CURRENT ORNITHOLOGY VOLUME 16

Current Ornithology

Editorial Board

C. Davison Ankney, University of Western Ontario, London, Ontario; Canada

Gregory F. Ball, Johns Hopkins University, Baltimore, Maryland

Steven R. Beissinger, University of California, Berkeley, California

Cynthia Carey, University of Colorado, Boulder, Colorado

Robert C. Fleischer, National Zoological Park, Washington, D.C.

Ellen D. Ketterson, Indiana University, Bloomington, Indiana

Patricia Monaghan, Glasgow University, Glasgow, Scotland

Theunis Piersma, Netherlands Institute for Sea Research {NIOZj, Texel and University of Groningen, The Netherlands

Irene M. Pepperberg, Massachusetts Institute of Technology, Cambridge, Massachusetts

Christopher M. Perrins, University of Oxford, Oxford, England

Stephen L. Rothstein, University of California, Santa Barbara, California

Ken Yasukawa, Beloit College, Beloit, Wisconsin

A Continuation Order Plan is available for this series. A continuation order will bring delivery of each new volume immediately upon publication. Volumes are billed only upon actual shipment. For further information please contact the publisher.

CURRENT ORNITHOLOGY VOLUME 16

Edited by

VAL NOLAN JR. Indiana University Bloomington, Indiana

and

CHARLES F. THOMPSON Illinois State University Normal, Illinois

SPRINGER SCIENCE+BUSINESS MEDIA, LLC

The Library of Congress cataloged the first volume of this title as foUows:

Current Ornithology.-Vol. 1-New York: Plenum Press, c1983-

v.: ill.: 24 cm. Annual. Editor: Richard F. Johnston. ISSN 0742-390X = Current ornithology.

1. Ornithology-Periodicals. 1. Johnston, Richard F. QL671.C87 598' .05-dc19

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©2001 Springer Science+Business Media New York

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Originally published by Kluwer Academic/Plenum Publishers, New York in 2001 Softcover reprint of the hardcover 1 st edition 2001

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CONTRIBUTORS

CHARLES R. BROWN, Department of Biological Sciences, University of Tulsa, Tulsa, Oklahoma 74104

MARY BOMBERGER BROWN, Department of Biological Sciences, University of Tulsa, Tulsa, Oklahoma 74104

AMBER E. BUDDEN, School of Biological Sciences, University of Wales, Bangor, Gwynedd, LL57 2UW, United Kingdom

PETER O. DUNN, Department of Biological Sciences, University of Wisconsin, Milwaukee, Milwaukee, Wisconsin 53201

RUSSELL GREENBERG, Smithsonian Migratory Bird Center, Washing­ton, D.C. 20008

JUHA MERILA, Department of Population Biology, Evolutionary Biol­ogy Center, Uppsala University, SE-752 36 Uppsala, Sweden

CLAUDIA METTKE-HOFMANN, Forschungsstelle fUr Ornithologie der Max-Planck-Gesellschaft, D-82346 Erling/ Andechs, Germany

BEN C. SHELDON, Edward Grey Institute of Field Ornithology, Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom

B. IRENE TIELEMAN, Zoological Laboratory, University of Groningen, 9750 AA Haren, The Netherlands

v

vi CONTRIBUTORS

FRAN<;ms vEZINA, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada

LINDA A. WHITTINGHAM, Department of Biological Sciences, Univer­sity of Wisconsin, Milwaukee, Milwaukee, Wisconsin 53201

JOSEPH B. WILLIAMS, Department of Evolution, Ecology and Organ­ismal Biology, Ohio State University, Columbus, Ohio 43210

TONY D. WILLIAMS, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada

JONATHAN WRIGHT, School of Biological Sciences, University of Wales, Bangor, Gwynedd, LL57 2UW, United Kingdom

PREFACE

The objective of this volume is to publish comprehensive, authoritative, and timely reviews of topics of interest to the general ornithological community as well as to students of other vertebrates. We believe that the seven chapters of this volume meet that objective admirably. They testify to the continuing need for a series that publishes papers dealing with any area of active research on birds, unconstrained by restrictions on depth and breadth of coverage and therefore on length.

