations uncovered between phenology and drums. Analysis for individual recognition markers in drums noted cues encoded in the spacing of strikes and duration within signals. Further analysis indicated drums encode species, but not individual, information in woodpeckers. Next, I tested whether species markers were recognized by woodpeckers using behavioral response as the assay to reciprocal playbacks of conspecifics versus syntopic and allotopic heterospecific woodpecker drums. Results indicated species with divergent drums had similar behavioral responses to playbacks. However, some eastern species were equally responsive while syntopic, contrary to western species. Thus, behavioral responses through playbacks supported that eastern woodpecker drums were not species-specific. Further analysis on the influence of heterospecifics in syntopy indicated no significant effect on drums attributable their presence. Finally, I tested the variables responsible for species recognition in drums through modified signals. Results indicated that drum cadence and signal duration were important variables for discrimination. Further analysis indicated that a combination of drum parameters may be required to elicit a maximal behavioral response. Of the competing hypotheses for signal recognition in a complex acoustical environment, these results indicated support for the additive-redundant hypothesis.
- Subject Headings
- Biology, Zoology
- Keywords
- Behavior; communication; drums; Picidae; song; woodpecker.
Document number: osu1028842312.
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