Bird behaviour psychical and physiological

Front matter

Book ' r ^

YOUNG OF BARN-OWL.

AlthoughVtheir white down is very different from the feathers of the old birds these nestlings have the face just like the adult.

Chapter II

The locomotion of birds — ^Hopping and walking — Reasons for adoption of these gaits — Why waterfowl waddle — Swimming and diving — ^Perching and climbing — Different methods of performing these actions — Specialized birds which have taken to different habits, as Ground-Parrots and Land Geese — Flight and its varieties — Characteristic methods according to group and size — SaiUng and soaring flight — Speed . pp. 13-32

Chapter III

The nutrition of birds — ^Various kinds of food, animal and vegetable — ^Methods of and adaptations for obtaining it — Changes of diet — Gluttony of some species — Power of discrimination among foods, both vegetable and animal — ^The much-discussed relations of birds to insects, especially butterflies pp. 33-76 vi CONTENTS

Chapter IV

Nutrition {continued) — ^Manipulation of food — Powers of digestion, differing in different groups — ^The formation of pellets or castings — Difference in the food of old and young in some cases — Different methods of feeding the young — ^Young assisting parents in feeding their juniors — Feeding of each other by the sexes — Drinking, and eating of such substances as salt and earth ..... . . pp. 77-112

Chapter V

Propagation — Care of young — Different types of young birds — Different modes of feather-development, as seen in young Fovv^l, Pigeon, or Duck, for instance — Egg-coloration and its meaning and variations — Prolificacy and otherwise — Incubation mounds — Periods of incubation . . pp. 1 13-165

Chapter VI

Propagation {continued) — Nest-making not purely a bird-habit — Eggs laid without nests — ^Types of nests — Parasitic nesting — — Parasitic layers, like Cuckoos and Cow-birds — Degrees of development of parasitic instinct . . . pp. 166-205

Chapter VII

Migration — ^An anciently observed phenomenon still imperfectly understood — Reasons for it — ^Methods as far as is known — Difference between migratory species and the homing Pigeon — Widespread tendency to migration, contrasted with contradictory tendency to form localized non-migratory races, ending in some cases in Sightlessness, as in some birds of remote islands . » , , , t PP* 206-224

CONTENTS vii

Chapter VIII

The senses of birds — Sight and its general high development — Degree of perception of colour — Influence of colour, if any, on courtship, and the segregation of species — ^Perception of the' colour in various kinds of food — Smell, usually poorly developed — ^Exceptions noted — ^Acuteness of hearing — Sense of touch — ^Taste-perceptions . . . pp. 225-254

Chapter IX

The emotions of birds — ^Mentality higher than is supposed, but variable according to species or groups — Strong- and weakminded birds — Intelligence and stupidity — ^The limitations of instinct — ^Expression of the emotions and its relation to courting displays — Love and sociability — Hatred and revenge — ^The police instinct — ^Monogamy, polygamy, and polyandry — ^The problem of preferential mating pp. 255-280

Chapter X

Song and cries of birds — Bird-language generally — Extent to which the notes are instinctively developed — ^The instinct of mimicry — Species which can imitate human speech — ^Problem of this ability and extent of exercise of the same — ^Possibility of understanding of bird-language by man . pp. 281-292

Chapter XI

Weapons and fighting methods of birds— Their combats with each other and with various natural enemies — Chief enemies of birds — The passive resistance of birds to unfavourable climate and surroundings — Natural defences — ^Perfection and degeneracy of plumage in this connection — Powder-coating of some groups pp. 293-302 viu CONTENTS

Chapter XII

Special instincts of birds — ^The play of young birds and of adults — Bower-builders and their peculiarities — Ornamentation of nests — ^The instinct for food-storage in some forms — ^The practice of piracy — Toilet and bed- time habits pp. 303-318

Chapter XIII

Special physiological peculiarities of birds — ^Longevity — Temperature of body — Change of colour in bare skin of some, such as Turkey — ^The phenomena of the moult — Gradual change in colour of bill and feet according to age and sex or season — Changes in iris colour — Beak-sheath shedding as in Puffin

Chapter XIV

Abnormalities — Hybrids, their characteristics and power of reproduction or otherwise — ^Abnormal plumages, such as albinism or melanism, temporary or permanent — Overgrowth of claws and bill pp. 329-342

Chapter XV

Relations of birds with men — ^Persecuted species — ^Parasitic or commensal species — Domestic forms — Introduced forms and the results of introduction .... pp. S^SSS^^

ILLUSTRATIONS

Young of Barn-Owl .

