British Bat Calls: A Guide to Species Identification

By Jon Russ and Bat Conservation Trust

Knowledge of bat echolocation and social calls, and identification using ultrasonic ‘bat detectors’ and sound analysis software, has grown significantly in the last decade. In this practical guide Jon Russ and contributors (Kate Barlow, Philip Briggs & Sandie Sowler) present the latest information in a clear and concise manner.

The book covers topics including the properties of sound, how bats use sound, bat detectors and recording devices, analysis software, and call analysis. For each species found in the British Isles, information is given on distribution, emergence times, flight and foraging behaviour, habitat, echolocation calls including parameters for common measurements, and social calls. Calls are described in the context of the different technologies employed to record them (heterodyne, frequency division and time expansion). Various sonograms for each species are displayed in BatSound and AnaLookW. A species echolocation guide is included.

• Language: English
• Publisher: Pelagic Publishing
• Release date: Jul 2, 2012
• ISBN: 9781907807268

Jon Russ

Jon Russ first became interested in bats while completing undergraduate research into pipistrelle social calls as part of a degree in Zoology at the University of Aberdeen. This led to a PhD at Queen’s University Belfast investigating Northern Ireland’s bats. Jon has been involved in a wide variety of bat-related projects in both temperate and tropical areas. Jon is Director of Ridgeway Ecology Ltd, a specialist bat consultancy. After more than 25 years of involvement in bat research and conservation, he continues to be fascinated by these remarkable mammals.

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Pelagic Publishing | www.pelagicpublishing.com

Published by Pelagic Publishing

www.pelagicpublishing.com

PO Box 725, Exeter, EX1 9QU, United Kingdom

British Bat Calls

A guide to species identification

ISBN 978-1-907807-25-1 (Pbk)

ISBN 978-1-907807-26-8 (eBook)

Copyright © 2012 Jon Russ

All rights reserved. No part of this document may be produced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without prior permission from the publisher.

While every effort has been made in the preparation of this book to ensure the accuracy of the information presented, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Pelagic Publishing, its agents and distributors will be held liable for any damage or loss caused or alleged to be caused directly or indirectly by this book.

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library.

Cover image © NHPA/Melvin Grey

Greater horseshoe bat, Rhinolophus ferrumequinum in flight

Typeset and eBook by Graphicraft Limited, Hong Kong

Contents

Acknowledgements

Preface

1.  Introduction

2.  Bats and sound

2.1 Properties of sound

2.2 Signal acquisition

2.3 Representing and describing sound

2.4 How bats use sound

3.  Equipment

3.1 Bat detectors

3.2 Recording sound

4.  Call analysis

4.1 Sound analysis software

4.2 Automatic recognition software

4.3 Using sound analysis software

4.4 Measuring call parameters

4.5 AnalookW

4.6 Common analysis problems

5.  Species echolocation guide

6.  Species identification

Bibliography

Index

About the author

Jon Russ first became interested in bats in 1994 while completing undergraduate research into pipistrelle social calls as part of an honours degree in zoology at the University of Aberdeen. This led to a PhD at Queen’s University Belfast investigating the community composition, habitat associations and echolocation calls of Northern Ireland’s bats. Since then he has been involved in a wide variety of bat-related projects which have taken him from the freezing mists of north-east Scotland and the fine soft nights of Ireland to the humid rainforests of Madagascar, Thailand and Burma. Jon is the Director of Ridgeway Ecology, a specialist bat consultancy, and has worked for a number of years for the Bat Conservation Trust coordinating the iBats project in the UK and Eastern Europe. After nearly 20 years involvement in bat research and conservation he continues to be fascinated by these remarkable mammals.

About the contributors

Kate Barlow works for the Bat Conservation Trust (BCT) as the Development Manager for the National Bat Monitoring Programme. She has a long-term interest in bats, sparked by catching exotic species during summer expeditions to South America as an undergraduate. Kate has held a bat licence in the UK since 1993, worked as a professional bat consultant before joining BCT and obtained a PhD in bat ecology in 1997 through her research on ecological differences between what are now two separate species of pipistrelle.

