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  American Oystercatcher Study

Project Partners:

Gulf Coast Bird Observatory
Texas State University
Texas A&M Kingsville
University of Houston Clear Lake

Funding:

National Fish and Wildlife Foundation
ConocoPhillips
U.S. Fish and Wildlife Service Coastal Program
George and Mary Josephine Hamman Foundation
Jacob and Terese Hershey Foundation

Project Abstract:

GCBO has an ongoing research project to study the Western Gulf population of American Oystercatchers in Texas. This population is little studied and most knowledge is based on anecdotal evidence and assumptions. Based on an aerial survey from winter 2003, preliminary estimates of the Texas population show it to represent approximately 5% of the U.S. population, but little is known about how or if these birds interact with regional and/or international populations, what their reproductive parameters are, and what factors may be limiting their reproductive success. Without this knowledge, it is impossible to determine how Western Gulf Coast populations fit into the U.S. population as a whole or what conservation strategies are appropriate. We have completed two field seasons and were awarded another two-year grant so that we may learn more about this species in Texas. Our goals are to: 

  • Document the population status of the Western Gulf Coast American Oystercatcher population.
  • Document the breeding parameters of the Western Gulf Coast American Oystercatcher population.
  • Identify threats that may limit breeding success of individuals residing in the western limits of the species range.
  • Determine strategies to mitigate the identified threats.
  • Implement mitigation strategies to increase breeding success of American Oystercatchers along the Western Gulf Coast.

To help determine whether Texas oystercatchers are local in distribution or are part of larger regional or international populations, we have implemented a mark-resighting program by color banding birds recruiting and training volunteer observers to supplement staff effort for re-sighting data. This is also helping us determine whether pairs remain territorial throughout the year or only during the breeding season and how long individuals pairs stay together.

 

During our first two field seasons (2011, 2012, 2013), we monitored 220 nests in Dickinson Bay, Galveston Bay, West Galveston Bay, Bastrop Bay, Drum Bay, and East Matagorda Bay.  In 2012 and 2013 we also monitored 132 nests on the Central Coast. Nest monitoring is allowing us to assess reproductive success and survival, identify major nest predators, and determine the significance of human disturbance factors. We have documented egg predation by coyotes, opossum, and Laughing Gulls. We have monitored nests in two ways: (a) by deploying time-lapse, programmable infrared-capable, video cameras which continuously monitored nests for predators, and (b) by monitor nests using trained observers to record reproductive parameters and human disturbance variables. Nest monitoring was be performed using coordinated protocols from the American Oystercatcher Working Group.

 

In 2013 we undertook a stewardship program which included posting warning signs on nesting islands and giving public education seminars on the needs of bay island nesting birds. To date we have color banded 145 adults and 84 chicks.


Follow the 2014 field season on the GCBO Blog!

 

Texas Banding Scheme:

 

Upper left: maroon color band with white codes

Lower left: no band

Upper right: maroon color band with white codes

Lower right: USFWS metal band

 

Click here for a listing of all birds banded

 
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103 West Highway 332    Lake Jackson, TX 77566    |    Telephone 979-480-0999    |    Contact Us