Back of Frontispiece

Types of Pheasants .... Frontispiece

FAaNG PAGE

The Bird-Colony in the Calcutta Zoo . . lo

Nest of Sociable Weaver-Birds

II Puffin

. . 36

Great Black Woodpecker

. . 36

Merganser

. 36

Shoveller .

. . 36

Flamingoes

• 37

AVOCET

. . 46

HuiA (Female) .

. 46

HuiA (Male)

. . 46

Heron ....

. 46

Rhinoceros Hor^bill

• 47

Spoonbill .

• 47

Peregrine Falcon

• 47

Flamingo .

. 47

Rhinoceros Hornbills

. 50

Toco Toucans

• 51

IX

ILLUSTRATIONS

TO

Lyre-Birds (Male and Female)

Imperial Woodpeckers

BouRu Friar-Bird

BouRu Oriole, showing resemblance

Bird .....

Young Hoatzin ....

Brush-Turkey ....

OvEN-BiRD .....

Concave-Casqued Hornbill

Brazilian Hang-Nest

Types of Pensile Nests

Nest of Central-American Swift

GUACHAROS AND NeST

Flamingo on its Nest

SwiFTLETS AND THEIR NeSTS

Hawk-Cuckoo • OR "Brain-Fever Bird

Shikra Hawk

American King-Bird

King-Crow

African Jacana .

Cuban Trogon .

Gardener Bower-Bird with its Bower

Newton's Bower-Bird

Hybrid between Golden Pheasant and Fowl

Herring Gulls .

Frla.r-

FAONG PAGE

Chapter I

Importance of subject — Incompleteness of our information about even the commonest species — Distinction between major and minor habits — General activities or tricks of manner — Greater importance of the latter in classification — Errors to be avoided in observation.

The Study of birds is often looked down upon by general zoologists as a trifling pursuit, and the reason of this is not far to seek ; what is called zoology nowadays is for the most part the study of comparative anatomy, and from this point of view birds are of extremely small interest ; they are remarkably uniform in their general structure, and such variations of note as do occur are chiefly confined to a few flightless families, such as Ostriches and Pen^ guins.

One need not, indeed, be an anatomist to realize the comparatively small structural interest of birds ; a bird is at once and by everybody recognized as such, while among the mammals, their rivals in high development, one gets such extraordinarily different types as whales, mice, bats, horses, lions, I and men, most of whicli differ from each other more than the earliest known bird, the Archceofteryx of Jurassic times, does from the modern Sparrow in the back-garden.

On the other hand, the numerous species and families of birds and their close alliance with each other afford, by this very narrow range of differentiation, an attractive and philosophical study ; among them survive types which in mammals have become " missing links " or are only discoverable in the fossil state. In fact, it is the survival of so many connecting forms that makes it so difficult to group the families of birds into larger " orders," a difficulty which only occurs with mammals when we look back among their fossil predecessors preserved among the rocks.

We look, for instance, with interest upon the remains of the various ancestral predecessors of the horse family, as exhibited in museums, and try to realize what changes of habit must have occurred to convert a small animal with paws into a large one with a single hoofed toe on each foot. But among the birds, if we go to the Duck family {Anatida) we find still in existence practically all the links between a light-bodied, large-v^dnged bird with non-waterproof plumage and half-webbed feet with large grasping hind-toe, and almost exclusively aquatic diving Ducks which rival the Grebes and Cormorants in their subaqueous performances, and exhibit almost as much modification of structure. And the habits of these can be

DUCKS AND EVOLUTION 3

studied, for they are not only living, but accessible ; the semi- wader at the beginning of the series, the Australian Magpie-Goose {Anseranas semifalmatd) is no rarity, and I have spent much time in studying a fuU-wringed specimen at Kew, v^rhile the habits of many others of the family exemplifying the gradations I have mentioned are accessible either to direct observation or to any one who can look up bird literature.