The first chapter in this volume focuses on the least understood of avian social systems, coloniality. In Chapter 1, Charles R. Brown and Mary Bomberger Brown bring their extensive experience with colonial species to bear on what they regard as the central difficulty facing students of this second most common form of avian social organization. This is the inability to find generalizations that satisfactorily explain either its origin or maintenance. Following a review of earlier attempts to develop a general explanation, the authors describe the value of phylogenetic analyses that are designed to provide information on how often coloniality has evolved. The authors point out that repeated evolu­tion of coloniality among different lineages suggests that it is a response to particular ecological conditions. They cast a skeptical eye on the widely held belief that coloniality is a result of limitation of nest-sites and suggest a number of approaches to test this hypothesis. In their discussion of the various costs and benefits of coloniality that have been identified, the authors distinguish between causative factors that first led to the evolution of coloniality and maintenance factors that have contributed to its continuance. Their consideration of costs and benefits leads to the conclusion that many of the conventional views surround­ing the origin and maintenance are based on much less evidence than is generally appreciated. This paucity of evidence and the results of

vii

viii PREFACE

phylogenetic analyses lead them to warn that a general explanation for the origin of coloniality is unlikely to emerge. To identify factors con­tributing both to origin and maintenance, they urge future studies to include (1) measurement of reproductive success in colonies of different sizes, which combines the effects of both costs and benefits, (2) investi­gation of causes of variation in colony size, and (3) documentation of phenotypic and genotypic differences among individuals in colonies of different sizes.

Amber E. Budden and Jonathan Wright's review (Chapter 2) of beg­ging by nestling birds is an important analysis of the many theoretical and empirical studies of conflicts between parent and young, parent and parent, and offspring and offspring (intra-brood and across-broods). These interactions usually occur at a fixed location, the nest, and they offer an unusually straightforward opportunity to observe, manipulate, and quantify critical activities at definable and more or less standard­ized stages of life. For these reasons, possibly, begging has interested a variety ofresearchers: modelers and game theoreticians, theoretical and empirical students of signaling and communication, population and developmental biologists, and behavioral ecologists interested in such problems as mating and social systems. Focus on signaling has led to an emphasis on trade-offs between costs (expenditure of energy, attraction of predators) and benefits, with ramifications into honesty of signaling, brood size and volume of sound, extent and effects of within-brood relatedness (including signaling by brood parasites), and many other subjects. Somewhat overlapping the approach that stresses signaling as critical to the evolution of begging is the view that begging originated as a mechanism for prevailing in sibling competition, with parents simply taking advantage of information provided by the competition and using it on occasion as the basis for discriminating among the competitors. This complex and multi-faceted literature has been badly in need of analysis, organization, and the imposition of structure; and authors Budden and Wright have filled this need. They relate the purely theoretical literature, with its simplifying assumptions, to the empirical data and their complexities. They conclude their review with a discus­sion of the probability that nestlings learn to adjust their begging efforts to the expected payoff, i.e., with facultative behavior that presumably is related to resource availability and associated factors. They suggest that in this dynamic respect, begging may be analogous to foraging and that understanding begging may be advanced by bringing to bear insights derived from optimal foraging studies.

Intraspecific and interspecific variations in responses of animals to stimuli never previously encountered have interested comparative psy-

PREFACE ix

chologists and ethologists for decades. In their chapter on neophobia and neophilia in birds (Chapter 3), Russell Greenberg and Claudia Mettke-Hofmann analyze the extensive literature, both avian and non­avian, but do so from a neglected perspective, i.e., the ecological conse­quences of such responses. The authors argue that neophobia (aversion to the novel) and neophilia (the tendency to approach and explore it) are probably important driving forces in avian evolution: behavioral shifts arising out of new environmental experiences precede selection for adaptations that enhance fitness resulting from the shifts. A theme of this chapter is the theoretical importance of distinguishing between two competing hypotheses: the argument that neophobia and neophilia are simply opposite extremes of a one-axis continuum and the alternative hypothesis, espoused by the authors, that neophobia and neophilia are the products of motivationally independent systems, i.e., that both mo­tivational states can exist simultaneously and interact in the same indi­vidual. The authors describe and analyze methods for determining the relative importance of the two states and the complications introduced by such factors as hunger, details ofthe environment, and innate biases. A section on adult birds deals with familiarization, social facilitation (with attention to the possible role of dominance), and genetic and neurobiological bases of interspecific variation; it also reviews studies of the importance of sex, individual differences in temperament, and seasonal change. A section on juveniles describes the typical ontogeny of exploratory tendencies and behavior: highest toward the end of fledg­ling life, followed by canalization of behavior and a shift to neophobia. Many problems are most easily and fruitfully studied in naive individ­uals or those whose experience has been controlled, and research that follows the individual throughout life can explore the effects on adults oftheir early behavior and experience. Other topics covered are compar­ative (taxonomic, island vs. mainland species) and Greenberg's ecology­based Neophobia Threshold Hypothesis, which aims to synthesize many studies by relating environmental background to behavioral char­acteristics. A valuable summary emphasizes gaps in our understanding and, by asking twelve questions, points out future research possibilities. The chapter will stand as a valuable synthesis of a subject with far­reaching ramifications.

