Birds and all Nature, Vol. V, No. 2, February 1899
TextTHE HIBERNATION OF ANIMALS
NATURE presents no greater or more curious phenomenon than the habit of certain animals to conceal themselves and lie dormant, in a lethargic sleep, for weeks and months. It is known that in perfect hibernators the processes of nature are interrupted during the period of this long insensibility. Breathing is nearly, and in some animals, entirely suspended, and the temperature of the blood even in the warmer blooded animals, falls so low that how life can be maintained in them is a great mystery.
A variety of Rocky Mountain ground squirrels, when in perfect hibernation, says an observer, has a temperature only three degrees above freezing point of water, and when taken from their burrows are as rigid as if they were not only dead, but frozen. But a few minutes in a warm room will show that they are not only alive, but full of life.
As to the suspension of breathing in hibernators, the fact is proved sufficiently in the instances of the raccoon and the woodchuck. When they have laid themselves away for the winter sleep they roll themselves up comfortably and press their noses in such a position against their hinder parts that it would be an absolute impossibility for them to draw a breath. It is generally supposed that the bear rolls itself up in this way and does not breathe, but the holes melted in the snow beneath which the animal frequently stows itself, under a covering of leaves, prove that it does breathe while in its lethargy.
The marmot family produces the soundest winter sleepers. When the marmot is in its peculiar state of hibernation the electric spark will not rouse it. The most noxious gases do not affect it in the slightest. If its temperature is raised above that at which the animal breathed in its natural state it will die almost immediately.
Our own familiar wild animals, the bear, the raccoon, and the woodchuck – the so-called ground-hog – are classed as perfect hibernators, because they store no food for winter, but have acquired or provided themselves with a thick, fatty secretion between the skin and flesh, which, it is supposed, supplies them with sustenance. As a matter of fact, although dormant animals absorb fat, it does not enter into their digestive organs. Food introduced into the stomach of a hibernating animal, or reptile, by force or artificial means, will be found undigested at all stages of its lethargy, for it invariably goes into its peculiar state on an empty stomach. That is one of the mysteries of the phenomenon, not so great, however, as the fact that bears and woodchucks produce their young during their winter sleep. The male bear is frequently roused from his sleep and is found by the woodsman roaming about in mid-winter, but they have never known, they say, a female bear to be killed after the season for hibernation has set in.
Squirrels are only partial hibernators, from the fact that they work all summer and fall storing great quantities of food to supply them when hunger wakes them up during the winter, some of them, no doubt, spending very little time in a lethargic sleep.
The common land tortoise, no matter where it may be, and it is a voracious feeder, goes to sleep in November and does not wake up again till May, and that curious animal, the hedgehog, goes to sleep as soon as the weather gets cold and remains in unbroken slumber six months.
Bats, at the beginning of cold weather, begin to huddle together in bunches in hollow trees, dark corners in deserted houses, and in caves and crevices in the rocks. They gradually lose all sensibility, and continue in a comatose state until the return of genuine warm weather. When you see the first bat of the season fluttering at nightfall you can be sure that warm weather has come to stay. The little hooks at the end of one of the joints of each wing are what the bat hangs itself up by when it goes to sleep, whether for a day or for months. When the bats are clustering for hibernation one of the number hangs itself up by its hooks, head downward, and the others cling to it. It is on record that sixty bats have been found in one cluster, the entire weight of the lot being sustained by the one bat clinging with its hooks to whatever it had fastened them to at the start – a weight of at least ten pounds. The position of the central bat in such a cluster would be like that of a man hanging by his thumb-nails and supporting the weight of fifty-nine other men. So completely is animation suspended in the bat during the cold months that no test yet applied has induced it to show the least sign of life. Torpid bats have been inclosed by the hour in air-tight glass jars and not a particle of oxygen in the jars has been exhausted when they were taken out, showing that the bats had not breathed.
As cold drives certain animals, insects, and reptiles to a state of torpidity, so heat and lack of water bring about the same condition in others. The animal or reptile that hibernates, or goes to sleep in cold weather, arranges its body so that it will conduce to the greatest warmth, while those that estivate, or become torpid in warm weather, place themselves in positions that show that they want all the coolness the climate will permit. The tenric, a tropical animal, carnivorous and insectivorous, becomes torpid during the greatest heat, and lies on its back with its body drawn to its greatest length, and its limbs spread wide apart. Snakes estivate in the South, all kinds together, just as snakes hibernate in the North, but instead of rolling themselves in great balls, as the northern snakes do, they lie singly, and stretched to their full length.