In fact, the Duck family is one of the most interesting of all animal groups for any one interested in biological problems, ovdng to the wide distribution of its members, their essential and obvious alliance combined with equally striking differences — some obviously adaptive, others more inexplicable — and I shall have a good deal to say about them in the course of this book, especially as they are familiar exhibits in many public parks, and thus available for everybody's observation.

The availability of birds, as a class, for study gives them, in fact, an importance in the study of animal habits which fairly outweighs their insignificance from the morphological point of view ; and I personally have never admitted that the study of structure is more important than that of habit, considering that it only acquires its pre-eminence from the fact of demanding a professional training which is the prerogative of a few only. When one comes to think of it, we ourselves only surpass the other mammals in virtue of our habits, being structurally simply monkeys on our hind legs ; yet he would be a bold zoologist who would claim that comparative anatomy is a more important study than that of the manifold activities of mankind. If one admits that the study of habit is to be taken seriously — and of late there has been a decided trend in that direction — bird-watching needs no apology, for the habits of birds are of manifold variety, and not by any means fully understood, even in the case of the commonest and most familiar Species. In fact, these are sometimes, perhaps, less well understood than the comparatively inaccessible ones ; it has often struck me, in view of the excellent observations that have been made of late years in the Antarctic by various expeditions, that we know more about the mind and life of the Adelie Penguin, one of the remotest birds on the globe, than we do about those of the Peacock, the best known by sight and reputation of all birds for a couple of thousand years.

And here one must bear in mind that an observer should be no respecter of persons ornithologically ; a bird is not necessarily more worth observing because it is difficult of access, and that naturalist was very unscientific who said about the Sparrow, " I have got into the habit of not noticing this bird." Personally I am always seeing something fresh in the humble Sparrow's performances, and though my taste as a fancier lies in the direction of birds of beauty, I must admit that the humbler species are often more interesting. But they are not necessarily so ; dowdiness is no more a sign of

FREE AND CAPTIVE BIRDS 5

intellect in a bird than in a human being, and Aristotle was quite right in stigmatizing some birds as " dull in colour and leading a dull life," while some of those which are stigmatized as " garish " possess habits and qualities of surpassing interest, the Peacock in particular. I particularly mention the Peacock, because it is a purely Indian bird, but widely diffused about the world in a domestic state ; but its domestication is not rigorous, so to speak, and it is allowed to lead practically a natural life. This needs to be noticed, because there is a regrettable tendency among naturalists to confine their observations to the wild birds native to their own country, to the neglect of introduced, domesticated, and captive species.

A free bird is, of course, other things equal, the best and most instructive subject for observation, and many habits can only be observed on birds in a state of liberty, and in their own country at that ; but nevertheless, many very interesting hints may be gleaned from the study of birds not so situated, and these may always be checked by the study of their recorded habits in a natural state. Where such records do not exist, the study of captive birds is a useful stimulus to field observers to take up the matter, and often an observation on a tame or captive bird brings out a point which the field observer almost necessarily overlooks, owing, in many cases, to want of opportunity to discriminate between individuals — a point which will become evident later on.

The best of all birds for observation are, of course, those which live in a tame but free state in their ov^n country, such as Wood-Pigeons in London, and House-Crov7s {Corvus splendens) in Indian towns, though even here the difficulty of identifying individuals is a drawback. The growing practice of ringing birds, however, which is proving so useful in throwing light on problems of migration, will probably be of service in making records of individual birds in the near future, and in this connection it is worth noting that spring net-traps can be obtained in which many species of birds can be readily captured without injury for this purpose.