The investigator's ability to identify and associate individual par­ents and offspring makes birds excellent subjects for the study of quan­titative genetics of natural populations, the topic of Chapter 4 by Juha Merila and Ben C. Sheldon. During the almost fifteen years since pub­lication of the last review of field studies of avian quantitative genetics, the number of published works has soared, and this led the authors to

x PREFACE

set three goals for themselves. The first was to give an overview of the field, both in methodology and taxonomic coverage. The second was to provide a critical analysis of the strengths and weaknesses of different approaches that are used to study natural populations. In describing the methods available to estimate heritability and genetic correlation, Me­rila and Sheldon emphasize each method's assumptions and the conse­quences of measurement error. The third goal was to illustrate how avian systems could be used to study genetic variation within and among populations, thereby contributing to our general understanding of evolution and adaptation. A review of 167 studies, in which heri­tabilities or genetic correlations were measured in a range of traits , leads to the conclusion that avian research has contributed to conceptual advances that apply to a wide range of organisms. Despite these ad­vances in understanding, however, we still know little about the quan­titative genetics of sexually selected and life history traits. The impor­tance of considering confounding environmental and maternal effects on estimates of quantitative genetic parameters also receives attention, as do the consequences of extra-pair paternity. The authors conclude by pointing out that the goal of quantitative genetic studies is a better understanding of evolutionary trajectories of populations, and they de­scribe two approaches they regard as particularly promising for future research: modeling individual animals to make use simultaneously of all information in a pedigree, and integration of quantitative and mo­lecular genetic information. This chapter will be an important contribu­tion to quantitative geneticists, whatever their level of experience and degree of familiarity with the subject.

Since the discoveries that extra-pair fertilizations are widespread in birds and that the level of paternal effort varies considerably both across species and among conspecific individuals, the relationship between paternity and male care of offspring has attracted a great deal of atten­tion. The problem, treated here by Linda A. Whittingham and Peter O. Dunn in Chapter 5, is especially interesting because expenditure of time and energy on paternal care (e.g., incubation, feeding young) is gener­ally accepted as being incompatible with devoting time and energy to gaining fertilizations (mating effort). Each type of effort is expected to enhance male fitness, so understanding how and why males of different species, or different males of the same species (within or across popula­tions), or the same individual at different nesting attempts vary in their allocation of parental effort engages students with many interests, e.g., mating and social systems. The allocation problem cries out for model­ing, and many models have been produced. Similarly, because the pre­dictions of the models are in many respects amenable to empirical

PREFACE xi

testing, the number of field studies has grown rapidly in recent years. Results of this research often conflict, and Whittingham and Dunn have performed a valuable service by summarizing, evaluating, and synthe­sizing the theoretical literature and its various assumptions, pointing out what predictions can appropriately be drawn from various models and considering how these may be tested. Considerable attention is also devoted to empirical studies and to the many factors that can influence and confound their results. Two questions that are critical to any anal­ysis of the relationship between paternity and behavior are these: 1) Is the variation in paternal care random or non-random, and 2) can males assess the level of their paternity?

