Helpers at birds nests_ a worldwide survey of cooperative breeding and related behavior

528 Pages·1999·4.39 MB·English

by  Alexander Frank Skutch, Dana Gardner

Helpers At Birds' Nests : A Worldwide Survey of
title:
Cooperative Breeding and Related Behavior
author: Skutch, Alexander Frank.
publisher: University of Iowa Press
isbn10 | asin: 0877456747
print isbn13: 9780877456742
ebook isbn13: 9781587292255
language: English
subject Birds--Behavior, Cooperative breeding in animals.
publication date: 1999
lcc: QL698.3.S55 1999eb
ddc: 598.1563
subject: Birds--Behavior, Cooperative breeding in animals.
Page iii
Helpers at Birds' Nests
A Worldwide Survey of Cooperative Breeding and Related Behavior
An Expanded Edition
Alexander F. Skutch
Illustrated by Dana Gardner
Foreword by Stephen T. Emlen
Page iv
University of Iowa Press, Iowa City 52242
Copyright © 1999 by the University of Iowa Press
All rights reserved
Printed in the United States of America
http://www.uiowa.edu/~uipress
No part of this book may be reproduced or used in any form or by any means, electronic
or mechanical, including photocopying and recording, without permission in writing
from the publisher. All reasonable steps have been taken to contact copyright holders of
material used in this book. The publisher would be pleased to make suitable arrangements
with any whom it has not been possible to reach.
Printed on acid-free paper
Library of Congress
Cataloging-in-Publication Data
Skutch, Alexander Frank, 1904-
Helpers at birds' nests: a worldwide survey of cooperative breeding and related
behavior/by Alexander F. Skutch; illustrated by Dana Gardner; foreword by Stephen T.
Emlen.An expanded ed.
p. cm.
Includes bibliographical references and index.
ISBN 0-87745-674-7 (pbk.)
1. BirdsBehavior. 2. Cooperative breeding in animals. I. Title.
QL698.3.S55 1999
598.1563dc21 98-51782
99 00 01 02 03 P 5 4 3 2 1
Page v
To Ian Rowley, pioneer in the quantitative study of cooperative breeding
Page vii
Contents
Foreword to the 1999 Edition by Stephen T. Emlen ix
Preface to the 1999 Edition xiii
1. Introduction 1
2. Oceanic Birds 7
3. Precocial Birds 12
4. Diurnal Raptors 17
5. Rails, Coots, and Gallinules 21
6. Pigeons and Doves 26
7. Parrots 28
8. Cuckoos and Anis 31
9. Hoatzins 39
10. Swifts 43
11. Wood-hoopoes 46
12. Todies 51
13. Kingfishers 54
14. Bee-eaters 63
15. Hornbills 68
16. Puffbirds 73
17. Barbets 76
18. Toucans 79
19. Woodpeckers 83
20. Ovenbirds 92
Page viii
21. American Flycatchers 96
22. Cotingas 100
23. New Zealand Wrens 103
24. Swallows 105
25. Crows and Jays 109
26. Mudnest Builders 130
27. Australian Butcher-birds and Bell-magpies 136
28. Titmice 138
29. Long-tailed Tits and Bushtits 142
30. Nuthatches 148
31. Treecreepers 151
32. Wrens 154
33. Gnatcatchers and Old World Warblers 160
34. Wren-warblers 163
35. Old World Flycatchers 170
36. Thrushes 173
37. Babblers and Allies 178
38. Mockingbirds, Thrashers, and Catbirds 186
39. Accentors 189
40. Wood-swallows 191
41. Shrikes 195
42. Helmet-Shrikes 199
43. Starlings 201
44. Honeyeaters 206
45. White-eyes 211
46. Wood-warblers 213
47. Tanagers and Honeycreepers 216
48. New World Blackbirds and Orioles 222
49. Grosbeaks, Finches, and Sparrows 227
50. Weavers and Sparrows 234
51. The Significance of Interspecific Helping 245
52. Characteristics of Cooperative Breeders 252
53. Benefits and Evolution of Cooperative Breeding 260
Bibliography 271
Index 287
Page ix
Foreword to the 1999 Edition
STEPHEN T. EMLEN
In 1930, a young Haverford College undergraduate found himself in Honduras as a
member of a small bird-collecting expedition from the Philadelphia Academy of Natural
Sciences. One day, while collecting his quota of bird specimens, he spotted a strange,
tentlike structure adjacent to a bulky bird nest in the forest. He correctly deduced that it
was a bird blind. In time, a second young man appeared and introduced himself as
Alexander Skutch. Skutch was working at the time as a plant pathologist for the United
Fruit Company. Having completed his routine chores for the day, he was now going to
spend the rest of the afternoon observing the behavior of Rufous-breasted Spinetails at
their nest.