In considering the habits of birds we have to realize that they fall into two categories, which may perhaps be called major and minor habits, or perhaps, habits and. customs. By major habits I mean the leading and conspicuous life- activities of a species ; its food, manner of nesting, mode of association (solitary or gregarious), etc. On these its life obviously depends, and to them its structure is often plainly adapted. Yet, as its life depends on the adjustment of its main activities to its surroundings, it is just these habits that are particularly liable to vary even in a state of nature, and especially so under the influence of man's interference, direct or otherwise. Habits of this sort are fairly, though not completely known in the case of a vast number of birds, but will always require study, as they are so subject to modification by circumstances.

The minor habits, or mannerisms as we should

VERSATILITY OF SPARROW 7

call them in the case of persons, are not nearly so familiar, and have not been worked out fully even in many very well-known birds. Suqh are peculiarities in gait, flight, and other actions ; attitudes under emotion, positions assumed in repose, etc. Often these have no apparent connection with any necessity, and they are practically invariable for the species and often for the group, and not alterable by circumstances.

To take a concrete instance ; the common Sparrow, as every one knows, eats seed, for the cracking of which its bill is specially adapted ; it perches in trees, and has feet adapted for grasping twigs ; it also builds its nest in trees, and associates in pairs and flocks. These are its major habits, and every one knows they are subject to modification ; it eats many things besides seed, especially remnants of man's food ; it builds under eaves as well as among boughs, and will sleep in its nest or in a crevice of a wall, as well as on a twig, in spite of its grasping feet. In spite of its short wings, it chases insects in the air, and hovers and drops on them in long grass like a miniature Kestrel.

In other words, its major activities are, though to some extent correlated with its structure, highly variable, and this, no doubt, is one great reason for its success as a species. If actively interfered with by man it can vary still more ; a hand-reared Sparrow has been known to acquire a Linnet's or Canary's song.

In some points, however, the Sparrow is invariable ; it never acquires tlie habit of holding down its food with one foot, though this would be of vital importance to it in enabling it to consume large articles of food when perched on a small bough, and thus escape risk of ground enemies. Though largely a ground-feeder, it hops and does not run, and does not hold up its tail to keep it clear of wet ; when courting it has a definite display, with wings lowered and head and tail raised. It rolls in dust as well as washing, a combination of habits rare among birds, and when scratching itself it lowers its wing and raises its foot over it. Some of these minor habits may have significance, but this is not obvious ; what is obvious is that they are common to all Sparrows, and are often group-characters ; thus, all the vast group of generally small birds — the Passerines, of which the Sparrow (Passer) is type and name-father — seem to drop a wing when scratching. Habits of this kind do not alter even in captive birds, although they may learn strange habits of feeding and nesting, and even alien songs.

Hence such characters are often useful in classification, just as anatomical characters or inconspicuous external ones are of more importance than the general contour. Thus, all anatomists of late years have impressed upon us that the Swallows and Swifts must not be considered near relatives because of their similar forms — long-winged, smallfooted, and short-billed — since these may be accounted for by adaptation to a similar life spent in

SWIFTS AND SWALLOWS 9

chasing flying insects, and the anatomical characters of the Swifts differ from those of the Swallows, which present no important internal differences from the ordinary small passerine birds. There are small differences also in external characters which are not to be correlated with modes of living ; the Swifts have but ten tail-feathers to the Swallows' twelve, and have not the scales on their shanks which are usual in birds. There is also a conspicuous difference in habit which seems to have no relation to utility, and hence is more likely to be a family character ; in flight the Swallow every now and then draws in its wings to its sides — it still shows a sign of the typical small passerine bird's flight with its occasional dips with closed wings — while the Swift always keeps its wings fully expanded, whether skimming motionless or renewing its impetus by means of wing-beats.

Small details of habit are thus always worth observing, as they may be more significant than they seem, and in any case are good practice in observation.

Some pitfalls in observation or in drawing conclusions from the same need mentioning in conclusion. The danger of the major habits becoming modified in captivity or domestication has been alluded to, and is, indeed, made rather too much of by some writers ; still, it is well to bear it in mind. There is also the difficulty of the field observer in discriminating between individuals — often between the sexes, when these are alike. One must never assume anything ; if a bird is displaying, it is not necessarily a male, for instance. Quite apart from the fact that in many species the hen is the dominant sex, as in Phalaropes and Cassowaries, the hen may display even in those in which the male is well differentiated and very self-assertive ; thus, I have seen a Peahen display to a Peacock, and a hen Turkey to the gobbler, these males in both cases remaining passive, so that had the sexes been alike, one would certainly have been tempted to draw very false conclusions about their behaviour.