Philip Briggs works for the Bat Conservation Trust as the Projects Manager for the National Bat Monitoring Programme. He has a lifelong interest in wildlife, has been involved in bat conservation since 2001 and holds a bat licence. Philip has a particular interest in bat echolocation and delivers training in species identification using bat detectors and sound analysis.

Dr Sandie Sowler is a bat specialist and ecological consultancy trainer, specialising in delivering training in bat-related subjects to the profession, including the use of bat detectors, particularly Anabat and Analook. She has been involved with bats and in bat research since 1969, has a PhD in bat ecology, has had a UK bat licence since 1985 and has worked as a professional ecological consultant, specialising in bats and developments since 1995. Sandie currently delivers Anabat training courses in several European countries and also in Southern Africa.

This book was completed in collaboration with the Bat Conservation Trust (BCT) and some sections draw on existing BCT training material. The Bat Conservation Trust was formed in 1991 and is the only UK-wide organisation solely devoted to the conservation of bats and their habitats. BCT’s vision is a world where bats and people thrive together in harmony and is working towards a future where our bat populations are viable and actively supported and enjoyed by people across the UK. BCT is a registered charity with nearly 5,000 members and a team of over 30 staff including scientists, biodiversity officers, database managers and specialists in training, outreach and education, volunteer engage-ment, fund raising, media and membership. It has particular expertise in bat monitoring and delivery of projects to conserve bats. Through the hard work and dedication of our volunteer network, BCT runs the National Bat Monitoring Programme, which comprises a number of national annual surveys to monitor the status of many of our bat species across a range of habitats. As part of this programme we provide training and information for volunteers on different types of bat detectors and recording devices (on which some of the information in this book is based), and helpful information about bat echolocation. Visit www.bats.org.uk to find out more.

Acknowledgements

I am hugely indebted to Nigel Massen of Pelagic Publishing who resurrected this project and to Kate Barlow, Philip Briggs and Sandie Sowler who contributed greatly to the content. Specifically, Kate and Philip wrote the majority of Chapters 3 and 4 (Equipment and Call Analysis), refined Chapters 2 and 6 (Bats and Sound; Species Identification) and commented on the final draft, while Sandie added the frequency division sections to Chapter 6 (Species Identification). Sandie also provided the text on which the zero crossing information in Chapter 4 is based. Without their input this book would not have been completed. Parts of Chapters 3 and 4 draw on BCT resources written by Jules Agate and Colin Catto.

Many thanks to Danilo Russo and Jules Agate for commenting on earlier versions of the book and to Hazel Gregory and Steve Russ for providing much needed proofreading. Steve additionally helped refine the Introduction and Preface.

I am grateful to Tom McOwat for producing the beautiful illustrations of bat wing shapes, ear shapes and habitats in Table 2.1 and the pipistrelle bat in flight on the title page.

John Altringham generously supplied the time-expanded recording of a feeding buzz of Myotis alcathoe and a copy of two research articles (Jan et al., 2010 and von Helversen et al., 2001) upon which much of the Myotis alcathoe section is based. David Lee and Denise Foster provided a time-expanded recording of the echolocation call of a hand-released Myotis alcathoe and Alex Lefevre provided a recording of M. alcathoe from Hermeton-sur-Meuse in the south of Belgium. David also kindly provided a recording of a social call of Nyctalus noctula. Jules Agate provided a time-expanded recording of the echolocation calls of Myotis bechsteini. Erika Dahlberg provided the time-expanded recordings of a Plecotus auritus social call, the echolocation and social calls of Plecotus austriacus, as well as a copy of her BSc Hons thesis (Dahlberg, 2004) containing measured parameters of the calls of these two species. Arjan Boonman supplied time-expanded social calls of Myotis nattereri and Myotis daubentonii swarming in a cave. Mathieu Lundy provided a time-expanded M. nattereri echolocation and social call and Austin Hopkirk generously provided a time-expanded recording of M. daubentonii leaving a roost. A number of people generously allowed us to use their Anabat recordings: David Hunter provided lesser horseshoe bat social calls; David Woolley allowed use of his greater horseshoe bat social calls, whiskered bat distress calls and Leisler’s bat echolocation calls; Stephen Davison provided recordings of the social calls of whiskered bats emerging from a roost; Claire Snowball provided noctule social calls; David Fee provided brown long-eared bat echolocation and social calls; Orly Razgour provided grey long-eared bat echolocation and social calls; and Margaret Clarke kindly provided a barbastelle social call.