The authors conclude that all models predict that male parental care is influenced to some extent by paternity, but the nature, extent, and detectability of paternity may differ fundamentally. For example, even if males of the population cannot assess their paternity at a nest, they may have evolved the trait of devoting more care to first broods of the season than to second, if levels of extra-pair fertilization are generally higher at second nests. Males that can assess the level of their paternity within the individual brood may adjust their parental effort accordingly, provided that the benefits of doing so outweigh the benefits of focusing energy on mating effort. Studies of cooperatively breeding birds are especially useful in getting at the complexities of these relationships. A conclud­ing paragraph presents the authors' identification of questions espe­cially worthy of future study; e.g., forms of male care other than the feeding of nestlings (incubation and brooding) have been largely ne­glected. It also identifies the social systems whose study is most likely to elucidate different kinds of problems.

Joseph B. Williams and B. Irene Tieleman's study of physiological ecology and behavior of desert birds (Chapter 6) is a valuable review of an important subject. In addition to their desire to assemble and analyze current knowledge, to which they have themselves made a large contri­bution, the authors were motivated by skepticism of the traditional view that desert birds lack unique adaptions for life in their extreme environments. High ambient temperatures (sometimes alternating with cold nights), aridity, and in most cases unusually low primary produc­tivity are characteristics of deserts, defined loosely to include extensive areas of the world that are semi-arid, arid, and hyperarid. The authors briefly catalogue and describe these areas and their geological histories, both paleodeserts and extant. -Following descriptions of studies (and methods) pertaining to each of the three problems covered-energy balance, water balance, and thermo-regulation-they perform statistical analyses comparing desert and non-desert groups. In most cases, their

xii PREFACE

statistics indicate that the two comparison groups differ in ways that one would intuitively predict. The basal metabolic rates of many desert birds is lower than that of selected non-desert counterparts, as is their energy expenditure (field metabolic rate). With respect to water balance, recall that the rate of mass-specific water loss in birds exceeds the rate in all other terrestrial vertebrates. Given the limited access of desert birds to water, major physiological problems are dehydration and loss of body mass. On these subjects the authors examine an extensive literature dealing with body composition, renal structure and urine concentration, evaporative water loss, and field water flux. Their review of thermo­regulation encompasses physiological mechanisms, e.g., metabolism, evaporative heat loss, and problems associated with optimizing the tradeoff between the benefits of selecting a diet relatively high in water content and the cost (low energy content) that characterizes such food. The thermoregulation section will be especially interesting to some readers, because it deals with behavior as well as physiology. Various behaviors, for example, minimize contact with very hot substrates, while others maximize contact with substrates, including some spots prepared to be cool by the birds themselves (e.g., scrapes). Removal from harsh environments, nomadism and migration, are ultimate behavioral mechanisms that solve desert problems, but perhaps this disqualifies such birds for inclusion in the focal category. The authors summarize their analysis with the argument that they have challenged the tradi­tional no-special-adaptations view, which relies heavily on birds from semi-arid North American environments: these are about 15,000 years old. Some desert birds, they conclude, probably have evolved mecha­nisms that lower both metabolic rates and evaporative water loss. Their work should stimulate and provide guidelines for much new research.

Few authors have considered how intraspecific (interindividual) variation in reproductive energy expenditure bears on fitness-related traits, which is the topic of Tony D. Williams and Frangois Vezina (Chapter 7). The possible relationships between daily energy expendi­ture and reproductive output are numerous and varied, and these rela­tions are important from an evolutionary perspective. But measuring the energy expenditure of individuals is fraught with problems of pro­cedural and measurement errors. To address the general questions of whether reproduction is energetically costly and how energy expendi­ture varies for different breeding activities, the authors use studies that have employed the doubly-labeled water technique to estimate daily energy expenditure. They do so, however, in the context of evaluating potential sources of error in relation to the measured magnitude of individual variation found in field studies. Their review of published

PREFACE xiii

studies of energy expenditure lends support to the conclusion that expenditure during the chick-rearing stage of the breeding cycle is not exceptionally high compared with expenditure during other stages. In their conclusion, they sound two notes of caution. First, they encourage future studies to evaluate the assumptions that are the bases of research on relationships between measures of daily energy expenditure and reproductive effort and costs. Second, they call attention to the potential for substantial measurement error in the doubly-labeled water tech­nique, a problem that they argue needs to be addressed in each study. Future researchers will be particularly well-served by the authors' iden­tification of the possible relationships (not always positive ones) be­tween interindividual variation in daily energy expenditure and repro­ductive output, as well as by their detailed analysis of the pitfalls in measuring energy expenditure in free-ranging birds.

