Effects of lek shape on reproductive behavior of Attwater's prairie chicken /
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| Other Authors: | , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | The relative importance of factors resulting in extinction of populations (demography, genetics, and catastrophes) is a matter of active debate. Genetic factors are likely to become important in small isolated populations of lekking species where few individuals contribute to subsequent generations. Attwater's prairie chicken (Tvmpanuchus cupido attwateri). a Iekking grouse, has become isolated in a few populations in south Texas. Lack of genetic variability may be slowing recovery of this endangered species. However, habitat alterations (e.g., roads) that influence leks to be linear rather than circular in shape have been hypothesized to increase reproductive variation. I investigated the effect of lek shape on the copulatory success of Attwater's prairie chickens and examined individual variation in the booming call of males relative to the males' copulatory success. A yearly spring population count examined the change in number of active leks. Grouse were observed at three leks of different shape (circular, intermediate, and linear) during morning displays of spring 1989 and 1990. Characteristics of sonogram records of the booming call were compared between four copulatory and three non-copulatory males. The first hypothesis tested was that more males copulated at linear than at circular leks. The number of males regularly attending did not differ significantly (P=0.22) across leks and years. Number of copulatory males was not statistically (P=0.35) different between the linear and the intermediate lek. Contrary to the prediction, an index of variation in male copulatory success was higher at the linear (3.8) than at the intermediate (3.3) and circular leks (2.2) in 1989. In 1990, few individuals attended the circular lek and the variance was lower at the linear (5.5) than at the intermediate lek (8.0) due to a significantly (P=0.03) lower number of copulations at the intermediate lek. A second hypothesis tested was that females were delayed in copulations at linear leks due to high inter-male aggression, leading to a lower nesting success because later nests suffer higher mortality. There was no evidence in 1989 that females at linear leks suffered delayed copulations. The third hypothesis tested was that booming calls of copulatory males differed from those of non-copulatory males. Total frequency of the booming call (F=30.26, P=0.0001) and frequency of the third note alone (F=25.34, P=0.0001) separated males that copulated from most males that did not copulate... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Wildlife and Fisheries Sciences." |
| Physical Description: | x, 75 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |