Chapter 10

UCLA (1981-2007), Birds

I inherit two budgies-a new direction of research

In 1981, almost by accident, my research took another sharp turn, this time toward studying birds. I had inherited 2 small parrots, known as Budgerigars, also affectionately called "budgies." In my career to this time, my interest in birds, other than the short excursion into working with roadrunners, had been essentially nil. My living in proximity to these budgies, however, open my eyes to a vast, intriguing, new world of interest. Although my other affairs continued unabated - teaching, mentoring graduate students, studies in symmetry, etc., my non-mathematical research interests turned exclusively to birds, and there, and in peripheral studies to which they led, they remained until this day, although the experimental studies terminated in 1998, when I lost the use of experimental facilities.

I adopted precisely the same rationale in my avian studies as I had in my studies of mammals, namely, monitoring everything that transpired. For birds, however, this entailed a completely different approach. Small mammals generally are highly secretive, so that all monitoring must be non-intrusive. Moreover, they are terrestrial, so that automatically keeping track of their locations in enclosures, presents no insurmountable problem.

Birds, on the other hand, are much less secretive, and automatically keeping track of their locations presents several problems. Accordingly, to get the same amount of information from birds as from mammals required including the technique of direct observation, together with some of the other monitoring methods I already had in place for mammals.

I began my avian studies at home with initial small groups of captive-born Cockatiels (Nymphicus hollandicus), Budgerigars (Melopsittacus undulatus) and Peach-faced Lovebirds (Agapornis roseicollis). My plan was to observe these birds continuously in their open nest bowls and partially transparent nestboxes throughout their periods of activity. Inasmuch as I also was carrying out complex calculations related to my symmetry studies during this period, I could be present at almost all times, when not at UCLA for classes, seminars, or Dept. business. I sat in an armchair, about 6 feet distant, in full view of the birds. With this arrangement, the birds soon became accustomed to my presence.

However, the advantages of my near presence to the transparent nestboxes and open nest bowls, was not that the birds occupying them were unaware of my presence, and the fact that they were being observed. They were no less wary and aware of such matters when they were in Plexiglas sided nestboxes and open nestbowls than when they were outside of them in the enclosures. The advantage was that I could watch all their activities at times when they were fully occupied with each other and the eggs or young, without my having to move or otherwise intrude upon them.

My studies over the next 7 years led to my writing a book on the results, titled, "Lovebirds, Cockatiels, Budgerigars, Behavior and Evolution," published in February 1987. The studies are best introduced as follows, excerpting largely, but selectively, from the book's Introduction, in which complete references are given.

Throughout the ages, birds have attracted Man's keenest attention. They have become both the best known group of organisms and the one for which our knowledge of distribution is most extensive. Man also has become more susceptible to the charms of birds than to those of any other creatures. As Mayfield has observed, Ornithologists usually have been captivated by birds long before they thought of themselves as biologists, differing in this regard from their colleagues, few of whom came to science through their love of fruit flies or rats.

Birds are the primary agents of insect control throughout the world. Without their contributions, the earth would become virtually uninhabitable for us. The ill effects of a diet of polished rice on domestic fowl in 1896 led to the discovery of vitamins, and Louis Pasteur's development of the first vaccine for cattle anthrax originated from his investigation of fowl cholera.

Darwin's studies of the Galápagos finches played an important role in the development of his thoughts about natural selection, and the  remarkable complexity and sophistication of his thinking are revealed particularly well in his discussions of sexual dissimilarities and sexual selection in birds. Many recent refinements in evolutionary  theory derive from field studies of birds. Nut dispersal by Blue Jays is believed to have been the facilitating mechanism for the phenomenally rapid North American postglacial northward advance of oak trees.

Birds as key indicators. Because they frequently appear to be more sensitive or vulnerable than other vertebrates to environmental contaminants, birds often are regarded as key indicators of subtle changes in the ecosystem. Certainly they are the most commonly used vertebrates for this purpose. Birds gave the first alert to the dangers of DDT, and continue to expand our understanding of how environmental changes affect many forms of life. Birds provide a "window" through which both laymen and scientists can learn of their kinship to other animals. With each question answered about the behavior of these delightful, intriguing creatures-how and why they do what they do-we achieve a better understanding of ourselves.

Many biologists have long regarded birds as the best organism for exploring process and form in the biological realm. Students of birds have made significant and often pioneering contributions to nearly all aspects of biology: to embryology; to immunity; to the study of visual mechanism; to behavioral and population endocrinology; to island biogeography; to behavioral ecology; to community ecology; to studies of long distance migration; to theories of sexual selection and speciation; to the adaptive significance and evolution of mating systems; to evolutionary morphology; to the neural basis for learning; and to social behavior. It would not be an exaggeration to say that birds have been the principal subjects for studies in most of these areas.

Birds favored for behavioral studies. Birds have been the greatest favorites in studies of animal behavior as shaped by natural selection, and they continue to be studied intensively by a great number of workers. In fact, these studies made such rapid progress that most of our knowledge of animal behavior derives from them. The principal exception has been our knowledge of the genetic foundations of behavior, in which studies of fruit flies, some fishes, and rodents have led the way.

There are many reasons for favoring birds: they are numerous and widespread; they are small and easy to observe in confinement and in the field; they are easy to handle and care for; they are in the main day-active; their sensory capacities bear similarities to ours, and their social behavior depends primarily on visual and auditory signals; their moods are more readily susceptible than those of any other organism, many species possess large repertoires of striking, easily recognizable "instinctive" movement patters or displays; and they have developed some of the most spectacular adaptations to changing environmental conditions, so that many types of life histories and many variations among behavioral themes are found among them.

In addition: many birds exhibit extensive physical and behavioral sexual differences; birds have developed some highly advanced form of reproductive behavior, for example, their richness and variety in parental care patterns; the life spans of most species is optimal for many studies; many of the social institutions related to marriage and familial behavior in Man find their counterparts in the behavior of birds, by far the most monogamous of organisms; and birds have a great learning ability and respond in an intelligent manner in many types of tests, in fact, they surpass many mammals in some respects.

Parrots

Just as birds have attracted the greatest general interest and are the most popular pets, members of the "wondrous parrot family"-330 or more species-have; long been the most popular birds. More species of parrots (members of the Order Psittaformes) probably have been habituated and reared in captivity than those of any other avian group.

Outstanding vocal mimicry by parrots. The principal basis for the popularity of parrots, of course, is their outstanding vocal mimicry. Taken in combination with their manipulative versatility, their beauty of plumage, their exceptional intelligence among birds, the fascinations of their complex, varied, and challenging behavior, and the "uplifting experiences" and "joyous company" that they afford, it is easy to understand the well nigh irresistible attractions that parrots have for most people who become closely acquainted with them.

On the other hand, parrots have not enjoyed a comparable favoritism with students of birds. Despite their exceptional vocal mimicry, their songs are comparatively simple. Not only is their courtship behavior also simple, it is difficult to observe in the wild. Little of their brooding behavior had been studied before the present work (as they are hole-nesters), their evolutionary relationships (with other birds and with each other) are obscure and often a matter of guesswork, and the fossil record is poor. Even in confinement, there had been few previous studies of their behavior, most notably those of Dilger with lovebirds and Brockway with Budgerigars.

Laboratory studies and "what can happen." Not long ago many students of behavior and ecology were inclined to regard results contained with confined animals as artificial and distorted. Thus, one heard: only under free, natural conditions can one observe normal behavior in its full complexity and significance; do the processes observed in the laboratory relate in any way to what goes on in the field?; all behavior, including learning must be studied under natural conditions, for only in this way can its adaptive value be presumed to be assessed; and we do not want to depend on museum-bound theorists and interpreters who are not in touch with the living organism in its natural setting. Some field workers in the sociobiology of birds even oppose field experiments that are 'controlled,' and find the idea "quite unsettling."

[The reader might get the impression that I confined my studies of behavior to the laboratory. Actually, I did not. Not only had I had field experience as a youth -recall my expedition to Mexico and summers in camps-but all but 3 of my behavior and ecology Ph.D. thesis students worked exclusively in the field. Their study animals included sea otters, spinner, common, stripped, and bottle-nose dolphins, California meadow mice, California white-footed mice, grasshopper mice, pack rats, `island foxes, Mohave ground squirrels, coyotes, Cooper's, red-tailed, red-shouldered, and sharp-shinned hawks, prairie falcons, and reproductive biology of canopy plants, and pollination biology. JLK]

Laboratory versus field studies. On the other hand, some workers took the attitude that only theoretical and experimental approaches were valid. According to one worker, "if you're not doing an experiment every moment, you're wasting time." These workers were inclined to ignore and wave aside the contributions of field ecologists as "old fashioned natural history," which is too descriptive to contribute much any longer, provides information that is so incomplete as to be of little value for broader purposes, and is a contemplative and reflective activity, sometimes deeply satisfying but always of value solely to the individual observer.

Although neither the field, laboratory, nor museum worker need any longer defend his approach (nonetheless, some workers feel that museum science is ebbing), I believe it is appropriate to discuss further the comparative strengths of laboratory and field studies, I take this view principally because one of the chief merits of laboratory studies seems not yet to have been aired adequately in the literature; many of the findings presented here have precisely this merit.

What does happen versus what can happen. The comparative aspect that I would like to emphasize is that the most one hopes to find out from studies in the wild is what does happen; in the laboratory one can aspire to learn much more. One is able to explore in detail what can happen. In the wild, one merely gets "snapshots" in time-one finds out how animals behave over relatively brief periods in the conditions that prevail today. In the laboratory, one can examine the potentials of the animals to adapt to other conditions that might be encountered in the future or were in the past.

One also can explore variations in the ways different individuals respond to identical circumstances. The survival of a species may depend on the breadth of these differences. The greater the breadth, the greater the probability that a population will include individuals (genotypes) that will survive unfavorable conditions. In the arena of studies relating to learning and intelligence it has been asserted, I feel with good reason, that passive observations of animals in the wild do not necessarily reveal the full extent of their capacities. Efforts to determine the limitations of animals' capacities would have to be made in unnatural situations to see how far novel demands might be met.,

The information obtained in the laboratory often is more conclusive than even the most accurate record of what occurs in the wild.. In fact, it is not unusual for interpretation of well documented field studies to be inconclusive or controversial. For example, equivocal results often are obtained in studies of community ecology, particularly analyses of community structure and organization. This remains a controversial subject area in which it is seldom possible to perform experiments to test theories, and ecologists today are sharply divided in a controversy over the importance of competition between species in natural communities.

There have, of course, been some striking field successes. One such success has been the prediction of prey choices from optimal foraging theory. But despite the ease with which birds have been studied-because of their  conspicuousness and predominantly day active habit-avian population problems, such as the regulation of rates of reproduction-even only the determination of clutch size-have proved to be very difficult to solve. And although food supply and weather very likely are the two dominant environmental factors controlling avian populations, no definitive population theory either exists or appears to be in the offing.

In the absence of experiments, the ecologist tended to rely heavily on the results of comparative studies. Although these can provide useful insights when they are interpreted within a sufficiently broad context, the comparative approach has the weakness that the correlations that are found may be explained equally well by several alternative hypotheses. It is difficult to draw strong inferences even from the "natural experiments" that island communities seem to present. Accordingly, it has become increasingly imperative that field studies expand their use of experimental approaches-which already have come to be a powerful tool-and place a greater emphasis on the formulation of hypotheses that can be falsified.

Relict behavior. It will be evident in the following that most of the relict responses, that is, responses preserved from times long past, in the repertoire of Cockatielian behavior (some of which also were detected in lovebirds and budgies) could scarcely have been detected by studies other than experimental ones under controlled conditions. The circumstances that activated these responses in the wild may have ceased to occur with any significant frequency tens of millions of years ago, at the times when the ancestors of the birds abandoned ground nests and became hole-nesters.

Origin of the studies

To compare learning and behavior of parrots and mammals. The observations of previously unknown and little known behavior of parrots that are described here were almost purely adventitious by following up observations made in the course of breeding. Parrots were of particular interest to me because they are among the most intelligent of birds. My initial goal was to find out how parrots would compare with mammals in their learning ability and other aspects of their behavior, as assessed in light preference tests. In these tests the birds, themselves, perform the manipulations that directly control the ambient light levels to which they are exposed during activity and rest.

With this objective in mind I acquired 3 pairs of Budgerigars, a pair of Cockatiels and a pair of Peach-faced lovebirds. These became the founders of my colony. It soon became evident that the lovebirds were by far the most suitable birds with which to begin. They are miniature "dynamos" of activity-in all their ways of moving about, manipulating objects with their feet, and interacting among themselves. They also are bold, exceptionally inquisitive, and are of ideal size for learning and preference studies in experimental enclosures.

One of my initial projects was to breed the birds to obtain a sufficient stock of individuals of known origin and experience. In these endeavors I was most successful, at first, with the lovebirds and Cockatiels. They reproduce very readily in single pairs. Budgerigar pairs usually require the stimulation provided by the company of 1 or 2 other pairs.

Avian research takes an unexpected direction. The course of my research, along the same lines as I had pursued with mammals--light-level preferences, influences of various light levels and artificial twilights-quickly was channeled in an unexpected direction, following the observation of unprecedented new facets of parrot breeding behavior. From the time of these initial observations, it became evident that a wealth of new information could be obtained about the behavior and evolution of these birds merely through detailed observations and simple experimental; manipulations. The findings appear to have significant implications for the evolution of avian reproductive practices, as well as indirect bearings on other aspects of avian evolution, particularly the origin of feathers and flight.

Remarks on the origin of avian flight. A few remarks on the origin of avian flight are appropriate here. There have been two major theories in this regard, pieced together mostly from skeletal evidence, preserved feathers of fossil birds and dinosaurs, aerodynamic considerations, and some observations of avian behavior. One theory is that flight evolved from gliding downward from heights in trees, the other, the "ground up" scenario in which avian ancestors running on the ground may have achieved greater speed and, eventually, lift by flapping feathered forelegs, evolving flight, so to speak, with a running start.

My approach to, and proposal for, the origin of flight differs from that of others in that the solution of this problem was not my goal. On the contrary, I was led to it by a series of clues from my studies that, inevitably, led to it. In other words, conclusions concerning the method of evolution of flight in birds were essentially 'forced on me' when the problem was approached from the point of view of relict avian reproductive behavior, combined with considerations of reproductive physiology.

Stated concisely, feather rudiments evolved partly for shielding of certain reptiles and their eggs from overheating by direct exposure to the sun, as parents covered and guarded ground nests in warm, moderate Mesozoic climates. Egg warming during the day was not by incubation, as reptiles are cold-blooded, but by climatic and surface heat (indirect and direct effects of solar radiation). True feathers and flight, I believe, evolved primarily as a consequence of the parental ancestors' need to guard their nests during the night from nearby perches in vegetation.

When the nests and eggs, at night, became at risk from predators, these parents initially jumped, later parachuted, down to protect them. During the night, before incubation was practiced, the eggs were warmed by both climatic heat and heat from the rotting vegetation employed to cover and protect them. Such rotting ground litter was much more prevalent then than it is today. These matters are treated further below.

Lengthy, continuous, close, observations. Studies of birds most frequently focus attention on readily approachable questions that give quick answers, and they usually are pursued with relatively large numbers of birds, most often during breeding seasons. Data on the activities and strategies of birds during non-breeding seasons are meager, probably on the theory that anything done then by a bird beyond surviving has little influence on its reproductive success in the spring. Only relatively infrequently have observers followed the behavior and interactions of individuals over long periods.

For example, it took 20 years of study to find out that the mortality of a sea faring gull depends on its age and sex. A sample of 234 dispersers over 11 years was required to show a strong inherited component for dispersal distance in the Great Tit. Also, it took the perspective of continuous 30-year studies of Bobwhite Quail to evaluate their responses to land use changes, management practices, and hunting. The latter showed, for example, that continuous harvesting stimulated productivity.

'Living' with birds. Since I practically lived with my birds, I was able to observe virtually every noteworthy occurrence from hatching on, sometimes in great detail, 9-12 hours per day, 7 days a week, for over 6 years. Individual birds and mated pairs were studied over periods of many months, in some cases for 4 or 5 years, including numerous successive clutches and broods, and stages of development from hatchlings to adulthood. From the results of these observations it became clear that the usual views of parrots that one obtains from mere time schedules of their development and care, and enumeration of their habits, are almost as drab and unrepresentative of their lives and interactions as are views of their skeletons for their living appearance.

In contrast to what is known of the nesting and breeding habits of most other groups of birds, information on parrots has been relatively unsystematic and generalized, even for common species. Because of their hole-nesting habits and consequent relative inaccessibility, most of what is known about parrots has had to be obtained from studies of confined birds. Since I sometimes was observing closely 2, or even 3, family groups over the same period, I had to be selective, concentrating my attention in areas where the least was known, and the behavior was least likely to be altered by confinement.

When I was able to observe the care of eggs and young continuously in the nestbox or open nest, sometimes from a distance of only 2 or 3 inches, it became evident that much of the past literature dealing with the behavior of these birds within the nestbox has bordered on mere guesswork. Rather than the mundane events that have been assumed from the piecing together of bits of unsystematic observations, much of what actually occurs is extraordinary, sometime involving behavior that was previously unknown in birds.

Relict responses - the essence of my findings. Through my close association with parrots and some very simple manipulations, I discovered an ensemble of relict responses that were unobserved before in any bird, as well as some other remarkable and previously unknown behavior. Certainly the least expected of these findings was perhaps the first experimentally elicited evidence with implications of the nesting and egg-care behavior of ancestral birds and their forerunners. This evidence appears to bridge a gap of well over 150 million years, even extending back to the times of birds' reptilian theropodan forerunners. Some of these findings emerged as a result of observing the influences of changes in light conditions - also the chief variable altered in my studies of mammals.

Neural circuits for archaic responses preserved. These findings call attention to the fact that the neural circuits of motor (muscle-controlling) programs for archaic responses have been preserved in the brains of vertebrates. Only the appropriate long-absent stimuli are needed to call these responses 'back to life.' The secret to activating them now lies not only in "where to look," as suggested recently by Provine, but also in 'how  to look.' The best known of these responses until now were the protective superficial reflexes and spinal automatism of Man (pages 523-526 in my book), most of which are vestigial (present only in rudimentary form) and are little known outside the disciplines of neurology and neurosurgery.

In the light of the existence of a mosaic of essentially unambiguous relict responses of Cockatiels, one may be unduly pessimistic to conclude that fossils provide the only evidence from which we can learn of adaptations of birds in past geological periods. Even the view that the conclusions of evolutionary studies of behavior can never be defended by anything better than indirect evidence, and can never be tested by experiment, is not unassailable.

Not only may vertebrate brains be the richest repository of tangible records of past behavior, the records retained there would appear to be in a much better state of preservation than any others. Using clues provided by the order in which relict responses and other egg-care behaviors appear or become accessible during Cockatielian breeding, I have been led to postulate that successive stages in the egg-care of Cockatiels recapitulate ('relive') the equivalents of successive evolutionary stages of the egg-care of their ancestors.

Number of maturing follicles also recapitulated. Similarly, I postulate that the number of maturing follicles that exist in the ovary during discrete follicular maturational stages of Budgerigars tends to recapitulate the number of maturing follicles and the numbers of eggs in the clutches of ancestors of Budgerigars during major evolutionary stages. There also are discrete maturational stages in other birds, as well as in many reptiles, and these also may tend to recapitulate the equivalents of ancestral reproductive states.

More generally, I would suggest that the phenomenon of follicular atresia (degeneration) during maturation of the ovaries, themselves, is the major evolutionary adaptation by means of which clutch and litter size have been reduced progressively in the course of evolution from distant prolific ancestral marine vertebrates. Subsequent to the appearance of my book on avian behavior and evolution, these considerations were published in the journal, Brain, Behavior, and Evolution (1988;32:340-352) under the title, "Presumptive Relict Reproductive Behavior in Small Parrots."

When one considers that the relict responses were detected merely by making close observations of normal behavior, and of the reactions of the birds to very simple experimental manipulations; that follicular maturational stages may give clues to ancestral evolutionary stages; that it is predicted that future successes expected in the study of avian morphology will be spectacular and will eclipse those achieved during the golden age of vertebrate morphology (structure and form); and that until recently much of the present and evolutionary relationships of birds have been misinterpreted and misunderstood to an astonishing degree (I remind the reader that references for these statements can be obtained from my book); then one may be justified in assuming that many rich veins of avian evolution remain to be probed.

To hazard an impression gained in the course of the present studies, I would suggest that many of the clues needed to reconstruct the evolution of birds and their behavior still are accessible to us. They may be preserved both overtly and covertly in avian relict reproductive responses and brains, cycles of maturation of avian reproduction in all of its aspects, the spectrum of avian reproductive habits, avian development from egg to adult, avian fossils, and certain of the like categories for reptiles, particularly cycles of maturation of reproduction, reproductive habits, and fossils. Though fleshed out avian ancestors are inaccessible, knowledge of their behavior and life styles may not be, and some of the latter well may find their equivalents among various living forms.

The reconstruction of avian evolution presented in Appendices II and III finds the most important channeling factors to have been the invasion of arboreal and aerial habitats by reptilian ancestors, onset and eventual waning of the warm, equable Mesozoic climatic regimes, transition from the employment of unattended nests buried at deep sites (60-90 cm), to attended nests, eggs and young at near-surface and surface locations, and the ready susceptibility of ovarian function to becoming modified. The value of this reconstruction lies not so much in its details, as in expanding our perspectives by bringing new considerations to bear on problems of avian evolution.

Anthropomorphisms. In interpreting the behavior of animals, I often feel justified to draw parallels with human behavior and emotions, and these parallels have become increasingly recognized in the literature (see Preface and Chap. 2). Nevertheless, I customarily describe and interpret behavior with guarded objectivity. To facilitate the detailed descriptions of social interactions that are given here I sometimes relax this caution. However, I usually indicate each such relaxation by setting off the concerned expressions with apostrophes. The parallels with human behavior that are implied bur not qualified in this way are intentional. In fact, there will be many occasions in the treatments of social interactions of Peach-faced lovebirds when the reader will be impelled to see our own behavior mirrored in the actions of the birds, and I do not hesitate to draw such parallels.

Reviews of Lovebirds, Cockatiels, Budgerigars, Behavior and Evolution Via personal correspondence:

This is actually several books under one cover. There is no doubt that you have enormous experience with the raising of these birds ....You are presenting a great deal of interesting information, much of it new, that should be of value to anyone who wants to study parakeets. Ernst Mayr, Harvard University

This book comprises a unique, exhaustive laboratory study of the behavior of Budgerigars, Cockatiels and Peach-faced Lovebirds. The studies and data from many sources of information on paleobiology, paleontology, geology, and paleobiogeography and climatology are integrated to produce a synthetic interpretation of many aspects of the origin and evolution of birds and of the roots of their behaviors. Inquiries are made into the patterns of development of locomotion, physiology, morphology and reproductive behavior.

The author has adopted a strict selectionist-adaptationist point of view, adhering to the tenets of synthetic theory of evolution. In this context, with a strong element of historical recapitulation, he has deduced from conserved habits and function, including endocrinology and breeding pathways, a remarkably comprehensive scenario of origins of many details [of behavior] observed in his laboratory. These are combined to produce consistent insights into the origins of these features in modern birds and their significance....The book is must reading for all interested in behavior and breeding in birds, and contains a wealth of information and ideas that will be of interest to all evolutionists. Everett C. Olson, UCLA

What an enormous amount of information....From the first look it is quite obvious that this book is a very important contribution to the study of behavior of parrot birds, about which so little is known so far. K. Immelman, U. of Bielefeld.

Congratulations on completing this monumental effort. Jared M. Diamond, UCLA.

Published reviews:

The vast amount of information offered is quite readable (perhaps over many long winter nights) and while some of it may be of interest to only the greatest enthusiasts the bulk of the material is absolutely pertinent to this of us who keep, maintain, and breed these birds....Under lovebirds: father-son relationships, feather-picking, perching for the night, pair bonds, night frights, plus a detailed history of the breeding of specific pairs which are identified by name. Under cockatiels: egg-care, breeding habits in the wild, courtship activities, laying of eggs elsewhere than in a nestbox, and allotment of feeding functions. Under budgerigars: behavior in relation to nestboxes, preliminaries to egg laying, molting and broodpatches....These are just a few of the topics chosen at random. There are hundreds of others and all of them provide a reference work that serious breeders and aviculturists will use almost daily.

Because of the massive size of the undertaking the author has done some special cross indexing so that readers seeking information on a particular topic will be able to easily locate it....etc., etc., etc.,...If you think I am making much of this procedure consider the fact that we are dealing with a book of over 1,000 pages and you will appreciate, as I did, anything the author did to organize such a wealth of information. American Cage Bird Magazine, October, 1987.

J. Lee Kavanau's book is a fascinating mixture of behavioral observations and intuitions concerning the nature of the behaviors of modern day psittaciform birds as well as their preavian and postreptilian ancestors. The book contains an extraordinarily large bibliography....and provides the reader with a virtual encyclopedia of background information concerning these interesting birds....Students of avian evolution and paleontology will be particularly intrigued by the author's principal thesis - that the behavior of ancestral forms can be inferred from what the author describes as 'relict' behaviors observed during laboratory studies of breeding, egg-care and other social interactions." [there follows a lengthy narration of some of the experimental results obtained, and alternate interpretations]

The book is filled with fascinating observations and hypotheses. Some are thought provoking and stimulating, but others are extremely speculative....the book will be of interest to many with a professional interest in the biology and behavior of psittaciform birds. In addition to an extensive review of the literature concerning avian biology and systematics, a great deal of information concerning animal husbandry is provided including diet, diagnosis of avian diseases and tips for breeding the birds. Steven Brauth, U. Maryland, Brain, Behavior and Evolution, Sept., 1988. [see, also, below]

This book is an ambitious attempt, on one hand, to touch upon almost every aspect of ornithology and, on the other, to give a detailed account of the behavior of three parrot species in captivity. Kavanau's specific goals seem to be to impress upon the reader the importance of behavioral studies that are carried out only in the lab, and to offer a hypothesis for the evolution of avian egg-care. The book is intended to appeal to anyone with an interest in birds, from aviculturists to academicians, particularly those who are interested in evolution....Embedded in the middle of it all is a reasonable hypothesis for the evolution of some aspects of reproductive behavior in birds.

Chapter 4 is the heart of the book. Here, using observations and experiments on Cockatiel egg-care, Kavanau arrives at a hypothetical sequence of stages in the evolution of avian egg-care. He also offers an interesting sequence of avian evolution, in general, tying together his views on evolutionary sequences involved in thermoregulation, insulation, care of young, mode of feeding and degree of arboriality....Even if one were to reject his hypothesis on the evolution of egg-care, his methods (using transparent nest box panels and extensive observations) make the data seem credible.

To the author's credit, the references here are very useful. In fact, anyone organizing an ornithology course for the first time might consider consulting this bibliography....there is a lot here that probably will be inaccessible to those without some background in biology....The information in Chapter 4 could have been the basis for an interesting journal article, whereas the detailed observations of behavior in his aviaries could have made interesting reading for aviculturists. Susan L. Berman, Holycross U., The Auk, July, 1988. [see, also, below]

....this book includes comprehensive discussions on the behavior, morphology, physiology, ecology, biogeography, and evolution of all birds....The author also strives to illustrate the validity and importance of laboratory studies in avian biology and the potential importance of aviculturists to studies of avian behavior....The basis for much of Kavanau's ideas on the evolution of incubation behavior and the use of cockatiels to illustrate relict behavior is his belief that behavior shows a high degree of evolutionary conservativeness. This chapter should provide much fuel for thought and some debate among students of avian evolution.

The scope of this book is impressive. The amount of information conveyed by the author is almost overwhelming. Nevertheless, the material is presented in an organized fashion and the text is well written....this book is a must for anyone seriously interested in avian evolution and should be in every major library. It may also be of use to aviculturists who are interested in a more scientific approach to aviculture. Finally, the book's detailed descriptions of captive bird breeding and experimentation provide numerous ideas for undergraduate and graduate research on captive birds. Stewart T. Skeate, Lees McRae College, Wilson Bulletin, Sept., 1989

....monumental in scope....much fascinating reading....many intriguing subjects....enormous project....excellent reference for experimental behavior or evolutionary science....looking forward to in depth study and to apply [the suthor's] concepts to....aviculture and avian veterinary medicine." G. J. Harrison, DVM, Bird World, Nov., 1987

A Synthesis of Early Avian Evolution

Many paleontological discoveries pertinent to the evolution of birds had appeared since my book's appearance in 1987. Additionally, my book and two following papers on evolution ["Presumptive Relict Reproductive Behavior in Small Parrots" (Brain, Behav, Evol. 1988;32:340-352); and "Conservative Behavioural Evolution, the Neural Substrate" (Anim. Behav. 1990;39:758-767)] seemed hardly to have been noticed by paleontologistts and other students of avian evolution.

For that reason I decided, early in 2003, to write another paper for journal publication (recall that this was suggested in the above book review by S. L. Berman) on early avian evolution, based on my studies of relict reproductive behaviors, taking into account the most recent paleontological findings and all pertinent knowledge in other fields. This resulted in a paper of such great length (over 26,000 words in its final version) and contentiousness that it took me years of submissions, revisions, and compromises (see Appendix II) finally to see it into print. It was published in August, 2007, in Scientific Research and Essays in a paper titled, "Roots of Avian Evolution: Clues from Relict Reproductive Behaviors." It is reproduced in Appendix III..

Additional findings

The findings treated above were by far the most significant-having led to a coherent, technically plausible scenario for avian evolution, consonant with paleontological findings. There were, however, many other observations along the way, some unprecedented, that I summarize in the following, categorized as to species. I am not aware that any of the cited behaviors was previously known, which is testimony to the inadequacy of approaches other than those I employed to study avian behavior. Inasmuch as all three of the species that I studied are very popular as pets, their behavior already observed by uncounted millions, it is highly unlikely that all of my findings concerning them are new.

The new findings, however, depended on the circumstances that I studied the birds in colonies of the same and different species, with given species sometimes intermixing at will, repeatedly experimented upon by removing individuals, adding individuals, changing locations of enclosure contents, changing enclosures, altering conditions and family composition, flighting in various combinations, removing and adding eggs, and every other conceivable opportunistic alteration all under the closest of observation throughout activity periods. Probably no other such intensive, long range, manipulative study of captive birds has been carried out. Nor could any junior faculty member afford to devote 7 years to such an enterprise. It was my good fortune to be working on another book at the same time, affording ample opportunity for side observations.

I regard the most significant findings of the work to be the relict behaviors, which depended on the detailed experimentation and close observations. My feelings were that future studies of captive birds, both with the goal of uncovering relict behaviors, and behaviors in general, would have to meet more exacting standards than the conventional 8-5 weekday schedule allows. On the contrary, reviewer S. E. Brauth (see above) claimed that:

Such details are unnecessary and, on the whole, tend to detract from the usefulness of the book.

But the utility of my modus operandi seemingly completely escaped S.L. Berman. In her review she found that:

The book reads like the earliest draft of a doctoral dissertation-the version that is seldom read by anyone but the writer. Each topic, even if relatively peripheral, is covered in excessive....detail.