* * * We plan to continue our procedure of requiring authors to submit

prospectuses of projected papers; a model prospectus is available upon request to anyone who is interested. Relying on the prospectus and in consultation with our Editorial Board we decide whether a paper is likely to be suitable for Current Ornithology, inform the author, and arrange a time schedule for submission of a final draft. Manuscripts are sent to reviewers, but because the prospectus process is an effective filter, the normal outcome of the review process is refinement and revi­sion rather than rejection of the paper. The importance of our Editorial Board, whose names appear facing the volume's title page, cannot be overemphasized: each member's evaluation of a prospectus is sent to the author and usually includes helpful suggestions about scope and per­spective, organization and emphasis, overlooked references, and simi­lar matters. We thank Board members for their invaluable contributions to this volume. We also thank Marjorie Young for her tireless, dedicated, and reliable handling of drafts, re-drafts, correspondence, etc.; her help was indispensable.

Suggestions, inquiries, and other correspondence will be wel­comed and should be sent to Charles F. Thompson at wrens@ilstu.edu or to Val Nolan at vnolan@indiana.edu. Those who prefer to use conven­tional mail will find our institutional addresses on the title page. For a cumulative list of titles and authors of papers in earlier volumes of Current Ornithology, see Kluwer Academic/Plenum Publishers' web page at http://www.wkap.nl.

Val Nolan Jr. Charles F. Thompson

CONTENTS

CHAPTER 1

AVIAN COLONIALITY: PROGRESS AND PROBLEMS

CHARLES R. BROWN AND MARY BOMBERGER BROWN

1. Introduction ........................................... 1 2. Historical Background. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Phylogenetic Analyses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Limitation of Breeding Sites ............................ 7 5. The Costs and Benefits of Coloniality .................... 10

5.1. Ectoparasite and Disease Transmission .............. 12 5.2. Misdirected Parental Care .......................... 14 5.3. Predation-Related Effects ........................... 21

6. Social Foraging and Coloniality ......................... 28 6.1. The Information Center Hypothesis ................. 29 6.2. The Recruitment Center Hypothesis ................. 32 6.3. Spatial Concentration and Local Enhancement ....... 34 6.4. Competition and Depletion of Food ................. 36

7. Reproductive Success and Habitat Selection. . . . . . . . . . . . . . 38 7.1. Mean Reproductive Success in Relation to Colony

Size .............................................. 39 7.2. Using Reproductive Success to Select Breeding Sites 46

8. Sexual Selection and Coloniality ........................ 51 9. Variation in Colony Size ................................ 54

9.1. Ideal-Free Distributions and Local Resources. . . . . . . . . 55 9.2. Phenotypic and Genetic Differences among

Individuals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 9.3. (In)stability of Colony Size ......................... 60

xv

xvi CONTENTS

10. Prospectus............................................. 62 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

CHAPTER 2

BEGGING IN NESTLING BIRDS

AMBER E. BUDDEN AND JONATHAN WRIGHT

1. Parent-Offspring Conflict. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 2. The Importance of Signaling ............................ 84

2.1. Begging as a Signal ................................ 84 2.2. The Models ....................................... 85 2.3. The Cost of Begging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

3. Begging Signals ........................................ 92 3.1. Defining Begging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 3.2. Is Begging Influenced by Nestling Condition? ........ 94 3.3. Which Cues Do Parents Use? ....................... 96

4. Begging as Competition among Nestmates ................ 98 4.1. Sibling Competition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 4.2. Brood Hierarchies ................................. 98 4.3. Brood Parasites ......................... :. . . . . . . . . . 100

5. The Importance of Offspring Sex ........................ 102 6. The Role of Biparental Care ............................. 104 7. An Alternative Perspective. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

7.1. Begging as Foraging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 7.2. Do Nestlings Learn? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

8. Conclusions ........................................... 111 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

CHAPTER 3

ECOLOGICAL ASPECTS OF NEOPHOBIA AND NEOPHILIA IN BIRDS

RUSSELL GREENBERG AND CLAUDIA METTKE-HoFMANN

1. Introduction........................................... 119 1.1. The Implication of Novelty Responses and

Exploration: A Brief Overview ...................... 119 1.2. Definitions ......................................... 124 1.3. Costs and Benefits of Neophilia and Neophobia ...... 125 1.4. Costs and Benefits within Two-factor Models of