When the two men discovered their mutual enthusiasm for birds and bird-watching,
Skutch invited the visitor into his blind. The visitor was John T. Emlen, Jr., my father,
who would later become a pioneering ornithologist and animal behaviorist at the
University of Wisconsin. John Emlen was utterly fascinated by what he saw that day. He
would later write in his diary: "Skutch had inserted a small paintbrush, dipped in yellow
paint, into the roof of the tunnel-like entrance to the bird's nest. As we watched, the
female came, incubated the
Page x
two eggs, and left with a neat, yellow stripe down her back, a readily distinguishable
marker for future individual recognition."
This story illustrates, in one small way, the collective debt that many of us owe Alexander
Skutch. By his example, he showed that studies of avian behavior could be a legitimate
aspect of ornithology and that by focusing on birds as individuals, one could discover
many previously unknown aspects of their social behavior. Alexander Skutch was a
pioneer, not only by studying bird behavior but also by bringing the uniqueness of
tropical birds to the attention of the world.
In 1935, long before the study of bird behavior was fashionable among North American
ornithologists, Skutch published a paper in the Auk, the scientific journal of the American
Ornithologists' Union, appropriately titled "Helpers at the Nest." In that paper, he
described his observations at the nests of three tropical species: Brown Jays, Banded-
backed Wrens, and Bushtits. He reported seeing individuals, in addition to the mated pair,
regularly bringing food to the nestlings or feeding the breeding female as she incubated
the eggs.
Skutch was years ahead of his time with these observations. It would be a quarter of a
century before others began reporting similar observations and thirty-five years before the
study of helping at the nest (now more commonly called cooperative breeding) would
become a major focus of evolutionary studies of social behavior.
At the time of the publication of this first helping paper, Skutch had already been living in
the tropics for seven years. In addition to his work for the United Fruit Company, he had
traveled through Panama, Honduras, Guatemala, and Costa Rica studying botany and
collecting plant specimens for herbariums and museums to the north. But his real interest
was birds, and he observed their behaviors with a patience, a passion, and a dedication
for detail unparalleled at the time. From his earliest travels to the present, a period
spanning some seventy years, Skutch has always been, first and foremost, an excellent
observer of natural history.
Despite his fascinating early observations, interest in the topic of helping behavior among
birds lay dormant until the mid 1960s. Then, two major advances in our conceptual
understanding of social behavior occurred that ushered the question of helping onto
center stage in the theater of avian research. One advance was ecological; the other was
genetic.
On the ecological side, ornithologists such as David Lack, Gordon Orians, Jerram Brown,
and John H. Crook argued convincingly that ecological factors play a major role in
shaping the forms of animal societies. For the first time, it became possible to forecast (in
advance of conducting a study) whether a particular species would be solitary or
gregarious, whether it would pair monogamously or polygamously, and whether it would
form year-round social groups. The study of bird behavior was on its way to becoming a
predictive science.
At about the same time, on the genetic side, evolutionary biologist William D. Hamilton
was coming to terms with the paradox presented by helping behavior: namely, how could
such seemingly altruistic behaviors evolve if those individuals exhibiting the unselfish
behaviors did not themselves breed? On the surface, helping behavior seemed to defy the
tenets of natural selection. Hamilton elegantly demonstrated in his theory of kin selection
that behaviors such as helping are indeed in a helper's selfish interest, as long as the
helper is a close genetic relative of the individual(s) it helps.
The reasoning is simple: a close ge-