One crucial lesson I have learned in my scientific, technological, and artistic endeavors is that success often depends on attention to detail, which rarely can be "excessive." Time and again, I would have missed vital points in my work, without unwavering attention to detail. This applies even to library research, where it is tempting to bypass a difficultly accessible work. I would agree that details may be superfluous in some unusual instances but, without prior knowledge of which instances, important clues that lead along fruitful paths elsewhere may be overlooked.

On the topic of attention to detail, this practice carries over for me even to the preparation of book indices, which are elaborate in all my books. Taking the present book as an example, in addition to the General Index, there are Common Name, Scientific Name, Author, and Reference Number indices. Examples of the detail in the General Index are given below for the three entries under "Egg," "Eggs," and "Eggshells." Without such detail much time can be lost seeking references and precise information and statements.

 

Egg  binding, 221,288  care, 23,117,131,575-581,   719-740   by ancestral birds,    hypothetical scheme,     401,402   burial, deep-to-shal-    luw transition, 593   competition, see    Cockatiels, egg care   contemporary, 444-    447, 575-581   covering, 527, 529,    550, 580, 581   covering response, 580    by dinosaurs, 450   directed searches,    393,428,430-433,453m    454, 481-485,504,513,    721,738,779-781   discarding defective    eggs, 455, 720,725     726,733,734   discarding overdue    eggs, 782,783   distant visual    search 393,428,430     433,453,454,466,     481-484,513,632   evolutionary stages    of, 436,440,441,443     456,466,479-481,     487,490,511,512   & insolation, 436,441    443-445,481,527,551   inspection of, see Eggs   & marble substitutes,    456-458   pre-avian, 442,446,527    & heat sources, 443,     444,446   recovered fostered    eggs, 469,479,486     494,511 rolling, 443 & hiding defective    eggs, 395,455,483,    484,492,513 rolling, 443 & hiding defective    eggs, 395,455,483,    484,492,513 routine searches, 393,    394,452-454,513,    721,722,739    chick present, 465    stereotypy of, 453,454   scratching with foot,394   shading, 404,550,575.581

Egg (cont'd)  care (cont'd)   shielding &/or guarding,    394,395,441-447,451,    477,480,491,511,551,    553,561,568,569,576,    628,718,740   single egg placates, 433,    452,453,501,518,572,    636,781   visual searches, 738,779-    781   wetting, 575,577,581  caruncle, 174,188-191.   668,698,699  losses, 540,546,556,557  production   & cutaneous secretions,    619    decline with age, 211    determinate vs indeter-     minate, 165,166    & diet, 288,289    energy expense of, 138    lability of, 595    precocial, 611    reversal of, 718    & vitamin B6, 223 Eggs,  abandonment, 368,730-   733,737,775,780,782,   783  cleidoic, 545, 546  color, 134  composition, 166  energy content, 165,   166,171  energy density, 166  equilibrium position,   445,476  exposure and vulner-   ability, 449,527  fossilized, 196  gaseous budget, 175  hydration, 171,544-546  inspection and manipula-   tion of, 176,177,451,455,    457,458,462,474,475,488   functions of, 475  kicking of, 782  multiply-yolked, 595  & nonbreeding birds, 411  number at commencement   of continuous incubation    176,177,441,442,444,    512,567,568,718,789

Eggs (cont'd) parchment  shelled, 155,   171,193,538,544-546  pecking open, 700.794,   795  protection of, 492,704  replacement clutch, 150  rigid shelled, 621,622  role of sight of, and of   contact with, 569-571  shape, 231,262  size, 134,260,624   & courtship feeding, 314   & nestling growth, 204  storage, 167,458,464,492  tactile stimuli from, 165  thin-shelled, 734  treatment by young, 794,   795  turning, 174,475   functions of, 475 Eggshells, 155,156,169  calcification, 156,157,161,   538,600,611  & Ca metabolism, 158,161  cap, 190  composition, 157  cracks in, 188  cuticle, 105,156,160-163   composition, 160  eating of, 746  evolution of rigidity, 155  formation, 155,156   & Ca metabolism, 158,161    involvement of intestinal     contents, 158,159 & medullary bone, 158  fungal penetration, 213  palisade or spongy layer,,    157,161,162  permeability and gaseous   exchanges, 155,156,162,169,    170,172,175,545,552  pigments, 157  pores, 161,162,176,538,545    covering of, 161    number and size, 169    protection froom infection,     162    removal of, 484    thinning of, 160    weight of, 194  withdrawal of Ca from, 159,    160,621

 

Peach-faced Lovebirds      

Introduction. Lovebirds are beautiful colorful bright-eyed, noisy gregarious little parrots. The confined birds have very engaging, expressive personalities and very colorful, lively, playful behavior, including comical antics and acrobatics. They are very hardy and long-lived. Peach-faced Lovebirds are the most popular species, requiring but a minimum of care and space. They are members of the largest (50-61 g), one of the most social and adaptable (least specialized), probably the noisiest, and certainly the most aggressive species in the genus.

Toe caressing. It was well known that one method of attack on other birds (whether lovebirds or other species) by Peach-faced Lovebirds, very aggressive by nature, is to bite the other's toes. I discovered that this behavior toward another bird's toes is at one extreme of their behavior. At the other extreme, such behavior toward toes is a method of friendly approach, supplication, and attention getting. in which the other's toes are caressed or nibbled gently, often repetitiously, until the goal is achieved. I also observed this behavior in Cockatiels, suggesting that it is of ancient origin. I did not observe it in Budgerigars, but there were few occasions, if any, on which the need for it might have arisen.

Mated female Lovebirds accept food from non-mates. The female of a lovebird pair was not known to tolerate the attention of a male other than her mate, even of a male broodmate. For example, neither she nor her mate will allow another male to perch beside her at any time. I found that there is one exception to this pair inviolate behavior. In certain circumstances. females will accept food from bachelor male siblings, both during incubation and brooding, and the female's mate may simply look on 'without concern' and even take turns. There is a close parallel to human behavior here. A lady will accept a dinner date with a man, with whom she would not tolerate intimacies. In essence, courtship feeding among birds, and dinner dates among humans clearly are less intimate interactions than grooming or sleeping side-by-side. The only previous suggestion of cooperative breeding among parrots is based only on sightings of more than a pair of birds at the nests of Red-sided parrots (Eclectus pectoralis) in Australia (Kavanau, 1987:332; all numbers in parentheses are page numbers in my book).

Hierarchy of dominance-copulating pairs attacked-egg-laying Cockatiel dominant. There is a hierarchy of dominance of interacting males from successive sibling broods. The male of a one brood is dominant over one of a later brood. For example, Cyrus was dominant over his broodmate, Cyrano, in all interactions, but subordinate to his older brother Jagatai in identical circumstances. On one occasion, Jagatai was housed for months with a mated pair of Cockatiels over whom he was dominant (as would be any adult Peach-faced Lovebird). He only occasionally 'bothered' them. Usually this occurred when they were copulating. A Cockatiel in her egg laying phase, however, will vigorously repel even a Peach-faced Lovebird. Unmated Cockatiels also were observed to 'bother' or otherwise interfere with copulating Cockatielian relatives, behavior otherwise, to my knowledge, not previously noted.

Female Lovebirds dominate all males - mandible gnashing in dark. It is well known that female Peach-faced Lovebirds dominate their mates; they also appear to dominate males outside their pair bond. Mandible gnashing by Lovebirds is very much in evidence after the lights are turned out for the night, when a chorus of dull rasping sounds can be heard from most colony members.

Highly conservative nature of avian behavior. A highly conservative nature of behavior applies not only to Lovebirds, Cockatiels, and Budgerigars birds, but to all the captive animals that I have studied. Numerous illustrative examples could be given. Quoting from my Science paper (1967;155:1628):

This comes about because, as mentioned above, some behavior of animals tends to be quite conservative. In this case, the first one or two wheels run may monopolize subsequent running. The same conservatism is seen in selection between sources if food and water, For example, in the enclosure of Figs. 2-11 & 2-12, paired food guns and water bottles usually are available (only one is shown). Although some variability is exhibited (as with other categories of behavior), typically only one food source is used. The other often is left untouched until the first is exhausted....Conservatism also applies to the use of water sources. To a degree such conservatism has survival value; animals that tend to confine their actions along already proved avenues have the highest likelihood of surviving.

