Bat Echolocation Research A handbook for planning and conducting acoustic studies Second Edition Erin E. Fraser, Alexander Silvis, R. Mark Brigham, and Zenon J. Czenze EDITORS Bat Echolocation Research A handbook for planning and conducting acoustic studies Second Edition Editors Erin E. Fraser, Alexander Silvis, R. Mark Brigham, and Zenon J. Czenze Citation Fraser et al., eds. 2020. Bat Echolocation Research: A handbook for planning and conducting acoustic studies. Second Edition. Bat Conservation International. Austin, Texas, USA. Tucson, Arizona 2020 This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License ii Table of Contents Table of Figures ....................................................................................................................................................................... vi Table of Tables ........................................................................................................................................................................ vii Contributing Authors .......................................................................................................................................................... viii Dedication…… .......................................................................................................................................................................... xi Foreword…….. ........................................................................................................................................................................... 1 Editors’ Foreword ................................................................................................................................................................... 2 Overview ................................................................................................................................................................................ 2 Handbook Objectives and Scope .................................................................................................................................. 2 Contents .................................................................................................................................................................................. 3 Glossary………. ........................................................................................................................................................................... 5 Chapter 1. Introduction to Bat Echolocation ......................................................................................................... 9 Introduction .......................................................................................................................................................................... 9 Evolution of echolocation in bats ................................................................................................................................. 9 What are “acoustic data”?.............................................................................................................................................. 11 What can we learn using acoustic techniques? .................................................................................................... 12 How do we visualize acoustic data? .......................................................................................................................... 13 Is acoustic monitoring the right approach for your projects? ....................................................................... 14 Conclusion ........................................................................................................................................................................... 16 Chapter 2. Acoustic Survey Design .......................................................................................................................... 16 Introduction ........................................................................................................................................................................ 16 Common study types and survey foci ...................................................................................................................... 17 Stages of knowledge ................................................................................................................................................... 17 Species diversity ........................................................................................................................................................... 19 Presence/absence ........................................................................................................................................................ 19 Activity patterns ........................................................................................................................................................... 20 Behavior ........................................................................................................................................................................... 22 Population monitoring .............................................................................................................................................. 25 Sampling approaches ...................................................................................................................................................... 28 Active acoustics ............................................................................................................................................................ 29 Passive acoustics .......................................................................................................................................................... 29 Summary .............................................................................................................................................................................. 31 Chapter 3. Bat Detector Choice and Deployment .............................................................................................. 33 Introduction ........................................................................................................................................................................ 33 iii Bat detector types............................................................................................................................................................. 34 Trade-offs in detector hardware ................................................................................................................................ 34 Effective bat detector deployment ............................................................................................................................ 37 Summary .............................................................................................................................................................................. 41 Chapter 4. Echolocation Call Identification .......................................................................................................... 43 Introduction ........................................................................................................................................................................ 43 Call identification process — overview ................................................................................................................... 44 Detecting bat calls ........................................................................................................................................................ 46 Parameterizing bat calls ............................................................................................................................................ 48 Identifying bat calls ..................................................................................................................................................... 49 Manual identification of bat calls ............................................................................................................................... 54 Automated identification of bat calls ........................................................................................................................ 56 Intra-specific variation in echolocation calls ........................................................................................................ 58 Call Libraries ....................................................................................................................................................................... 60 Call libraries as a reference for manual ID ........................................................................................................ 62 Call libraries for machine learning and automated classifiers .................................................................. 62 A suggestion for managers: Develop call analysis guidelines that are specific to the various regions in your area ......................................................................................................................................................... 64 Summary .............................................................................................................................................................................. 64 Chapter 5. Data, Analysis, and Inference