Ecological Drivers of Brown Pelican Movement Patterns and Reproductive Success in the Gulf of Mexico Juliet Sarah Lamb Clemson University, [email protected]
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Clemson University TigerPrints All Dissertations Dissertations 5-2016 Ecological Drivers of Brown Pelican Movement Patterns and Reproductive Success in the Gulf of Mexico Juliet Sarah Lamb Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Recommended Citation Lamb, Juliet Sarah, "Ecological Drivers of Brown Pelican Movement Patterns and Reproductive Success in the Gulf of Mexico" (2016). All Dissertations. 1645. https://tigerprints.clemson.edu/all_dissertations/1645 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. ECOLOGICAL DRIVERS OF BROWN PELICAN MOVEMENT PATTERNS AND REPRODUCTIVE SUCCESS IN THE GULF OF MEXICO A Dissertation Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Wildlife and Fisheries Biology by Juliet Sarah Lamb May 2016 Accepted by: Patrick Jodice, Committee Chair Robert Baldwin Yoichiro Kanno Robert Suryan ABSTRACT The effects of environmental change on vast, inaccessible marine ecosystems are often difficult to measure and detect. As accessible and highly visible apex predators in marine environments, seabirds are often selected as indicators for studying the effects of disturbance at lower trophic levels, although data are restricted both temporally and spatially. For example, studies of seabirds have historically been limited to the breeding season, with limited data being available throughout the remainder of the annual cycle. Additionally, understanding of habitat associations and behavior of seabirds in the marine environment comes primarily from pelagic seabirds, whose habitat year-round is generally in remote marine areas removed from anthropogenic development, while similar data from nearshore seabirds are less common. Such data gaps limit our understanding or life-history traits among seabirds, one of the most imperiled avian groups globally, and subsequently our ability to inform conservation and marine spatial planning. My goal was to examine ecological relationships of diet, breeding biology, and movement patterns of a nearshore tropical seabird, the Eastern brown pelican, in the Gulf of Mexico, one of the most anthropogenically developed marine ecosystems worldwide. While my results supported previous findings that nutritional conditions are a key driver of seabird reproductive success and recruitment, they differ in suggesting that prey availability and delivery rates are more important to reproductive rates than energetic value of prey species. Since direct measurement of reproductive rates is time-consuming and difficult to collect, I also tested an integrated measure of nutritional stress during development, feather corticosterone, as a predictor of nestling survival and fledging rates. ii Corticosterone predicted 94% of inter-colony variation in fledging success and was also correlated with post-fledging survival, making it a powerful tool for measuring demographic patterns in this species. To measure adult movement patterns, I deployed bird-borne biologgers to collect highly accurate spatial data from pelicans throughout the annual cycle. I found that individual breeders quickly returned to normal behavior after capture and tagging. GPS tracking also indicated that pelicans were highly mobile, ranging over large areas during the breeding season and migrating up to 2,500 kilometers during non-breeding. Movement patterns were influenced by local conspecific competition during both breeding and migration, such that birds from larger colonies moved longer distances year-round compared to those from smaller colonies. I also found a high degree of spatial, temporal, and individual variation in exposure to surface pollutants across the population. I recorded a high degree of individual variation in movement, which interacted with pollutant exposure to create a complex and varying distribution of risk throughout the northern Gulf metapopulation of brown pelicans. Understanding the factors driving this variation will inform future monitoring, conservation, and mitigation efforts for this species. iii DEDICATION To Dr. Farish Jenkins iv ACKNOWLEDGMENTS The research included in this dissertation was funded primarily by the Bureau of Ocean Energy Management and U.S. Geological Survey. I am also grateful to the Clemson College of Agriculture, Forestry, and Life Sciences (Wade Stackhouse and Marion Bailey Fellowships) and Sigma Xi for additional funding. Chapters 2-6 of this manuscript represent stand-alone publications intended for submission to peer-reviewed journals, and several collaborators participated as co-authors on the manuscripts. Patrick Jodice co-authored all five data chapters, Yvan Satgé co- authored Chapters 2, 3, and 5, Kathleen O’Reilly co-authored Chapter 3, and Christine Fiorello co-authored Chapter 2. Their contributions included project design and management (PJ, YS) assisting with data collection (YS, CF), lab and field work (KO, YS), data management (YS), and manuscript preparation (PJ, YS). Additional collaborators are included them in the acknowledgements sections of individual chapters. Although they are mentioned elsewhere, I’d like to especially thank Elizabeth Ford and Stève Desaivre for their dedicated work in the field. Jeff Gleason and Dave Moran were instrumental in funding, conceiving, and managing this project at the institutional level. Carolyn Wakefield has been of enormous help administratively. I would also like to thank the many volunteers that helped with fieldwork, particularly Julie Sullivan, Jill Sekeley, Lisa Burns, Caroline Poli, Amanda Hackney, Tim Wilkinson, Beau Hardegree, Mark Dumesnil, Justin Davis, Kimberley Middlebrooks, Joe Reinman, Megan Lamb, and John Harms. Scott Walter and Tommy King were instrumental in developing capture and attachment techniques. I thank Scott Walter, The Nature v Conservancy, National Audubon Society, Florida Fish and Wildlife Conservation Commission, and St. Mark’s National Wildlife Refuge for facilitating colony site access. At Clemson, my committee—Dr. Rob Baldwin, Dr. Yoichiro Kanno, and Dr. Rob Suryan—were extremely generous with their time, insight, and encouragement. I thank my labmates, especially Caroline Poli and Liz Zinsser (Project Puffin South) for their friendship and support. Ludovic Besaury assisted greatly with genetic sexing analysis as well as other lab work. I appreciate the additional travel support provided by the Clemson Graduate Student Government. Prior to her passing in October of 2014, Dr. Kate McFadden also had an important influence on this work. The support of my family— John, Diana, Anneka, and Susanne—has been a constant anchor. Finally, this project belongs to two people as much as it does to me: To Dr. Patrick Jodice, my advisor and, nevertheless, my friend. From the time I first spoke to him by phone, from beside a damp stone wall on a tiny Scottish island, he impressed me with his ability to anticipate my concerns and respond directly and insightfully. Over these past few years, I have learned at least as much simply watching him from day to day as I have working with him. His confidence in me has given me the space and resources to grow as a scientist, and his ability to respond to difficult situations with patience, honesty, and an intuitive grasp of others’ perspectives is a model I won’t soon forget. I am very lucky to know him. And to Yvan Satgé, who took this chance with me and has been there, if not every step of the way, at least the 95% kernel density of the steps. Tout mon cœur t’appartient, maintenant comme toujours. vi TABLE OF CONTENTS Page TITLE PAGE .................................................................................................................... i ABSTRACT ..................................................................................................................... ii DEDICATION ................................................................................................................ iv ACKNOWLEDGMENTS ............................................................................................... v LIST OF TABLES ........................................................................................................... x LIST OF FIGURES ...................................................................................................... xiii CHAPTER I. INTRODUCTION ......................................................................................... 1 Summary of dissertation content ............................................................. 3 Literature Cited ........................................................................................ 6 II. SHORT-TERM BEHAVIORAL AND REPRODUCTIVE EFFECTS OF BIRD-BORNE DATA LOGGER ATTACHMENT ON BROWN PELICANS (PELECANUS OCCIDENTALIS) ........................................ 9 Abstract .................................................................................................... 9 Introduction ............................................................................................ 10 Methods.................................................................................................. 13 Results .................................................................................................... 17 Discussion