In fact, my favorite illustration of the tendency to 'stick to' one water source emerged when I added table salt in daily increasing amounts to the water gun being used by a WF (white-footed) mouse. The animal persisted in drinking the increasingly salty water, gradually becoming dehydrated, before I restored fresh water to the gun. Unfortunately, I cannot locate the paper in which this incident is described.

Using Lovebirds, additional aspects of conservativeness of behavior emerged when the birds had the freedom to choose the enclosure they 'returned' to after being flighted. One Lovebird male, for example, repeatedly sought to return to his old enclosure, D (Fig. 10-1) after flighting, even though it contained two unfriendly older male siblings,. This was in preference to a more accommodating enclosure in which he could interact with a female with whom he was in the process of  pairing. I always found it necessary to catch him manually to return him to enclosure E (Fig. 10-1). He entered enclosure E voluntarily only when he followed his prospective mate as she went into it to feed (326).

Early morning behavior-a time of truce and courtship feeding. First, the very early morning period, before the lights are turned on, and for some time thereafter (and probably during the night, as well) are times of "truce" among Peach-faced Lovebirds. At those times overt aggression is strongly inhibited and may never occur. Second, the first activity in which breeding Lovebirds engage very early in the morning is feeding of the female by her mate. Much the same was found to be true of breeding Budgerigar pairs in breeding condition (335, 336). The disinclination also applied to aggression toward me. When I serviced the enclosures after turning the lights on, brooding hens were disinclined to attack me. But by the time I had replenished the water and was tending to the food, the same brooding hens might attack me vigorously. Later in  the day they usually rushed over and inflicted painful bites (649).

Female initiative. My results strongly support the conclusion that female Lovebirds often, or even characteristically, take the initiative during pair bonding. One unmated female challenged both heterosexual and homosexual pair-bond loyalties (337).

Nesting. The hen of a Lovebird pair is highly domineering as regards exploration and occupancy of a nestbox before the onset of laying, usually totally excluding her mate or allowing him only brief occupancy. This behavior often persists after the first egg is laid, but soon gives way to total tolerance, as the male frequently visits and grooms and feeds her.

Privacy - intolerance for young. One of the most impressive findings was noted repeatedly, and also applies to members of the other two species. In the presence of fledglings or juveniles of prior broods, Lovebird parents either seek out a secluded location most distant from the young for copulation, or they remain behind in the enclosure when the family is flighted, and cohabit in the absence of the young.

Intrusions ignored when feeding chicks. A common phenomenon among all three species, most strikingly exhibited by the most habituated individuals, was that when parents were engaged in care of the young, they tended to ignore my intrusions, as I sought to observe the proceedings closely. Care of the chicks had too high a priority to be interrupted voluntarily.

Neither extensive mutual grooming nor sleeping side-by-side essential in pair bonding. The bond between one Lovebird pair became established only on the basis of courtship feeding, short periods of contact in the male's enclosure and during flighting, very limited mutual grooming, and the continuous existence of channels for visual and vocal exchanges (337).

Condition of hatchlings - food processing. Hatchlings of Lovebirds are the most helpless of the three species studied. They usually cannot even sit up in a coordinated fashion and hold up their heads until they are about 7-9 days old. Several observations suggested that Lovebird hatchlings and young nestlings are not fed unless they solicit food by cheeping. Unlike the other two species, they are fed in any position in which the parent can deliver the food. Also, unlike the situation in the other two species, Lovebird hatchlings and very young nestlings appear to have the lowest priority for parental feeding.

The evidence suggests that preliminary processing of food for hatchlings is a prerequisite for Lovebirds, and that the bill clapping and respiratory sounds of the near-term embryo stimulate the parents to begin food processing. Inadequately processed food would account for the many occasions on which hatchlings cheeping for food were ignored by the parents, often at the very times that the parents were occupied with feeding of older chicks. It also would account for the delays of many hours before some cheeping hatchlings were fed. These results also suggest and imply that merely filtering normal crop contents between the tongue and palate to remove particulate matter does not provide food that is suitable for nourishing a hatchling, since otherwise the parents could provide suitable food at almost any time,

Role of the male in feeding of chicks. The Lovebird male plays a vital role in feeding nestlings. He husks and further processes most of the food, feeds it to the hen, cleans excess food from the bill of the female and bills and heads of the chicks during food delivery, removes large pieces of food from the mouths of both the hen and the chicks, delivers additional food to the hen via her tongue, even as she feeds the chicks and, last, but not least, feeds the hatchlings directly whenever the opportunity affords. In fact, the feeding of the chicks in the presence of both parents often, if not usually, is both competitive and cooperative, with each parent often brushing aside or pulling away the other's bill in an effort to gain access to the chick, either to feed or clean it. But the male always seems to give first priority to cleaning. These actions often occur with such great speed that lengthy, close observation usually is required to discern them. The hen is the main feeder throughout brooding, with the male's participation most intense in the early morning.

Protecting eggs and confined chicks. The Lovebird hen is by far the principal guardian of the eggs and chicks within the nestbox and enclosure. In general, the vigor with which the eggs and chicks were protected increased progressively as incubation and brooding progressed. Initial gentle nipping of my fingers as I serviced, soon became nips and painful bites. By the time chicks were present, it was typical of most parents to come charging back to the nestbox or nestbowl to protect the chicks and 'stand me off.'

Fledglings forcibly confined. As chicks approached fledging time within a nestbox, the parents forcibly confined them. She also 'herded' an escapee back to it. As the chicks became more persistent in their efforts to exit, considerable physical effort on the part of the parents sometimes bodily hurling the chicks back was required to keep them confined, A great deal of tumult of movements and sound was a characteristic accompaniment. Juveniles and older birds of previous broods were excluded from the nest and its vicinity, and attacked vigorously when they intruded.

Male principal guardian outside nestbox. The male is the principal guardian nearing the time of fledging and of fledglings outside the enclosure or nestbox. Before chicks were individually recognizable, and sometimes even afterward, the parents took no apparent notice of my handling them in plain sight within 1 or 2 m. But after chicks were feathered, and particularly as the time of fledging approached, the confined parents became highly agitated as they were handled within view; they typically clambered about excitedly on the nearest face of the enclosure, all the while chattering and shrieking loudly and harshly. If the chicks flapped their wings or merely raised them on high, parental excitement reached a high pitch.

'Rescuing' youngest chick. When a family was flighted, a youngest bird, not fully fledged, frequently might be left behind. However, its slightest distress, as signaled vocally or by wing flapping, brought all members of the family to the rescue, not just the parents. Even young that were fledged early and separately housed from the parents to spare them from feather-picking, were followed, escorted, and protected on joint flightings. Such separately housed young also were tolerated as they climbed about outside their parents' enclosure, in circumstances in which other birds would have been attacked.

An analogy of Lovebird groups with chemical reagents. An analogy existed between my colony of lovebirds in their various groups in different enclosures, and chemical reagents on the shelf in the laboratory. Just as one could predict the chemical product to be expected from mixing any two given reagents, so also was I able to predict the type of interaction to be expected from flighting any two separately or jointly housed lovebirds. For example, I could predict the outcome of flighting a male with his mate, as opposed to the female whom he first sought to court, as opposed to his mate's sister, or his mother, or one of his older brothers, etc. (338, 339).

Lovebird and human mental processes. Guided by my studies of Peach-faced Lovebirds, concerning the existence of 'conscious awareness,' following the criterion of "versatile adaptability of behavior to changing circumstances and challenges" (after Dr. Donald Griffin), I see little room for doubt. But I would go further; I am hard put to find a substantial basis for concluding that Lovebird mental processes, as assessed from their social interactions, differ from those of mammals in any way but degree (346).