Exploration and Neophobia. . . . . . . . . . . . . . . . . . . . . . . . . 127 2. How Neophobia and Neophilia Are Studied .............. 129

CONTENTS xvii

2.1. Assessing Neophobia and Neophilia . . . . . . . . . . . . . . . . 129 2.2. Teasing Apart Neophobia, Hunger, and Neophilia ... 130 2.3. The Nature of Novel Stimuli. . . . . . . . . . . . . . . . . . . . . . . 131 2.4. Among-Object Variation in Novelty Responses ...... 133 2.5. Innate Bias in Novelty Responses .................. 134

3. What Determines the Intensity of Neophobia and Neophilia in Adult Birds ............................... 135

3.1. The Process of Familiarization. . . . . . . . . . . . . . . . . . . . . 135 3.2. The Dynamics of Exploration and Neophobia. ...... 139 3.3. Social Facilitation and Novelty Responses .......... 141 3.4. Consistent Individual Variation in Neophobia. . . . . . . 145 3.5. Genetic Basis for Intraspecific Variation ............ 146 3.6. Neurobiological Basis for Novelty Responses. . . . . . . . 148 3.7. Neophobia and Gender............................ 148 3.8. Novelty Responses and the Socioecological Niche. . . 149 3.9. Facultative Changes in Novelty Responsiveness ..... 150

3.10. Seasonal Changes in Costs and Benefits of Novelty Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

4. Exploration in Juvenile Birds ........................... 152 4.1. Overview ........................................ 152 4.2. What Do Juvenile Birds Explore? . . . . . . . . . . . . . . . . . . . 154 4.3. Object Manipulation in Young Birds: Familiarization

or Practice ....................................... 155 4.4. The Effect of Diverse and Depauperate Early

Environment on Adult Neophobia ................. 157 5. Comparative Studies of Neophobia and Exploration.. .. . . . 158

5.1. Taxonomic Comparisons .......................... 158 5.2. The Neophobia Threshold Hypothesis. .. ........... 160 5.3. Neophobia and Neophilia in Island Populations. . . .. 166

6. Conclusions and Future Directions ...................... 167 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

CHAPTER 4

AVIAN QUANTITATIVE GENETICS

JUHA MERILA AND BEN C. SHELDON

1. Introduction ............................................ 179 2. Components of Phenotypic Variation .................... 181 3. Tools of the Trade. . . . . . . . . . . . . . . .. . . . . . .. . . . . . . . . . . . . . . 183

3.1. Parent-Offspring Regression. . . . . . .. . . . . . . . . . . .. . . . 184 3.2. Full-Sib Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

xviii CONTENTS

3.3. Half-Sib Analyses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 3.4. Realized Heritability .............................. 193 3.5. Genetic Correlations .............................. 198 3.6. Measurement Error and Repeatability .............. 198

4. Empirical Data ......................................... 200 4.1. Heritabilities ..................................... 201 4.2. Genetic Correlations .............................. 209 4.3. Empirical Estimates: Conclusion ................... 212

5. Maternal Effects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 5.1. Adaptive Maternal Effects ......................... 214

6. Extra-Pair Paternity .................................... 215 6.1. Extra-Pair Paternity Detected by Heritability ........ 216 6.2. Consequences of Extra-Pair Paternity for Avian

Quantitative Genetics ............................. 217 6.3. Uses of Extra-Pair Paternity for Quantitative Genetic

Analysis ......................................... 218 7. Quantitative Genetics of Fitness. . . . . . . . .. . . . . . . . . . . . . . . . 219 8. Genotype-Environment Interactions. . . . . . . . . . . . . . . . . . . . . . 222 9. Genetic Basis of Population Differentiation .. . . . . . . . . . . . . . 228

10. Applications of Quantitative Genetics to Avian Evolution 233 11. Further Prospects ...................................... 236

11.1. Animal Models in Avian Quantitative Genetics.... . . 236 11.2. Integration of Molecular and Quantitative Genetics. . 238

12. Conclusions ........................................... 240 Appendix ............................................. 241 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