Then one must be very cautious in keeping free from prepossessions ; it is quite easy to see what is not there, if one has some image already in one's mind. We laugh at the error of the old naturalists who credited the Osprey, as a fishingbird-of-prey, with one taloned foot and one webbed one ; these odd extremities no doubt seemed to them appropriate, but I have seen almost equally gross instances of faulty observation of points of form and colour in the work of modern naturalists of the best repute.

Such errors can, of course, easily be checked, but when it comes to actions, unless the camera is at hand for the recording of such (which can be but rarely the case), the evidence is necessarily dependent on a number of witnesses. Every one is liable to err, and any observer is liable to have the opportunity of observing an action or occurrence which is rare or strange, and will be disbelieved until some one else arises to confirm it.

liMfe

NEST OF SOCIABLE WEAVER-BIRDS.

Republican Grosbeak " was the old name for this Weaver, which is a plain-plumaged. Sparrow-like bird.

^mitJiUi^^^

INCONSISTENT CORMORANTS ii

One should thus be very careful in discrediting the observations of others if they do not happen to agree with one's own, especially if such were recorded many years ago ; a record is not necessarily bad because it is ancient, nor good because it is new. Even one's own observations may contradict each other at times, as happened to me in my experience of our wild colony of the small Indian Cormorant {Phalacrocorax javanicus) in the Calcutta Zoo. These birds came in the evenings to their roosting-place on a wooded island in a large pond, and usually swooped down, Swallow-fashion, to take a drink on the wing before going up to roost. This was an unusual feat for a Cormorant to perform (although it must be remembered that this species is a light-built, long-tailed bird of only the size of a Teal), and, from the way in which the birds began to gape before touching the water, and often involuntarily checked their way so much that they had to settle after all, they evidently found it a difficult one. It so happened, too, that once for some time they gave the habit up, and settled in flocks in the water to drink in the normal way, though they afterwards resumed the custom of the flying sip ; and I can well imagine that any one who had seen them thus drink sitting would put down my record of the flying drink as most far-fetched and out of all congruity with the structure and habits of a Cormorant.

Very likely the birds had adopted a really new habit, in drinking flying ; at any rate, we know new habits do occur — I rather fancy that I dropped across one of late, in finding the Sparrows peeling off the inner bark of the limes for nesting-material, even when they could easily get straw, and I find the habit not uncommon in the Regent's Park district, as many barked branches testify.

There is, therefore, always room for observation, confirmatory or original, and no conscientious observer need fear to record what he or she sees, for there is no such thing as authority in science, and the veriest beginner may often put the expert to the blush.

Chapter II

The locomotion of birds — Hopping and walking — Reasons for adoption of these gaits — Why Waterfowl waddle — Swimming and diving — Perching and climbing — ^Different methods of performing these actions — Specialized birds which have taken to different habits, as Ground-Parrots and Land-Geese — Flight and its varieties — Characteristic methods according to group and size — Sailing and soaring flight — Speed.

So old an author as Pliny gives some remarks on the locomotion of birds, many of them quite accurate, as when he points out that Crows walk and Sparrows and Blackbirds hop. Such differences in action are well known to most people, but it is just as well to have them summarized.

The usual gait of birds is a walk, that is to say, when they are considered by groups ; it is true the majority of small birds one sees are hoppers, but that is because the common small birds of most parts of the world are passerines, and in this group hopping is the usual gait, walking being customary only in some of the larger species, such as Crows, and in groups which, like Crows, habitually seek food or even live on the ground, such as Wagtails,

X3

Pipits, Larks, and Starlings. As passerine birds are all primarily adapted for a life in trees, even the Larks still having a typical percher's foot, and as jumping from bough to bough is a natural and habitual movement, it seems natural that this should be continued in all except those most thoroughly adapted to a ground life.

