April Pulley Sayre - Secrets of Sound: Studying the Calls of Whales, Elephants, and Birds

Houghton Mifflin Company Boston

Secrets of Sound

For my mother, Elizabeth Richardson Pulley, a great listener
A.P.S.

Acknowledgments

I am deeply grateful to the following people who made this book possible by giving generously of their time and expertise: Katy Payne, Mya Thompson, and Melissa Groo at the Elephant Listening Project of the Cornell Lab of Ornithology's Bioacoustics Research Program; Bill Evans of Old Bird; Dr. Jan Randall of San Francisco State University; Dr. Ron Hoy of the Cornell University Department of Neurology and Behavior; Dr. Sandra Gaunt of the Ohio State University Borror Laboratory of Bioacoustics; Dr. Bill Barklow of Framingham State College; Dr. Christopher Clark of the Cornell Laboratory of Ornithology's Bioacoustics Research Program; and wildlife photographer Lynda Richardson.

Photo on by April Pulley Sayre. Scientists listen in on underwater concerts sung by humpback whales.
Photo on by Joyce Poole. Katy Payne studies the sounds and behaviors of elephants.
Photo on by Jeff Sayre. Albatrosses open their bills and then snap them closed during a courtship display.

Copyright 2002 by April Pulley Sayre

All rights reserved. For information about permission to reproduce selections from this book, write to
Permissions, Houghton Mifflin Company, 215 Park Avenue South, New York, New York 10003.

www.houghtonmifflinbooks.com

Book design by Lisa Diercks
The text of this book is set in Minion.

Library of Congress Cataloging-in-Publication Data
Sayre, April Pulley.
Secrets of sound : studying the calls and songs of whales, elephants, and birds / by April Pulley Sayre.
p. cm.
Includes bibliographical references (p.).
Summary: Examines the work of several bioacousticians, scientists who study the sounds made
by living creatures, discussing the results and importance of their research.
HC ISBN 0-618-01514-0 PA ISBN 0-618-58546-X
1. BioacousticsJuvenile literature. [1. Animal sounds.] I. Title.
QH510.5 .S28 2002 599.159dc21 2001051877

HC ISBN-13: 978-0618-01514-6
PA ISBN-13: 978-0618-58546-5

Printed in Singapore
TWP 10 9 8 7 6 5 4

Introduction

Wondering About Whales: Christopher Clark

Something in the Elephants' Silence: Katy Payne

Sounds in the Night Sky: Bill Evans

New Technologies, New Voices: The Future of Bioacoustics

Suggestions for Further Reading and Listening

How You Can Get Involved in Research and Conservation

Glossary

Index

Hippos can talk to one another above and below water. PHOTO BY LYNDA RICHARDSON

Squeaks. Wails. Whistles. Snorts. Songs. Drumming. All over the globe, animals are making sounds, and these days, more than ever, scientists are listening to them. In a desert in Uzbekistan, Dr. Jan Randall records sounds that wild gerbils make when they thump their feet on the ground. At a waterhole in Africa, Dr. Bill Barklow listens to the recently discovered underwater sounds of hippos. In Texas, Bill Evans rigs up microphones to record and identify the mysterious calls of night-migrating birds.

Meanwhile, on a ship off the coast of Hawaii, Christopher Clark lowers a special microphone into the ocean to listen to whales singing. He also analyzes secret recordings from hundreds of ocean microphones that the navy uses to track enemy submarines. The microphones record not just submarine noises but also, by accident, the songs of whales.

Scientists who study animal sounds are called bioacousticians, or acoustic biologists. Bioacoustics is the study of sounds made by living things. (Acoustics is the study of sound.) Bioacousticians study sounds made by mammals, insects, birds, frogs, and other creatures.

In recent years, hidden soundsbeyond the normal range of human hearinghave provided a whole new field of exploration. Katy Payne has discovered that elephants make soundslow, loud, and deepthat travel for many miles. Some of these sounds are too low for humans to hear, but people can feel them as a throbbing in the air.

Bioacousticians come from a wide range of backgrounds. Some start from a love of science,

Bill Barklow, a bioacoustic pioneer, listens to the underwater sounds of hippos. PHOTO BY LYNDA RICHARDSON

Scientists use a large microphone to focus in on the sound of the birds they are trying to record. PHOTO BY TIM GALLAGHER

others from a love of music or engineering. Over the years, many of these bioacousticians have worked together. Often what one bioacoustician discovers helps someone else. Their discoveries have built on one another, like notes in a symphony. Together, they are seeking a better understanding of the sounds animals make, what those sounds mean, and how to use this knowledge to help save endangered animals.

Christopher Clark and a colleague get a close-up look at a right whale off the coast of Argentina. PHOTO BY JANE MOON CLARK

Christopher Clark grew up in a house full of music. When he was nine, he attended a special boarding school for choir singers at St. John the Divine in New York City. He was definitely "tuned in" to sound from an early agebut back then, he wasn't listening to whales.

Today, Dr. Clark uses underwater microphones, called hydrophones, to hear the songs of whales. He is researching how whales use sound to navigate, communicate, and survive in the ocean. Clark is director of the Bioacoustics Research Program at the Cornell Lab of Ornithology in Ithaca, New York. There he works in laboratories, with computers, to analyze the whale songs he records. He also coordinates the work of other scientists who study birds, elephants, and other animals.

Clark loves his work. "I have to admit, I have a great job," he says. "I wouldn't trade it for the world." His favorite part of the job is studying whales in the wild.

To record whale sounds, Clark lowers a hydrophone about thirty-five feet down into the ocean. Using a headset attached to the hydrophone, he can hear whales clearly. But even without hydrophones, the whale sounds can sometimes be heard by people sitting in the boats above. A boat's hull can vibrate and make strange noises as a whale sings. Centuries ago, sailors thought these sounds were made by mermaids.

Top: As a student, in 1974, Christopher Clark (in the hat) helped Roger Payne carry microphones to the whale recording site in Argentina.