Bat echolocation research: a handbook for planning and conducting acoustic studies

Fraser, Erin; Silvis, Alexander; Brigham, R. Mark; Czenze, Zenon

The Handbook summarizes all the key steps in conducting an acoustic survey of a bat community, including project planning, strategies for data collection, approaches to analysis and interpretation, a guide to purchasing a bat detector, and a series of case studies. Chapter 1 (“Introduction to bat echolocation”) provides a broad introduction to the theme, including a discussion of why and how bats echolocate, and a brief description of acoustic data, as well as what can be discerned about a bat community using acoustic techniques. Chapter 2 (“Acoustic survey design”) focuses on acoustic survey design, stressing the importance of identifying a clear research question and approach, and summarizing some of the most common questions that researchers investigate using acoustic techniques. Chapter 3 (“Bat detector choice and deployment”) discusses the difficult task of choosing the appropriate detector and summarizing the different technological approaches, as well as the trade-offs involved with selecting one style of detector over another. Chapter 4 (”Echolocation call identification”) focuses on strategies for identifying recordings of echolocation calls, starting with a discussion of the challenges associated with this task, an overview of both manual and automated approaches, and a section on using and creating call libraries, which is crucial for researchers working in areas where bat communities have received little or no study. Chapter 5 “Data, analysis, and inference”) deals with data management, analysis, and inference. It includes a discussion about strategies for data management that contains a section on the nature and use of databases. Furthermore, it describes different approaches to statistical analyses, many of which are intuitively linked to the suggestions for study design in Chapter 2. Chapters 2 through 5 each conclude with a “Some additional suggestions” section, which were sent to us when we asked a group of bat acoustic experts what they considered to be some common pitfalls associated with the technique. The final chapter of the Handbook (“Case studies”) includes five case studies, each of which summarizes a previously published study or studies that used acoustic survey techniques. The goal of this section is to demonstrate how many of the principles discussed throughout the Handbook have been applied in real-life scenarios. We selected the case studies to provide examples from a range of geographic locations, using various detecting technologies, and asking diverse questions about bat communities. Throughout the Handbook, when photos or recordings of individual species are provided and labeled, we have identified the species of interest by scientific name and by the common name provided by the online resource, Bats of the World: A Taxonomic and Geographic Database (Simmons and Cirranello 2020), unless stated otherwise. On behalf of all contributors to the Handbook, we hope that this guide will help demystify the process of eavesdropping on bats and promote high standards in future acoustic studies of bat activity. Erin Fraser, Alex Silvis, Mark Brigham, and Zenon Czenze