Show simple item record

dc.contributor.advisorGreen, Clay
dc.contributor.authorHolderby, Zachary P. ( )
dc.identifier.citationHolderby, Z. P. (2009). Differences in reproductive ecology and behavior of the polymorphic reddish egret (Egretta rufescens) (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.
dc.description.abstractAssessing and maintaining genetic diversity is a concern for the conservation and management of a species, since variations within a species dictate its evolutionary potential. The Reddish Egret Egretta rufescens is a relatively rare heron species that exhibits white-dark plumage polymorphism. Different regions within the Reddish Egret's geographic range have different ratios of dark and white morphs. This may imply different microevolutionary processes affecting the frequency of the two morphs in different habitats and populations. I investigated how this phenotypic difference influences the behavior and reproductive ecology of the white and dark morph Reddish Egrets in the upper Laguna Madre of Texas. On dredge spoil islands in the Laguna Madre, Reddish Egret nesting pairs were observed during forty minute focals as they courted, built nests, and raised young. I collected time-spent behavioral data, reproductive ecology information, and characterized vegetation of nests and the surrounding area. Regurgitant from chicks was collected opportunistically to determine differences in diversity and abundance of prey fed to young. Nest vigilance and nest initiation did not differ between morphs or nest sites, but nest attendance varied between morphs depending on nest site. Feeding time of chicks differed between morphs and is potentially related to foraging efficiency and time of day. Nest cover did not vary between morphs within sites, but varied significantly between sites and between random points and nests within sites. This indicates strong selection of nest sites within colonies. The information obtained provides valuable insights into the ecological diversity of polymorphic species, and information on nest site selection and prey diversity that could be considered for the conservation of this rare waterbird.
dc.format.extent65 pages
dc.format.medium1 file (.pdf)
dc.titleDifferences in Reproductive Ecology and Behavior of the Polymorphic Reddish Egret (Egretta rufescens)
dc.contributor.committeeMemberWeckerly, Butch
dc.contributor.committeeMemberAspbury, Andrea State University--San Marcos of Science


This item is restricted to the Texas State University community. TXST affiliated users can access the item with their NetID and password authentication. Non-affiliated individuals should request a copy through their local library’s interlibrary loan service.

If this is your thesis or dissertation, you can make it open access. This will allow all visitors to view the document. To request open access, fill out the form linked below:

This item appears in the following Collection(s)

Show simple item record