Date of Graduation

1-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Biology (PhD)

Degree Level

Graduate

Department

Biological Sciences

Advisor

David G. Krementz

Committee Member

Daniel C. Magoulick

Second Committee Member

Fred M. Stephen

Third Committee Member

John D. Willson

Keywords

Biological sciences, Autumn migration, Fall migration, Raillidae, Species distribution, Stable isotopes, Wetland management, Wetlands

Abstract

Rails (Family: Rallidae) are among the least studied birds in North America, in large part due to their elusive nature. As a wetland-dependent species, understanding the timing of their migration and their habitat needs during migration is especially important since management needs to be timed to balance the needs of many species. I developed and verified a new distance sampling based nocturnal ATV spotlight survey because traditional call-broadcast surveys are not effective during autumn migration because of the drop off in call rate after the breeding season. These surveys allow us to ask point-level questions about what habitats rails select during migration and how it changes over time. Through these standardized surveys from 2012-2016 across 11 public properties in Missouri, USA, I documented the migratory timing and habitat use of migratory rails. Sora (Porzana carolina) have a wide migratory window, beginning in early August and continuing through the end of October with a peak in late September. Virginia Rail (Rallus limicola) and Yellow Rails (Coturnicops noveboracensis) have shorter migratory periods, from late September through the end of October. Rails, especially Sora, migrate earlier than waterfowl, which can create a mismatch of habitat needs. We performed a 3 year experiment to examine the response of Sora and waterfowl to early autumn wetland flooding.

Sora responded positively without a negative impact on waterfowl. I used monitoring data to create species distribution models to inform estimates of migratory connectivity for all three species using stable hydrogen isotopes. Sora and Yellow Rails were estimated to migrate generally north-south, with Virginia Rails coming from a wider east-west range. Through better understanding the migratory connectivity, timing and habitat use of rails in the autumn I provide a foundation to inform conservation and management of these fascinating and elusive birds. We provide a description of all variables used (Appendix II), GPS data of survey tracks and detection points (Appendix III), data sets of bird observation points, survey data, and vegetation information (Appendix IV), data sets of stable hydrogen isotope data (Appendix V), data sets of species distribution models (Appendix VI).

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