UC Santa Cruz UC Santa Cruz Electronic Theses and Dissertations Title Comparative behavior, diet, and post-breeding strategies of two sympatric North Pacific albatross species (Phoebastria sp.) Permalink https://escholarship.org/uc/item/00m031m8 Author Conners, Melinda Publication Date 2015 Supplemental Material https://escholarship.org/uc/item/00m031m8#supplemental Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA SANTA CRUZ COMPARATIVE BEHAVIOR, DIET, AND POST-BREEDING STRATEGIES OF TWO SYMPATRIC NORTH PACIFIC ALBATROSS SPECIES A dissertation submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in OCEAN SCIENCES by Melinda G. Conners December 2015 The Dissertation of Melinda Grace Conners is approved: ______________________________ Dr. Scott A. Shaffer, Chair ______________________________ Professor Raphael Kudela ______________________________ Dr. Elliott L. Hazen ______________________________ Professor Daniel P. Costa ______________________________ Tyrus Miller Vice Provost and Dean of Graduate Studies Copyright © by Melinda Grace Conners 2015 ii Table of Contents LIST OF TABLES ..................................................................................................... vi LIST OF FIGURES .................................................................................................. viii THESIS ABSTRACT ................................................................................................ xi ACKNOWLEDGEMENTS ........................................................................................ xiii DEDICATION ......................................................................................................... xvii Introduction & Synthesis .................................................................................... 1 THESIS SUMMARY ................................................................................................................ 4 SYNTHESIS OF ECOLOGICAL IMPLICATIONS ........................................................................ 6 REFERENCES ........................................................................................................................ 8 CHAPTER ONE: Shadowed by scale: subtle behavioral niche partitioning in two synpatric, tropical breeding albatross species ............................................ 11 ABSTRACT ....................................................................................................................... 12 1.1 BACKGROUND ......................................................................................................... 13 1.2 METHODS................................................................................................................... 17 1.2.1 Study species and study location ................................................................... 17 1.2.2 Tracking methods ............................................................................................. 18 1.2.3 Individual characteristics ................................................................................. 18 1.2.4 Track analysis ..................................................................................................... 20 1.2.5 Foraging behavior: ............................................................................................ 20 1.2.6 Environmental data: ......................................................................................... 23 1.2.7 Statistical analyses: ........................................................................................... 23 1.3 RESULTS .................................................................................................................... 26 1.3.1 Individual characteristics ................................................................................. 27 1.3.2 Species and diurnal differences in movement parameters ........................ 27 1.3.3 Species differences in general track characteristics .................................... 28 1.3.4 Behavioral states – diurnal and species differences .................................... 28 1.3.5 Relationship between lunar phase and behavioral state ........................... 29 1.3.6 Within species foraging patterns .................................................................... 29 iii 1.3.7 Foraging patterns of black-footed albatrosses ............................................. 29 1.3.8 Foraging patterns of Laysan albatrosses ....................................................... 31 1.3.9 Intrinsic factors and foraging patterns .......................................................... 31 1.3.10 Extrinsic factors (year, wind and lunar phase) and foraging patterns .... 32 1.4 DISCUSSION ............................................................................................................. 33 1.4.1 Beyond “Area-Restricted Search” foraging behavior .................................. 33 1.4.2 Nocturnal and diurnal niche partitioning ...................................................... 35 1.4.3 Within- and among- species niche partitioning ........................................... 37 1.5 CONCLUSION ........................................................................................................... 40 1.6 REFERENCES ........................................................................................................... 40 CHAPTER TWO: Identifying fisheries-associated diet in the stomach oil of tube-nosed seabirds using quantitative lipid analysis ....................................... 64 ABSTRACT ....................................................................................................................... 65 2.1 INTRODUCTION ........................................................................................................ 66 2.2 METHODS .................................................................................................................. 71 2.2.1 Study Species ..................................................................................................... 71 2.2.2 Stomach Oil ........................................................................................................ 72 2.2.3 Lipid Library of Potential Albatross Prey ....................................................... 73 2.2.4 Lipid analysis ...................................................................................................... 74 2.2.5 Understanding prey-driven error in the QFASA model ............................... 77 2.2.6 Statistical analyses ............................................................................................ 78 2.3 RESULTS .................................................................................................................... 79 2.3.1 Qualitative assessment of prey similarity by lipid signatures .................... 79 2.3.2 Species and functional group error associated with QFASA modeling ..... 80 2.3.3 Albatross Diet .................................................................................................... 81 2.3.4 Effect of Species, Breeding Phase, Sex and Age on Diet Composition ...... 81 2.3.5 Fisheries-associated diet.................................................................................. 82 2.3.6 Dietary specialization in albatrosses .............................................................. 83 2.4 DISCUSSION ............................................................................................................. 84 2.4.1 Incidence of fisheries-associated resources in albatross diet .................... 84 2.4.2 Deep, mesopelagic layer feeds surface-scavenging albatross ................... 86 2.4.3 Greater behavioral and dietary flexibility in black-footed albatrosses ..... 87 2.4.4 Older albatrosses consume more squid than younger birds ..................... 89 2.4.5 Estimating diet with QFASA: the good, the bad, and the ugly ................... 89 iv 2.5 REFERENCES ........................................................................................................... 91 CHAPTER THREE: Interactions of self-maintenance, sex, and age impact the post-breeding migrations of two long-lived seabird species ........................... 123 ABSTRACT ..................................................................................................................... 124 3.1 BACKGROUND ....................................................................................................... 125 3.2 METHODS ................................................................................................................ 130 3.2.1 Tracking methods ........................................................................................... 130 3.2.2 Breeding Sequences as a Proxy of Molt ...................................................... 131 3.2.3 Statistical analyses .......................................................................................... 132 3.2.4 Estimating locations from geolocation data ............................................... 133 3.2.5 General characterization of post-breeding migrations ............................. 134 3.2.6 Space Use ......................................................................................................... 134 3.2.7 The dynamics of space-use change relative to molt series ...................... 135 3.2.8 Habitat use as a function of species, sex, age, molt series ....................... 135 3.2.9