Level: N DRA: 34 Science Strategy: Visualize Word Count: 606 3.5.22 Build Vocabulary HOUGHTON MIFFLIN Online Leveled Books ISBN-13: 978-0-547-02177-5 ISBN-10: 0-547-02177-1 1032074 H O UG H T O N M IF F L IN by Cally Green PHOTOGRAPHY CREDITS: Cover Arthur Morris/Birds As Art. 1 Arthur Morris/Birds As Art. 2–3 © James L. Amos/CORBIS. 5 Lew Robertson/jupiterimages. 6 Arthur Morris/Birds As Art. 7 Arthur Morris/Birds As Art. 8 BATES LITTLEHALES/National Geographic Image Collection. 9 © Wolfgang Kaehler/CORBIS. 10 © Spencer Grant/Photo Edit. Copyright © by Houghton Mifflin Company. All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying or recording, or by any information storage or retrieval system without the prior written permission of the copyright owner unless such copying is expressly permitted by federal copyright law. With the exception of nonprofit transcription into Braille, Houghton Mifflin is not authorized to grant permission for further uses of this work. Permission must be obtained from the individual copyright owner as identified herein. Address requests for permission to make copies of Houghton Mifflin material to School Permissions, Houghton Mifflin Company, 222 Berkeley Street, Boston, MA 02116. Printed in China ISBN-13: 978-0-547-02177-5 ISBN-10: 0-547-02177-1 1 2 3 4 5 6 7 8 9 RRD 15 14 13 12 11 10 09 08 Hundreds of swallows migrate each year. It happens every spring. Thousands of small, graceful birds fill the sky, moving through the air with a purpose. They have all flown a long distance toward a place they know. They have important work to do. 2 After a summer spent in the sheltered walls of an old church, they will leave to start another long trip. They will fly back to where they started in the spring. What are these small birds? Where are they going? These are swallows, on their way to or from their California home. 3 Capistrano The l