Want of water will cause the common garden snail to go into a state of the most complete and curious lethargy. This is the snail of the genus Limax, not the larger one of the genus Helix. In the latter the phenomenon of hibernation is especially remarkable. In November the snail forms just a soft, silky membrane across the external opening of its shell. On the inner surface of that it deposits a coating of carbonate of lime, which immediately hardens the gypsum. This partition is again lined with a silky membrane. The snail then retires a little further into the shell and forms a second membranous partition, retiring again and again until there are six of these partitions between the snail and the lime-coated door at the entrance of the shell. In the recess behind all these partitions the snail lies torpid until May. All this time it lives without motion, without heat, without food, without air, without circulation or the exercise of any of its functions. If this snail is prevented from hibernating for several seasons by keeping it in a warm room, it will gradually waste away and die. A case is known where several snails of this genus were shut in a perforated box without food or water. They retired into their shells and closed them with a thin membrane. They remained so for three years, but revived when put into torpid water. They had been driven into torpidity by drought. The blood of this animal is white.
It may be of interest to state in connection with these animals who pass half the year, or less, in sleep, that there are several species of fish, reptiles, and insects which never sleep during their stay in this world. Among fish it is now positively known that pike, salmon, and gold-fish never sleep at all. Also that there are several others of the fish family that never sleep more than a few minutes during a month. There are dozens of species of flies which never indulge in slumber, and from three to five species of serpents which the naturalists have never been able to catch napping.
Apollo has peeped through the shutter,
And awakened the witty and fair;
The boarding-school belle's in a flutter,
The two-penny post's in despair.
The breath of the morning is flinging
A magic on blossom and spray,
And cockneys and sparrows are singing
In chorus on Valentine's day.
– Praed.
THE CAPE MAY WARBLER
(Dendroica tigrina.)
LYNDS JONES
THERE is hardly another group of birds that yields so satisfactory returns for earnest study as the American wood warblers. All shades and patterns of color are theirs, from somber to brilliant, from the plainest to the most intricate and exquisite pattern. Almost all degrees of vocal ability are found among them, from the simple twitter of the Tennessee to the wild thrilling challenge of the Louisiana water thrush or the ventriloquial antics of the yellow-breasted chat. Many bird students, it is true, regard the group as too difficult for any but the professional ornithologist to attempt; and that may be true of the females and of the autumnal plumages of the young, but the spring males are a constant inspiration and delight to one who admires variety in beauty.
It may be objected that the small size of the warblers renders their field study difficult, even if the foliage does not prove a serious hindrance. One must remember, however, that most small birds are not wary and that they may be closely approached, so that, with a good field-glass (and every bird-student should use one) their colors and the pattern of their dress can readily be made out even in the lower tree tops, where many of them feed. Foliage is always in the way, but even that can be circumvented by patience and perseverance.
The study of adult males in spring is greatly aided by the fact that each species, with some exceptions, has one or more patches of color peculiar to itself. Thus in the Cape May warbler the ear patches are rufous. Other species possess rufous colors, but none of them in this place.
The Cape May warbler belongs among the less common species, but may be common for a day or two during the height of the migration. It is very fond of orchards where it feeds among the foliage, snatching an insect here, a larva there, and cleaning the bundle of eggs from the leaf over yonder with an untiring energy. They also associate more or less with the other warblers in the woods. They are of great value to the fruit grower.
This species is found from the Atlantic coast west to the plains and north to Hudson's Bay, passing the winter in the tropics. It breeds from northern New England to Hudson's Bay and probably in northern Minnesota. The nest is built in a low bush in a wooded pasture or open woodland, said to be partially pensile. The nest and eggs are not readily distinguishable from those of several other warblers. The males sing frequently from their perch on the topmost twig of a spruce tree, thus misleading one as to the whereabouts of the female and nest. The song resembles somewhat that of the black and white warbler, but is rather less wiry. It cannot be represented on paper.
The tongue of this bird is worthy of special notice. It is cleft at the tip, and is provided with somewhat of a fringe. This character is not peculiar to this species, but is found in some honey creepers and in at least one foreign family of birds, thus suggesting, at least, the relationship of the warblers as a group. It might be asked, what is the significance of this character as regards feeding-habits? Apparently nothing, since the feeding-habits and food do not differ from those of other warblers not having the cleft tongue as greatly as the tongues themselves differ in structure. It is apparently an aberrant character developed somewhat at random among groups nearly related, or perhaps a remnant of structure.
SNOWFLAKES
Falling all the night-time,
Falling all the day,
Silent into silence,
From the far-away;
Stilly host unnumbered,
All the night and day
Falling, falling, falling,
From the far-away, —
Never came like glory
To the fields and trees,
Never summer blossoms
Thick and white as these.
To the dear old places
Winging night and day,
Follow, follow, follow,
Fold them soft away;
Folding, folding, folding,
Fold the world away,
Souls of flowers drifting
Down the winter day.
– John Vance Cheney.