CHAPTER 5

MALE PARENTAL CARE AND PATERNITY

LINDA A. WHITTINGHAM AND PETER O. DUNN

1. Introduction ........................................... 257 2. Theoretical Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262

2.1. Assumptions of Models ........................... 263 2.2. General Predictions from Models .................. 264 2.3. Does it Pay to Reduce Male Parental Care When

Paternity is Low? ................................. 266 2.4. Male Parental Care and the Shape of Cost and

Benefit Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 2.5. Female Compensation and Evolutionarily Stable

Strategy Models .................................. 270

CONTENTS xix

2.6. ESS Models 270 2.7. Dynamic Models ........ , . . . ... . . . . . . . . . .... . . .. . . . 273 2.8. Conclusions from Models .......................... 274

3. Field Studies: Testing Predictions and Assumptions ...... 275 3.1. How Does Paternity Vary? .......................... 276 3.2. Can Males Assess Paternity? ........................ 278 3.3. What Are the Costs and Benefits of Reducing Care? . . . 281 3.4. Confounding Factors in Field Studies ............... 287 3.5. Conclusions from Field Studies. . . . . . . . . . . . . . . . . . . . . 288

4. Interspecific Analyses .................................. 289 5. Conclusions and Future Directions ...................... 292

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

CHAPTER 6

PHYSIOLOGICAL ECOLOGY AND BEHAVIOR OF DESERT BIRDS

JOSEPH B. WILLIAMS

1. Introduction ........................................... 299 1.1. Comparative Methods .............................. 301 1.2. Deserts of the World ............................... 303 1.3. Avian Evolution ................................... 306 1.4. Paleodeserts ....................................... 307

2. Energy ................................................ 308 2.1. Basal Metabolic Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308 2.2. Field Metabolic Rate ............................... 310

3. Water ................................................. 312 3.1. Water Deprivation ................................. 312 3.2. Metabolic Water ................................... 313 3.3. Renal Structure and Function. . . . . . . . . . . . . . . . . . . . . . . 314 3.4. Evaporative Water Loss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 3.5. Field Water Flux. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

4. Thermoregulation ...................................... 330 4.1. Responses to High Ta .............................. 330 4.2. Macroclimate...................................... 333 4.3. Microclimate ...................................... 336 4.4. Mobility .......................................... 340

5. Optimization Processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341 6. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

xx CONTENTS

CHAPTER 7

REPRODUCTIVE ENERGY EXPENDITURE, INTRASPECIFIC VARIATION

AND FITNESS IN BIRDS

ToNY D. WILLIAMS AND FRAN~OIS VEZINA

1. Introduction ........................................... 355 1.1. Intraspecific (Interindividual) Variation. . . . . . . . . . . . . . 356 1.2. Doubly-Labeled Water and Other Methods for

Measuring Energy Expenditure...................... 358 1.3. Aims, Objectives, and Limits ....................... 360

2. Is Reproduction Energetically Costly, and at What Stage Is It Most Costly? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

3. Intraspecific Variation in Daily Energy Expenditure: Biological Variation or Measurement Error? .............. 363 3.1. Measurement Error ................................ 363 3.2. Handling or Treatment Effects ...................... 371 3.3. Individual Variation in DEE from Field Studies

Relative to Measurement Error. . . . . . . . . . . . . . . . . . . . . . 372 4. Repeatability of Daily Energy Expenditure Measurements 374 5. Individual, Environmental, and Activity-Related Correlates

of DEE ................................................ 378 5.1. Individual Attributes............................... 379 5.2. Environmental Factors ............................. 380 5.3. Activity-Related Variation .......................... 382 5.4. Summary ......................................... 382

6. Metabolic Rate and Body Mass: Intraspecific versus Interspecific Scaling ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 6.1. Intraspecific Variation in Body Composition and

Metabolic Rate .................................... 385 7. Relationships between DEE and Measures of Reproductive

Effort or Fitness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 7.1. Timing of Laying, Egg Size, and Clutch Size ......... 390 7.2. Offspring Growth and Quality ...................... 391 7.3. Brood Size and Provisioning Rate ................... 391 7.4. Costs of Reproduction: Survival and Future Fecundity 392 7.5. Summary ......................................... 393

8. Conclusions and Recommendations for Future Research . . . 396 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399

INDEX..................................................... 407