Cockatiels

Popularity second only to budgerigars. Like Budgerigars, Cockatiels (Nymphicus hollandicus or "goddess of Holland"), also called Quaarion and cockatoo parrots, are native to Australia. These handsome little parrots are second only to Budgerigars in popularity as cage and aviary birds, and, perhaps, in abundance in Australia as well. Inasmuch as Cockatielian behavior has been described extensively in the above treatments, my coverage of the birds here will be lesser.

Location of eggs. Eggs that are displaced to any position within a nestbox are recovered and returned to the site of laying and incubation by members of either sex  My attempts to relocate incubative areas within a nestbox was never tolerated; the eggs simply were returned to their original location. A male in breeding condition will incubate 'newly appearing' eggs placed at a former nest site, whether or not they were laid there (of which he had no knowledge), but a female generally will incubate eggs only if they are at the site of laying. She also may remove newly laid (but displaced) eggs from a former nest and restore them to the site where they were laid, even if her mate had accepted the new site and was incubating them, in which event she would 'steal' them from him in order to do so. A hen more than once moved an egg about 30 cm from a former nest to a location as near as possible to the position where she laid it.

Incubating divided clutches. The male and female will incubate a divided clutch independently, uncooperatively, and highly attentively, provided only that the female's portion (even only one egg) is at the laying site and the male's portion is in a former nest. In such a circumstance, the male abandons the eggs at night, whereas the female incubates by day and night, each bird following essentially the same pattern as during cooperative incubation of a single clutch. This behavior suggests that the warm-blooded, male ancestors of Cockatiels never incubated eggs at night (see 709 for further discussion).

One 'sure' way for the female to acquire the clutch. In my BBE paper on, "Presumptive Relict Reproductive....." I discussed the great competitiveness of the mates for the eggs. There was, however, one failsafe way for the female to acquire the clutch, no matter how otherwise uncooperative the male. To achieve this, the unsuccessful female would first leave the nestbox but turn around immediately and re-enter, 'diving in' under the male, from the inside perch, to the eggs, in one continuous motion. This maneuver invariable stimulated the male to rise and accommodate the female. It mattered not how adamant he might have been to retain the eggs a few seconds before, or might become a few seconds later. The male never employs this behavior.

Male 'encourages' female' to take 'desired' action. During a period when I was substituting colored marbles for eggs, both parents peered into the nestbox and eyed the colored marble warily from the outside perch; neither would enter. When the hen ventured halfway in, the male pecked her in the rump in an apparent effort to get her to enter all the way. Finally, she did enter. A male also sometimes would peck a female when both were away from the clutch, also in an apparent effort to get her to return to the nestbox. In the circumstances, there could have been no other interpretation of the pecks.

Care of hatchlings and nestlings. There are several misleading reasons why Cockatielian parents may appear to be ignoring a fresh hatchling (799, 800). Parental care and management of chicks, in some aspects of which the male participates more than the female, is a complex matter, discussed elsewhere (799-801). As the chicks near the time of fledging, the parents tenaciously guard the entrance of the nestbox and prevent the egress of the young-sometimes requiring vigorous physical measures. At the height of parental 'concern,.' when the young are learning to fly outside the enclosure, one or both parents always accompanies, escorts and, when necessary, seeks to rescue them.

The 'mandible fluttering' display. This is a rapid opening and closing of the bill that almost always occurs in parental interactions that concern the eggs and/or chicks within the nestbox (or within an incubative area on the enclosure floor). The male often mandible flutters while copulating, and the female usually does so immediately afterward. This display apparently has several functions, among them appeasement, expressing agitation or 'concern,' and as a recognition signal. In this connection, when the young of a previous brood of a breeding pair hear the singing and other sounds of coition of their parents, even out of sight of them, they are greatly stimulated. Typically, they set up a great din of whistling at such times.

Grooming the head. In this action to acquire an egg or the entire clutch (seemingly performed mostly by the male), the male grooms, without solicitation, every area of the female's head-incessantly and interminably (a tactic not previously known). As the grooming proceeds, the female's early receptivity turns to annoyance, thence to discomfort, then pain, and ultimately to 'desperation' for relief. At that point she counterattacks by pecking at the male, twists, turns away, shifts her position to avoid the male's attentions, rises for the same purpose, or flees the nestbox. In instances where the female merely shifts her position or raises her body, the male seizes on her moment of distraction to steal one or more eggs out from under her.

Feather-picking. Some parents picked feathers from the young for the purpose of consuming the nutritious, blood-saturated pulp at their bases, or in the case of very small emerging feathers, for consuming the entire feathers. Once acquired, the habit became fixed and pernicious, in which case the young had to be 'rescued' by one means or another.

Egg inspection. With the opportunity to observe birds in the nest or nestbox on an essentially continuous basis, aspects of egg attention by Cockatiels, both sexes of which incubate the eggs, became evident. Even the non-incubating bird visits the nest periodically and displaces the sitting bird long enough to make a thorough, close inspection of the eggs, particularly in later stages of incubation. The incubating bird also participates in all such inspections. As already noted, such displacements sometimes are achieved only after lengthy opposition by the sitting mate.

BUDGERIGARS

Budgerigars are the most widely known cage and exhibition birds in the world, and probably the most abundant of all Australian parrots. They are small, hardy, adaptable, streamlined birds, extremely easy to feed, house, and breed, and are among the most charming and attractive of all exotic birds. They become extremely tame with careful handling. As an aviary bird, they have no rival, and are by far the best exotic bird for the avicultural novice to keep. At no time in history has a pet so endeared itself or been in greater demand throughout the civilized world. Like Lovebirds and Cockatiels, they are strongly social (colonial) the year around in the wild, and normally aggregate into small parties or large flocks (40-43). Detailed treatments of all aspects of the biology of these birds are to be found in my book. The present treatment is confined to newly discovered aspects which, considering the popularity of the birds, can only be few in number.

Determnate versus indeterminate layers. The distinction between determinate and indeterminate layers is, as yet, poorly drawn, as comparisons between species have not been made with the same experimental regimes. The designation "determinate layers" has been applied to hens of a species that lay a certain number of eggs that does not become augmented when eggs are removed. In "indeterminate layers," the clutch size may show little variation when the eggs are left in the nest, but if eggs are removed, the number of eggs exceeds the normal clutch size. All three species of the present study were thought to be determinate layers. As is well known, most domesticated fowl are indeterminate, egg production having been increased by selective breeding. Insofar as breeding is concerned, budgies are obligatorily colonial.

Laying more eggs even as chicks hatch. An incredible circumstance, to my knowledge unprecedented ensued as I experimented with egg removal from a laying budgie. I left the first 2 or 3 eggs in the nest but removed each additional egg after laying. By the time the 13th egg was laid, the first 2 eggs had hatched. Of course, avian hens commonly incubate eggs while caring for chicks, but I know of no other instance of a hen continuing to lay eggs while caring for recently hatched chicks from the same clutch. This experiment illustrates the possibilities for variations in egg production and laying habits in response to experimental manipulations (or environmental variations) even in a species thought to be strictly determinate-laying.

Breeding in transparent nestboxes. There is no other record in the literature of budgies breeding in transparent nestboxes exposed to fluorescent light, as my pairs did. At first, the birds were adapted to the use of the nestbox, then each transparent sidepane was partially covered from the top with black cloth. But once oviposition began, the cloth gradually was raised to allow unobstructed view.

Searching for missing eggs. Experiments in which eggs were removed from incubating budgie hens established that finding a single missing egg of a clutch was enough to 'satisfy' a hen. Also, budgie hens do not routinely search the incubative area for possibly buried eggs. When they do search for missing eggs, the search does not extend much beyond the confines of the incubative area. Eggs beyond the confines are only recovered 'accidentally.'

