Popular Science Monthly/Volume 59/June 1901/The Wild Bird at Arm's Length: A New Method of Bird Study
|THE WILD BIRD AT ARM'S LENGTH: A NEW METHOD OF BIRD STUDY.|
By Professor FRANCIS H. HERRICK,
IN the study of wild birds the problem of approach has always been difficult to master. The land birds of every continent are, as a rule, shy and difficult to study with that minuteness of detail which alone can satisfy the naturalist and careful observer of their habits.
Birds have enemies to fear and shun, and their discrimination does not exclude their most ardent or curious admirers from their bitterest foes. With them the battle is not always to the strong. Timidity, agility, protective colors and the instinct of concealment are as important in the struggle for life as the bill-hook and mailed foot. We speak of wild birds or of wild animals generally in contrast to the comparatively few which are tame, and if the wilderness does not always howl, it is often because its inhabitants have found it better policy to remain silent.
Wildness is due to fear which may be inherited or acquired by experience with this wicked world. Tameness on the other hand comes only through the casting out of fear, and may be effected by the formation of new habits, which are either spontaneous or forced. In order to tame a wild animal we must therefore teach it new lessons, and in doing this it is a common practice to literally chain it to a fixed spot, where its conditions of life are uniform and under control, and where no other teachers are allowed to interfere. The moment, however, the wild bird is placed in a cage its behavior is no longer perfectly spontaneous or free, at least not until all fear has been subdued. What is needed, therefore, is an invisible chain to hold the animals to some fixed and chosen spot, which may be approached in disguise.
Fortunately for the student of birds all these conditions are fulfilled for a very important period—that of life at the nest. The nest with its young is the given fixed point, and parental instinct is the invisible chain.
The method of the study and photography of birds now to be described consists in first bringing the birds to you and then camping beside them. They can thus be watched and photographed at arm's length, or even as near as one would hold a book to read, and under the most perfect conditions of light and position, for hours or days at a time, while quite unconscious of being observed.
To be more explicit the method depends mainly upon two conditions: (1) The control of the nest or nesting site, and (2) the concealment of the observer.
If the nest like that of an Oriole, Robin, Flycatcher, Waxwing or Vireo is fastened to any leafy branch, the nesting bough or twig is cut off, carefully taken down, carried to a convenient spot where there is good light, and firmly fastened to stakes driven into the ground. The change is one of space relations which may change with every passing breeze, and though it may be of little significance to the birds it is of
the utmost importance to the observer, since the nest now is but four instead of forty or more feet from the ground, and the screen of foliage which hid it from view has been withdrawn.
For an observatory I have adopted a green tent which conceals the student with his camera. The tent is pitched beside the nest, and when in use is open only at one point, marked by a small square window in line with the photographic lens and the nest.
By taking such liberties with wild birds, one might suppose we should bring destruction upon their homes and all that they contain, but happily this is not the case. No harm need befall either old or young. The former nesting site is soon forgotten, and the new quickly adopted and defended with all the boldness and persistence of which the birds are capable.
This method of studying birds thus depends mainly upon the strength of the parental instincts, and upon the readiness with which a bird learns to adapt itself to new conditions. Upon more complete analysis we recognize the following psychological principles, of which the following are the most important: (a) The strength of an instinct increases through its exercise, and may be reinforced by habit; (b) An
instinctive impulse may be blocked or suppressed by any contrary impulse; (c) The instinct of fear is often quickly suppressed by repetition, or the formation of new habits. One might also add that: (d) New habits are readily formed and may replace the old ones; (e) Abstract ideas, if they form any part of the furniture of the average bird-mind, are extremely hazy and fleeting; (f) Still further we must recall the physiological fact that birds are guided in most of their operations by sight and hearing, not by scent. Their olfactory organ is very rudimentary at best, and avails them neither in finding food nor in avoiding enemies.
Let us see how these principles are applied to the problem of approaching wild birds in the way described. The parental instincts begin to control the life of the adult with the periodic revival of the reproductive functions, and may vary greatly in their scope and intensity. As a rule this instinct, reinforced by habit, gradually increases until the young are reared. It is, therefore, safest to change the nesting surroundings when the parental instincts are approaching their culmination.
The general feeling of fear is gradually or quickly suppressed
according to the value of the different factors in the equation, by the parental instinct, which impels a bird at all hazards to go to its young wherever placed.
After a bird once visits the nest in its new position it returns again and again, and in proportion as its visits to the old nesting place diminish and finally cease, its approaches to the new position become more frequent, until a new habit has been formed, or, if you will, until the old habit is reinstated.
When the birds approach the nest any strange object, like the stakes which support the bough or the tent which is pitched beside it, arouses their sense of fear and suspicion, and they may keep away for a time or advance with caution. If very shy, like most catbirds, they will sometimes skirmish about the tent for two hours or more before touching the nest. The ice is usually broken, however, in from twenty minutes to an hour, and I have known a chipping sparrow and red eyed vireo to feed their young in three minutes after the tent was in place.
At every approach the birds see the same objects which work them
no ill. The tent stands silent and motionless, but the young are close by, and fear of the new objects gradually wears away. Parental instinct, or in this case maternal love, for the instinct to cherish the young is usually stronger in the mother, wins the day. The mother bird comes to the nest and feeds her clamoring brood. The spell is broken; she comes again. The male also approaches, and their visits are thereafter repeated.