A TIMELY WARNING
WHILE a British brig was gliding smoothly along before a good breeze in the South Pacific, a flock of small birds about the size, shape, and color of paroquets settled down in the rigging and passed an hour or more resting. The second mate was so anxious to find out the species to which the visiting strangers belonged that he tried to entrap a specimen, but the birds were too shy to be thus caught and too spry to be seized by the quick hands of the sailors. At the end of about an hour the birds took the brig's course, and disappeared, but towards nightfall they came back and passed the night in the main-top. The next morning the birds flew off again, and when they returned at noon the sailors scattered some food about the decks. By this time the birds had become so tame that they hopped about the decks, picking up the crumbs. That afternoon an astonishing thing happened. The flock came flying swiftly toward the brig. Every bird seemed to be piping as if pursued by some little invisible enemy on wings, and they at once huddled down behind the deck-house. The superstitious sailors at once called the captain of the brig, who rubbed his eyes and looked at the barometer. A glance showed that something was wrong with the elements and the brig was put in shape to out-ride a storm. The storm came down about twenty minutes after the birds had reached the vessel. For a few minutes the sky was like the waterless bottom of a lake – a vast arch of yellowish mud – and torrents of rain fell. Why it did not blow very hard, no one knows; but on reaching port, two days later, the captain learned that a great tornado had swept across that part of the sea. The birds left the vessel on the morning after the storm and were not seen again.
A WINDOW STUDY
OLIVE THORNE MILLER
ONE of the best places to study birds is from behind the blinds of a conveniently-placed window, where one can see without being seen.
My window one July looked into the tops of tall spruce trees, relieved here and there by a pine, a birch, or a maple. This was the home of the most fascinating and the most bewildering of feathered tribes, the warblers, and a rugged old spruce tree was a favorite "Inn of Rest" for every bird in the vicinity.
In all the years that I have known birds I have carefully avoided becoming interested in warblers, so tiny, so restless, so addicted to the upper branches, so every way tantalizing to study. But here, without intention on my part, fate had opened my windows into their native haunts, even into the very tree-tops where they dwell. "He strives in vain who strives with fate." After one protest I succumbed to their charms.
My principal visitor was a beauty, like most of his distinguished family, having a bright yellow head, set off by a broad black band beginning at the throat and running far down the sides, and he bore the awkward name "black-throated green warbler."
A bewitching and famous singer is this atom in black and gold. And not only is his song the sweetest and most winning, but the most unique, and – what is not generally known – the most varied.
The song that has been oftenest noticed, and is considered characteristic of the species, is sometimes syllabled as "trees, trees, beautiful trees," sometimes as "hear me Saint Theresa." But in my intimate acquaintance with some of the family that July I noted down from my window alone eight distinctly different melodies. My special little neighbor, who spent hours every day in the old spruce, sang the regulation carol of his tribe, but he also indulged in at least one other totally unlike that. Those two I have heard and seen him sing, one directly after the other, but he may have had half a dozen arrangements of his sweet notes.
Sometimes the mate of my spruce-tree neighbor appeared on the tree, going over the branches in a businesslike way, and uttering a loud, sharp "chip."
One morning there suddenly broke out in the old spruce a great clatter of "tick-et! tick-et!" in the voice of a nestling. I snatched my glass and turned it at once upon a much-excited warbler, my black-throated green. He was hopping about in a way unusual even with him, and from every side came the thread-like cries, while the swaying of twigs pointed out a whole family of little folk, scrambling about in warbler fashion and calling like bigger bird babies for food. They were plainly just out of the nest, and then I studied my spruce-tree bird in a new role, the father of a family.
He was charming in that as in every other, and he was evidently a "good provider," for I often saw him after that day going about in great anxiety, looking here and there and everywhere, while a small green worm in the beak told plainly enough that he was seeking his wandering offspring.
During the remainder of the month I frequently saw, and more frequently heard, the little family as they followed their busy parents around on the neighboring trees.
One day I noted the singer flitting about the top of the spruce, singing most joyously, and almost as constantly as before the advent of the nestlings, while the mother was hurrying over the lower branches of the same tree, collecting food for one youngster. Suddenly the song ceased, and the tiny papa joined the family party below, and addressed himself with his usual energy to the business of filling that greedy mouth.
Over and under and around and through the branches he rushed, every few seconds returning to stuff a morsel into the always hungry mouth, till he actually reduced that infant to silence, and then he slipped away, returned to his tree top, and resumed his lovely "tee-tee-tweetum!"
Somewhat later I heard the baby black-throats at their practice, droll, quavering attempts to imitate the musical song of their father. They soon mastered the notes, but the spirit was as yet far beyond them.
This happy life went on before my window till, almost at the end of July, a heavy fog swept in one evening from the ocean, and when, the next day, a cool north wind blew it back whence it came, it seemed to take the whole tribe of warblers with it. August was now upon the threshold, and in the bird world at least