Feeding of nestlings. Budgie parents were very selective in the feeding of seeds to young nestlings. They chose only round seeds and hulled oats, leaving spindle shaped canary seeds essentially untouched, though the latter were otherwise favored. Budgie nestlings differ from those of Cockatiels and Lovebirds. As they are fed, lying on their backs and their crops become full, they pull away and turn over on their bellies, even as hatchlings. Lovebird chicks are too uncoordinated for such movements, at any age. Cockatielian chicks almost always are fed in a sitting positions. They automatically droop lower and lower, as the weight of a filling crop pulls them down. By the time a crop is full, the chick no longer pumps or extends it head and neck upward to solicit.

I was able to confirm (findings in the literature) many times that the hen tends strongly to 'load up' the youngest chick first, before feeding older chicks. This ensures that the youngest chicks get the most liquid food, which becomes in short supply as the crop is emptied. Even as fledging time neared and the oldest chick solicited from the outside nestbox perch, Lucretia repeatedly reached past this chick to feed the youngest, who was soliciting from the inside perch of the nestbox. Sometimes Lucretia had to both force her way in and out as the oldest chick blocked the nestbox entry.

The male, on the other hand, tended to feed most frequently the most vigorously vocalizing young. Thus, once the male began to participate in feeding his nestlings, their solicitations began to increase within a day, showing that they were influenced by the fact that they were fed in response to vocalization. If both the hen and the nestlings were soliciting, the male fed the nestlings in preference to his mate.

Feeding of young chicks by older siblings. These acts were confirmed, and the tendency to do so is very strong. Feeding between chicks even occurred as I held them in my hand. 'Chain' feeding from parents to, and among, chicks was quite common. These strong feeding tendencies correlate with the equally strong tendency of the older chicks to perch in the nestbox entrance and on the inner and outer perches, often blocking the access and egress of the parents (neither Lovebird nor Cockatielian nestlings habitually engage in either act). Since the oldest nestlings are the first to perch in the entrance, they are likely to be fed there by the parents, as they block access. Since they usually are the ones who feed the other nestlings, it seems very likely that, in the wild, the behavior is a device for relaying food from the parents to the younger nestlings.

I have witnessed the origin of this behavior on several occasions. When a parent is feeding the young, the latter often are huddled together closely, proffering their bills for food. When the parent withdraws to regurgitate, in these circumstances, the young grasp each other's bills in the 'confusion.' And each seeks to obtain food from the other. These circumstances set the stage for subsequent unilateral and mutual feedings. See a discussion of this phenomenon (746,807,808). Feeding during the night also was confirmed.

Lack of nestbox sanitation. Unlike circumstances with Lovebirds and Cockatiels, there was no nestbox sanitation by either Budgie parents or young. Voiding was usually indiscriminate, and droppings were allowed to lie where they fell. As a result, the feet of the chicks were always caked heavily with dried excreta, despite my daily cleaning. Also, unlike Lovebirds and Cockatiels, Budgie parents showed no evident 'concern' for the safety of the young, as I handled and flighted them.

Feeding chicks and cleaning bills. I am unaware of any published details in this category. I quote from my book (784) on typical biparental feeding in this regard. Similar feeding behavior occurs in the other species. "Both parents allofed the chick competitively as it lay on its back [within 10-30 min after 'lights on' every morning], each 'impatiently' pushing the other's bill aside to take its own turn. In the brief intervals while one parent allofed before being displaced, the other cleaned excess food [including the recovery of pieces too large for the chick to swallow] from the bills of both its mate and the chick. Frequently Lysander's pushing aside of Lucretia's bill was followed by feeding Lucretia rather than the chick, usually with his head below hers as the food was transferred....Although Lysander usually cooperated with Lucretia in the feeding of a young chick, it was she who selected the chick that was to be allofed." Chicks also commonly were allofed by individual parents.

"Budgie milk." The gobs of glutinous (colostrum-like), semi liquid, creamy white food delivered to young budgie chicks differed in no discernible way from the food similarly delivered to young Lovebird and Cockatielian chicks. Accordingly, there would appear to be no reason to distinguish it therefrom by any such special designation.

Privacy preferred for sexual union. Numerous instances were observed in which Cockatiels and Lovebirds preferred privacy during copulation. An example with Budgerigars is most impressive. On one occasion a pair were in the act of copulation in an otherwise empty enclosure while the young were being flighted (796). "....one of the young alighted on the front face of the enclosure and began to sidle toward the entrance. To my astonishment, on perceiving the presence of the young bird, and without hesitation, Lysander dismounted, crossed to the entrance and expelled it from the vicinity. He then returned directly to Lucretia, remounted her, and resumed the sexual act. Subsequently, after completing coitus, he several times more expelled the young as they sought to re-enter the enclosure."

Lack of care of fledging and fledged young. The most striking departure in parental care by Budgerigars, as compared to the other two species, is its virtual total absence during and after fledging. This behavioral departure is perhaps the more impressive in view of the strongly selective feeding of the youngest chicks by the hen. This disregard for the welfare of fledglings strongly suggests that budgie nestlings in the wild do not leave the nest until they are entirely independent of parental care.

BIRDS IN GENERAL

Avian brains specialized for high speed decision making-no time for the luxury of inter-hemispheric cross-talk. To me, a most relevant message regarding the function of the avian central nervous system that is conveyed by the fact of a paucity of direct connections from the retinas to both hemispheres, and the findings concerning transfer of loss of fear and memories between the eyes, is the following. The avian brain has become specialized for high-speed responses at the expense of drawing upon its complete sensory input and/or complete store of sensory information (364).

Natural selection has led to something of a compromise in birds. Many of the pathways for extensive inter-hemispheric cross-talk in mammals have been lost in birds in the interests of high-speed decision making. In many of the situations that call for "split-second" decisions encountered by birds, there probably is no time for the luxury of extensive inter-hemispheric interrogation and integration. The tremendous capacities of mammals for storing, retrieving, and integrating the information that makes possible intelligent decisions confer no advantage to birds in critical, life threatening situations that require decision making at speeds too great to allow the use of these capacities. But even aside from the matter of rapidity of action, avian visual systems seem far superior to those of mammals, at least those of man. (364,365).

A broader perspective on instinctive responses by birds. A valid comparison of the powers of the brains of birds and mammals has to take into account more than just our interpretation of the appropriateness or adaptedness of birds' responses. It also has to allow for a crucial aspect that has played a much greater role for the bird than for the mammal-speed of decision making when millisecond decisions are critical in hunting, in escape, in avoidance, etc. This is a respect in which avian brains are far superior to those of mammals, with the possible exception of bats (367).

I would agree with Welty that "flight has proved to be an enormously successful evolutionary venture, but one that has cost birds dearly in mental development," but I view it from a somewhat different perspective. He sees flight as "a substitute for cleverness," in the view that birds solve many of their potential problems merely by flying away from them. I see the mental cost as the price that has had to be paid for the ability, itself, to exploit flight, that is, for the ability to make decisions at high speed. At the same time, I suggest that the cost has not been as great as usually is assessed. Thus, I emphasize the advantages of, rather than deprecate, highly stereotyped behavior, for which birds are known (368).

Pre-hatching vocalizations. It is said that precocial (sighted and able to walk at birth) and semi-precocial embryos begin to vocalize, with lung ventilation, 1-3 days before hatching, whereas altricial (blind and helpless at birth, 80% or more of all species) embryos do not vocalize (as opposed to bill clapping) until hatched. However, I often heard Cockatielian and Lovebird embryos vocalize within the shell many hours before hatching (191).

[It was not long after the appearance of my book that, on Aug. 10, 1988, J. C. McKee, Director of the Associateship and Fellowship Programs of the National Research Council invited me to agree to consideration as a future panelist for the NRC panel review process for NRC Research Associateship Programs, National Science Foundation Graduate Fellowship Program, Howard Hughes  Medical Institute Doctoral Fellowships in Biological Sciences Program, etc. At the time I was deeply involved in continuous 24-hr laboratory studies of learning and ambient light control by captive birds, that would not permit extended absences to visit Washington, D.C. for panel meetings, so I, of necessity, declined to be considered.]