The Inner Bir d GARY W. KAISER T h e I n n e r B i r d Anatomy and Evolution UBCPress . Vancouver . Toronto © UBC Press 2007 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without prior written permission of the publisher, or, in Canada, in the case of photocopying or other reprographic copying, a licence from Access Copyright (Canadian Copyright Licensing Agency), www.accesscopyright.ca. 15 14 13 12 11 10 09 08 07 5 4 3 2 1 Printed in Canada on ancient-forest free paper (100% postconsumer recycled) that is processed chlorine- and acid-free, with vegetable-based inks. Library and Archives Canada Cataloguing in Publication Kaiser, Gary W. The inner bird: anatomy and evolution / Gary W. Kaiser. Includes bibliographical references and index. ISBN 978-0-7748-1343-3 1. Birds – Anatomy. 2. Birds – Evolution. I. Title. QL697.K24 2007 571.3’18 C2007-900240-4 Canada UBC Press gratefully acknowledges the financial support for our publishing program of the Government of Canada through the Book Publishing Industry Development Program (BPIDP), and of the Canada Council for the Arts, and the British Columbia Arts Council. Printed and bound in Canada by Friesens Set in Arrus and Aurora by Artegraphica Design Co. Ltd. Text designer: Irma Rodriguez Project editor: Francis Chow UBC Press The University of British Columbia 2029 West Mall Vancouver, BC V6T 1Z2 604-822-5959 / Fax: 604-822-6083 www.ubcpress.ca For Dr. Alice Wilson, Dr. Donald C. Maddox, Mr. Herb Groh, and all the other adult mentors of the Macoun Field Club, the Ottawa Field-Naturalists’ program for young people This page intentionally left blank Contents Figures and Tables / ix Acknowledgments / xiii Introduction / 1 Part 1: What Is a Bird? 1 The Bird beneath the Feathers / 15 How adaptations for flight allow a bird to earn a living on the ground 2 A Bird Is an Animal with Hollow Bones / 40 Special features of avian bones and their assembly as a skeleton 3 A Bird Is Like a Dinosaur / 86 Features shared by birds and their reptilian ancestors 4 A Bird Is Not So Like a Dinosaur / 108 Features that distinguish birds from their reptilian ancestors Part 2: What Kind of Bird Is It? 5 The Kinds of Birds / 133 Classification and taxonomy 6 That Bird Is Different from the Other One / 169 Evolutionary relationships among families of birds Part 3: How Does a Bird Fly? 7 Feathers and Feathered Dinosaurs / 205 Flight in early birds and birdlike animals 8 Birds with a Modern Shape / 235 Birds cease to look like feathered dinosaurs and become skilled fliers 9 Birds on Land / 275 A robust design helps birds compete with mammals 10 Birds at Sea / 305 Sophisticated aerodynamics take birds onto oceans Conclusion / 344 Appendices 1 Birds in Relation to Other Vertebrate Animals / 346 2 Geological Time Scale / 347 Glossary of Ornithological Terms / 349 Literature Cited / 360 Index / 372 Figures and Tables Figures 1.1 Major elements in the avian skeleton / 18 1.2 Dorsal view of the skull of a Pacific Loon / 19 1.3 The flattened disc of the avian eye in cross-section / 22 1.4 The specialized eyes of an owl / 23 1.5 The hyoid apparatus of the Chattering Lory, a parrot / 26 1.6 Relationship of the brain and eye in the skull of a Yellow-billed Hornbill / 28 1.7 Caudal or posterior views of the skulls in four birds, showing the positions of the foramen magnum and occipital condyle / 29 1.8 Two extremes in the shapes of the tarsometatarsus / 32 1.9 The basic arrangements of toes in birds / 34 1.10 Variations in the proportions of the major skeletal elements in the wings of three aerial specialists among small forest birds / 36 2.1 Sagittal section through the upper humerus of a Common Murre / 49 2.2 Sagittal section through the skull of a Helmeted Hornbill / 49 2.3 Movement of the upper jaw in parrots / 58 2.4 Neck vertebrae supported by a sling of neck ligaments in a chicken / 61 2.5 Two different methods of lowering the head in extremely long-necked birds / 62 2.6 The first two cervical vertebrae in a Brandt’s Cormorant / 63 2.7 Thoracic vertebra from a Common Loon / 68 2.8 Skeleton of the thoracic and sacral regions in the Hoatzin and Common Murre / 70 2.9 Lateral and ventral views of vertebrae in the Cassin’s Auklet near the meeting of the thoracic and sacral regions / 72 2.10 The lumbar interface in a Double-crested Cormorant / 73 2.11 The lumbar interface in a Turkey Vulture and a Great Horned Owl / 74 2.12 Cross-section through the hipbones of a Bald Eagle / 75 2.13 The hypotarsus in a Common Raven / 84