The same reasoning applies to the Hornbills, among v^hich family are to be found the only large birds which hop ; there are two species of this usually very short-legged and highly arboreal family which have legs of the ordinary length and live mostly on the ground, the Ground-Hornbills {Bucorax)y and these move their legs alternately in the ordinary walking fashion and are even able to run well, which some walking birds do not do — most Herons and Storks, for instance. In the case of these Hornbills, it is to be noted that the hind toe is just as well developed as in the perching kinds, and that they walk on the end joints of the toes, the ball of the foot being raised above the ground, so that one could put a marble under it. This would be unique among birds, which usually tread on the whole under-surf ace of the toes, where these are on the same level — i,e, the hind toe not set on higher — ^were it not for the case of the Ostrich, which lifts the basal joints of its two toes off the ground even more, so that its foot can fairly be said to have a pas tern- joint, like that of the hoofed beasts with which it habitually grazes. In the Ostrich reduction of the toes is carried to an

HOPPERS AND WALKERS 15

extreme, but in most running birds the hind toe is absent or greatly reduced, and useless, so that the case of the Ground-Hornbills, Larks, Desert- Choughs (Podoces)^ and other running members of perching groups is unique, as they alone of all running creatures have the bearing- surface of the foot well developed behind as well as in front.

Unfortunately for our explanation, the Hornbills and passerines do not exhaust the list of groups of birds in which some members run and others hop ; and in the other cases it is difficult to assign a reason for the difference of gait. Pigeons, except some (not all) of the most terrestrial kinds, are all short-legged, and most live largely in trees, but they nearly all walk, although some of the most arboreal Fruit-Pigeons do hop as well ; I have seen this most in the Lilac-crowned Fruit-Pigeon {Ptilofus coronulatus). Parrots, again, are mostly tree-birds, and all short-legged, some very much so, but they generally walk, although the Lories form an exception by hopping. Kingfishers do not move on their feet at all if they can help it, and all without exception are very short on the leg ; yet the great Australian Laughing Jackass, which is more of a ground-feeder than any other, is a hopper, while the few others I have been able to study all walk, or rather waddle. So do Bee-eaters, at least the Australian and European species (Merops ornatus and M. apiaster) ; but of two Indian kinds of Nightjars I have seen one walk and the other hop, and the only Trogon {Prionotelus temnurus) whose gait I have ever studied, hopped; and all these birds are short-legged. The shortest-legged Passerines, too, are the Swallows, but these walk when on the ground instead of hopping. Among Cuckoos and Rollers, the practice is more rational, so to speak, for the short- legged species hop, while the longerlegged Ground- Rollers and the magpie-like Bush- Cuckoos, Hke the Indian Crow-Pheasant (Centropus sinensis), run. Toucans, Barbets, and Woodpeckers all seem to hop, and this about exhausts the list of hopping birds, all of which, it will be noticed, are essentially perchers, so that hopping undoubtedly has something to do with the perching habit.

Walking-birds, however, may hop when in a hurry, as one may see with Rooks, Starlings, and even Wood-Pigeons, while birds of prey, which normally walk, though but little, hop so readily when *' cornered" by a broken wing as to have given rise to the notion that hopping is their natural gait. Conversely hopping birds of the Thrush tribe often take a run for a few feet. Waterfowl have a bad name for clumsiness in walking, and certainly some of the more specialized kinds waddle awkwardly on account of the wide distance between their legs, which is convenient for swimming, but necessarily produces a rolling gait. This also badly handicaps them in perching, which so many of them do, especially in hot climates, for they find it difficult to walk along a small bough ; and in the case of the perching Ducks, the dwarfed hind- toe is of no use for a grip, so much so that I have seen such active species as

PERCHERS AND CLIMBERS 17

the Mandarin Duck and Andaman Teal {Nettium albigulare) slide right over and off a perch on which they had tried to alight. Only Cormorants and Darters among waterfowl seem at all at home in trees, and these have a powerful gripping foot with well-developed hind-toe, and more freedom in the legs than is usual in diving birds.