Semester of Graduation

Summer 2019

Degree

Master of Science (MS)

Department

School of Renewable Natural Resources

Document Type

Thesis

Abstract

As the coastline of Louisiana shifts with global climate change, subsidence, and accelerated sea level rise, important breeding islands for colonial nesting waterbirds are disappearing. In many recent studies flooding has been a leading cause of nest failure for a variety of species, especially those that nest on the ground. I examined the nest success of four species of colonial nesting waterbirds with various nesting strategies on Rabbit Island in southwestern Louisiana during 2017 and2018 by determining nest and fledging success. I monitored 855 nests, including 457 Brown Pelicans nests with an estimated hatch probability of 70%, 270 Forster’s Terns with an estimated 12% hatch likelihood, 92 Tricolored Herons at a hatch success rate of 77%, and 36 Roseate Spoonbills with the highest hatch rate at 70%. My findings indicate that nest strategy and nest timing have a significant impact on survival rate, however the effect is mediated by conditions within a specific breeding season. The largest cause of nest failure was flooding for all species except Tricolored Herons, indicating that the island may currently be too low for small differences in elevation between nest sites to impact survival. Increasing island elevation could reduce the probability of nest failure due to overwash, but increased elevation may also lead to island abandonment or reduced nest success due to increased chance of island colonization by rank woody vegetation, mammalian predators, and/or fire ants.

Committee Chair

King, Sammy

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