Over the past 30 years, the king rail (Rallus elegans) has purportedly declined precipitously throughout its range, with the most severe declines seen in the migratory populations. King rails, however, are considered a game species in Louisiana and Texas, thus, it is important to determine what proportion of king rails wintering there are migratory. This is complicated because there is no reliable method to distinguish between king and clapper rails and few studies have attempted to capture wintering rails. The objectives of this study were to: 1) Determine the best method for capturing wintering rails; 2) Determine if morphometric measurements could be used to identify and sex king and clapper rails; 3) Determine the ratio of resident to migrant king rails in southern Louisiana and Texas using stable isotope analysis of feathers. I captured 523 rails, including 187 tentatively identified king rails, 68 tentatively identified clapper rails, 107 Virginia rails, 123 sora, and 38 yellow rails. The effectiveness of capture techniques were: 1) drop-door traps with drift fencing - 0.0063 rails per trap hour, 2) capturing by hand or net from an airboat at night - 2.13 rails per hour, and 3) capturing by hand or net from an ATV at night - 1.80 rails per hour. Discriminate analysis of morphometric measurements revealed that wing, tarsus and culmen measurements could be used to differentiate between king and clapper rails. Multiple stable isotope analysis of rail feathers, äD, ä13C, ä15N, and ä34S, showed distinct differences among winter collected king rails and known migrants, but did not show differences between the winter collected king rails and residents. This indicates that most, if not all, of the winter collected king rails were resident to Louisiana and Texas. A linear relationship was seen between äDf values and estimated äDp values at the collection locations (r2 = 0.42). The fractionation factor that resulted from this analysis could be used to determine an approximate breeding location for the winter collected rails, and also indicated that most, 99%, of the winter collected king rails were resident to Louisiana and Texas.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-04052007-135919 |
| Date | 09 April 2007 |
| Creators | Perkins, Marie |
| Contributors | Brian Fry, Phillip Stouffer, Sammy King |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-04052007-135919/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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