Possibly the fears of the old bird? are renewed at sight of the window, which is now open in the tent-front, and of the glass eye of the camera gleaming through it, but the lens is also silent and motionless, and soon becomes a familiar object to be finally disregarded. Again there is the fear which the sound of the shutter, a sharp metallic click, at first inspires, unless you are the fortunate possessor of an absolutely silent and rapid shutter. At its first report, when two feet away, many birds will jump as if shot, give an angry scream, and even fly at the tent as if to exorcise an evil spirit, while after a few hours they will only wince; finally they will not budge a feather at this or any
other often repeated sound, whether from shutter, steam whistle, locomotive or the human voice.
It is the young, the young, always the young in whom the interest of the old birds is centered, and about whom their lives revolve. They are the strong lure, the talisman, the magnet to which the parent is irresistibly drawn. The tree, the branch, the nest itself, what are these in comparison with the young for whom only they exist? This is true notwithstanding the fact that birds will sometimes leave their young to perish while they start on their migrations. As a rule they follow one line of conduct until their instinct in this direction has been satisfied.
With some species it is possible to make the necessary change without evil consequences when there are eggs in the nest: with others we must wait until the young are from four to nine days old. It is all a question of the strength of the parental instinct, and this varies between wide limits in different species, and very considerably between different individuals. From the nature of the case there can be no infallible rule. If we know little of the habits of the bird in question, it is safest to wait until the seventh to the ninth day after hatching, or when, as in many of the common passerine birds, the feather-shafts of the wing-quills begin to appear, or, better, when they project from one-quarter to one-half inch beyond the feather-tubes. At this period the parental instinct is reaching its maximum, and, what is equally important, the sense of fear has not appeared in the young.
Young birds from one to five days old as a rule cannot stand excessive heat. Even when fed and brooded they will sometimes succumb, and here lies the serious danger to be guarded against. A nest of very young birds well shaded by foliage cannot be safely carried into the direct sunshine of a hot summer's day, hence the importance of beginning operations at the proper time when the weather is suitable, and further of not allowing your enthusiasm to get the better of your judgment.
The young may be handled or fed as much as one wishes, provided they have not acquired the instinct of fear. If you are uncertain as to this, and your aim is to study the nesting habits, it is better to avoid approaching, touching or in any way disturbing the young after the flight-feathers have appeared. The cutting of leaves or twigs which obstruct the light or cast undesirable shadows should be done before this time.
Young birds eight or nine days old stand the heat well, provided they are fed, but on very hot days they should not be allowed to go without food for more than two hours at the longest. Should the parents bring no food during this time, it is better to feed the young in the nest, and to suspend operations until the next day.
The old birds may be expected to come to the nest in from twenty minutes to an hour, when the tent is brought into use immediately after the removal of the nesting bough. It is naturally impossible to predict exactly what will happen until the experiment is tried, since the personal equation or individuality of the birds themselves is an unknown factor. One thing only is certain: that the parental instinct, reinforced by habit, will win in the end, that it will cast out fear and draw the birds to their young.
I have no desire to anticipate every objection which might be raised against the method, were it possible to do so, but after testing it to the best of my ability with the opportunities of two summers, I am confident of its value and am ready to stand sponsor for it in judicious hands. It is hardly necessary to insist that it is not designed for exhibition purposes, and that its successful practice requires some knowledge, with more patience and time.
An apparently serious objection is likely to occur to the ornithologist, namely, the liability of exposing the birds to new enemies. I feared lest prowling cats should discover the young whose nest and branch had been brought down from the tree-top and set up again in plain sight within easy reach from the ground, but I was happily mistaken. Predacious animals of all kinds seem to avoid such nests, as if they were new devices to entrap or slay them.
As for the weather, barring heat, which must be guarded against in the way described, the nesting bough is more secure when fixed firmly to supports than it could possibly have been before.
The tent not only conceals the observer, but protects his camera, an important consideration, since the prolonged action of the sun is liable to spring a leak in the bellows.
With note-book in hand you can sit in your tent and see and record everything which transpires at the nest, the mode of approach, the kind of food brought, the varied activities of the old and young, the visits of intruders, their combats with the owners of the nest, the capture of prey which sometimes goes on under your eye. No better position could be chosen for hearing the songs, responsive calls and alarm notes of the birds. You can thus gather materials for an exact and minute history of life at the nest, and of the behavior of birds during this important period. More than this, you can photograph the birds at will, under the most perfect conditions, recording what no naturalist has ever seen, and what no artist could ever hope to portray. The birds come and go close to your eye, but unconscious of being observed.
I have watched the night hawk feed her chick with fireflies when barely fifteen inches from my hand, the kingfisher carrying live fish to its brood whose muffled rattles issued from their subterranean gallery a few feet away. When near enough to count her respirations accurately, I have seen the redwing blackbird leave her nest on a hot day, hop down to the cool water of the swamp, and after taking a sip, bathe in full view, within reach of the hand; then, shaking the water from her plumage, she would return refreshed to her nest. I have seen the male kingbird come to his nesting bough with feathers drenched from his mid-day bath in the river, the orioles flash their brilliant colors all day long before the eye, and chestnut-sided warblers become so tame after several days that the female would allow you to approach and stroke her back with the hand.
It is difficult to describe the fascination which this method of study affords the student of animal life. New discoveries, or unexpected sights wait on the minutes, for while there is a well-ordered routine in the actions of many birds, the most charming pictures occur at odd moments, and there is an endless variety of detail. It is like a succession of scenes in a drama, only this is real life, not an imitation, and there is no need of introducing tragedy.
- Messrs. G. P. Putnam's Sons will shortly publish a book by Professor Herrick, in which the original method described in this paper will be given in greater detail, and the interesting results obtained will be more fully set forth. The book will be entitled 'The Home-Life of Wild Birds: A New Method of Bird Study and Bird Photography,' and will contain upwards of 140 illustrations from nature.—Editor.