PS 10-115 - Movements and survival of juvenile Reddish Egrets along the Gulf Coast: The first year of life

Monday, August 8, 2011
Exhibit Hall 3, Austin Convention Center
Brock Geary1, M. Clay Green2, Daniel Reed3, Bart M. Ballard3 and Bill Howe4, (1)Department of Population and Conservation Biology, Texas State University - San Marcos, San Marcos, TX, (2)Biology, Texas State University, San Marcos, TX, (3)Texas A&M University - Kingsville, (4)U.S. Fish & Wildlife Service, Albuquerque, NM

Juvenile survival is considered to be a limiting factor in Reddish Egrets (Egretta rufescens), a plumage-dimorphic species whose conservation efforts are limited by a lack of life history information. In addition to providing basic information about the species, differences in movements between dark- and white-plumaged Reddish Egrets could point toward additional mechanisms that play a role in the maintenance of plumage dimorphism.  In this ongoing study, survival, dispersal and site fidelity of juvenile Reddish Egrets are measured using satellite telemetry. Data on 25 juveniles from the Texas coast were collected from mid-June 2010 through February 2011.


Through this 6-month period, no birds have shown signs of definite mortality, though some transmitters seem to have failed. At this point in the study, 4 birds traveled to Tamaulipas, Mexico, while 1 bird reached Louisiana. All birds that have dispersed from Texas thus far have been dark-morph birds. Site fidelity has been low, indicating similarities to closely related Egretta species that have been considered highly nomadic. This presentation will also feature observations extending through July. The satellite transmitters attached to the birds have a potential lifespan of 3 years, providing the opportunity for further data collection through the summer of 2013.

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Banner photo by Flickr user greg westfall.