The following people also assisted during the protracted process of creating this book: Arjan Boonman, Darren Bradley, Colin Catto, Thierry Disca, Andrew Heath, Marc Holderied, Austin Hopkirk, Gareth Jones, Kate Jones, Herman Limpens, Iain Mackie, Kate McAney, Andrew McLeish, Katie Parsons, Lars Pettersson, Dave Russ, Mark Smyth, Jackie Underhill and Nancy Vaughan.

I would particularly like to thank Paul Racey who not only inspired my interest in bats but also enabled me to pursue a career that has been so rewarding.

The software programs Batsound v3.31 (Pettersson Elektronik AB, Uppsala, Sweden), Avisoft SASLab v4.6 and AnalookW v3.3f (Chris Corben) were used to construct the sonograms, oscillograms and power spectra displayed in this book. The majority of the calls were recorded using a Pettersson D-980 bat detector (Pettersson Elektronik AB, Uppsala, Sweden).

The author welcomes comments regarding this book and would be grateful for any recordings of bat vocalisations that could be used in future editions (email: [e-mail]).

I would like to thank Eimear for all her love and support during the writing of this book, which is dedicated to Ellen, our beautiful daughter.

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Preface

While working on a PhD in the late 1990s, investigating the community composition, habitat associations and ultrasound of Northern Ireland’s bats, I compiled a series of species notes to assist me with identification of bats by their echolocation calls heard or recorded in the field. I soon realised that this could be of use to other bat enthusiasts. Combining these notes with handouts for bat detector workshops, it gradually metamorphosed into a beginners guide to bat identification using heterodyne and time expansion detectors. Those species also occurring in Britain were added in response to demand and sections on how bats use sound and the recording and analysis of sound were included in order to support the identification guide. In 1999 The Bats of Britain and Ireland: Echolocation Calls, Sound Analysis, and Species Identification was published by Alana Books.

Over the following years I gradually accumulated new recordings of echolocation calls and social calls of British bats, not only those I had recorded myself but also those that had been kindly sent to me by other bat enthusiasts. It seemed like a good idea to make these available to others through the publication of a follow-up to that initial guide. The rapid increase in the number of people with an interest in bats, ranging from voluntary bat group workers and researchers to the growing number of bat consultants, persuaded me that such an update would be useful to many in the field of bat conservation. With the invaluable input of Kate Barlow and Philip Briggs of the Bat Conservation Trust and Sandie Sowler, an expert on identification of bat calls using the Anabat system, the scope of the book grew to include updated sections on bats and sound, a much improved and comprehensive section on species identification, and new chapters on equipment and call analysis. I hope it will be useful to amateurs and professionals alike.

1   Introduction

In 1793, Lazzaro Spallanzani, an Italian Catholic priest, biologist and physiologist, demonstrated that bats were able to avoid obstacles without the aid of vision. He stretched thin wires with small bells attached across a completely darkened room and observed that bats were able to fully navigate between them without causing the bells to ring. Blinding the bats also did not impair their ability to manoeuvre around them. Meanwhile, a Swiss zoologist, Charles Jurine, revealed that blocking one of the ears of a bat spoiled its navigating abilities, a finding that Spallanzani then pursued. A series of experiments which involved blocking the ears or gluing the muzzle closed led him to conclude that while bats did not have much use for their eyes, any interference with their ears that adversely affected hearing was disastrous, resulting in them colliding with objects they could usually avoid and being unable to forage for prey. He concluded that ‘The ear of the bat serves more efficiently [than the eye] for seeing, or at least for measuring distance’. At the time, Spallanzani’s findings were met by his fellow scientists with ridicule and scepticism as bats were believed incapable of producing any sound and therefore such results defied logic.

Nearly 150 years after Spallanzani’s work, Donald R. Griffin, while an undergraduate at Harvard University in the 1930s, took an interest in Spallanzani’s ‘bat problem’. New advances