The Woodpeckers

VIII

EL CARPINTERO

In California and along the southwestern boundary of the United States lives a woodpecker known among the Mexicans as El Carpintero, the Carpenter.

Carpentering is both his profession and his pastime, and he seems really to enjoy the work. When there is nothing more pressing to be done, he spends his time tinkering around, fitting acorns into holes in such great numbers and in so workmanlike a fashion that we do not know which is more remarkable, his patience or his skill. Every acorn is fitted into a separate hole made purposely for it, every one is placed butt end out and is driven in flush with the surface, so that a much frequented tree often appears as if studded with ornamental nails. “What an industrious bird!” we exclaim; but still it takes some time to appreciate how enormous is the labor of the Carpenter. Whole trees will sometimes be covered with his work, until a single tree has thousands of acorns bedded into its bark so neatly and tightly that no other creature can remove them.

We may take for examination, from specimens of the Carpenter’s work, a piece of spruce bark seven inches long by six wide, containing ten acorns and two empty holes. As spruce bark is so much harder and rougher than the pine bark in which he usually stores his nuts,2 this specimen looks rough and unfinished, and even shows some acorns driven in sidewise; but for another reason I have preferred it to better-looking examples of his work for study. As we shall see later, it gives us a definite bit of information about the bird.

Think of the work of digging these twelve holes. Think of the labor of carrying these ten large acorns and driving them in so tightly that after years of shrinking they cannot be removed by a knife without injuring either the acorn or the bark. Yet how small a part of the woodpecker’s year’s work is here! How long could he live on ten acorns? How many must he gather for his winter’s needs? How many must he lose by forgetting to come back to them? We cannot calculate the work a single bird does nor the nuts he eats, for several birds usually work in company and may use the same tree; but all the woodpeckers are large eaters, and the Californian has been singled out for special mention.

Can we estimate the amount of work required to lay up one day’s food? Judging by the amount of nuts some other birds will eat, I should think that all ten acorns contained in this piece of bark could be eaten in one day without surfeit. The estimate seems to me well inside of his probable appetite. I have experimented on this piece of bark, using a woodpecker’s bill for a tool, and it takes me twenty minutes to dig a hole as large but not as neat as these. Doubtless it would not take the woodpecker as long; but at my rate of working, four hours were spent in digging these twelve holes. Then each acorn had to be hunted up and brought to the hole prepared for it. This entailed a journey, it may have been only from one tree to another, or it may have been, and very likely was, a considerable flight. For these acorns grew on oak-trees, and we find them driven into the bark of pines and spruces.

This it is which gives our specimen its particular interest. While oaks and pines may be intermingled, though they naturally prefer different soils and situations, and in the Rocky Mountains the pine-belt lies above the oak region, spruce and oak trees do not grow in the same soil. The spruce-belt stands higher up than the pine. As these nuts are stored in the bark of a spruce-tree, we have clear evidence that the bird must have carried them some distance. For every nut he made the whole journey back and forth, since he could carry but one at a time, – ten long trips back and forth, certainly consuming several minutes each.

Then each acorn had to be fitted to its hole. We have already spoken of the accuracy with which this is done, so that the Carpenter’s work is a standing taunt to the hungry jays and squirrels which would gladly eat his nuts if they could get them. A careful observer tells us that when the hole is too small, the woodpecker takes the acorn out and makes the hole a little larger, working so cautiously, however, that he sometimes makes several trials before the acorn can be fitted and driven in flush with the bark. Some of these acorns show cracks down the sides, as if they had been split either in forcibly pulling them out of a hole not deep enough for them, or in driving them when green and soft into a hole too small for them. Of course after each trial the acorn must be hunted up where it lies on the ground and driven in again, and this takes considerable time.

As nearly as we can estimate it, not less than half a day must have been spent in putting these acorns where we find them. With smaller acorns, stored in pine bark, less time would have been required; but weeks, if not months, of work are spent in laying up the winter’s stores.

How the woodpecker’s back and jaws must have ached! Surely he is human enough to get tired with his work, and it is not play to do what this bird has done. Some of the acorns measure seven tenths of an inch in diameter by nine tenths in length, and the bird that carried them is smaller than a robin. How he must have hurried to reach his tree when the acorn was extra large! Yet he took time to drive every one in point foremost. Even those that lie upon their sides must have been forced into position by tapping the butt. He knows very well which end of an acorn is which, does our Carpenter.

But what is the use of all this work? Why, if he wants acorns, does he not eat them as they lie scattered under the oaks, instead of taking pains to carry them away and put them into holes for the fun of eating them out of the holes afterward? The absurdity of this has led some people to surmise that the Carpenter chooses none but weevilly acorns, and stores them that the grub inside may grow large and fat and delicious. This would be very interesting, if it were true. There must of course be more weevilly acorns on the ground than he picks up, so that he could get as many grubs without taking all this trouble, and there is no reason why they should not be as large and good as those hatched out in holes in trees. When I wish to keep nuts sweet, I spread them out on the attic floor in the sun and air, keeping them where they will not touch each other. The Carpenter does practically the same thing. Is it probable that he tries to raise a fine crop of grubs in this way? If so, one or the other of us is doing just the wrong thing. But if weevils are what the Carpenter wants, then the nuts in the bark should be wormy; yet only two of them show any sign of a weevil, and of these one appears from its dull color and weather-beaten look to be a nut deposited several years before the others by some other woodpecker. Every other acorn is as hard, shining, and bright colored as when it fell from the tree. Evidently the bird picked these nuts up while they were fresh and good; perhaps he chose them because they were good and fresh. The possibility becomes almost a certainty when we observe that naturalists agree that the Carpenter uses no acorns but the sweet-tasting species. Now there are likely to be as many grubs in one kind of an acorn as in another, and he would scarcely refuse any kind that contained them, if grubs were what he wanted. The fact that he takes sweet acorns, and those only, shows that it is the meat of the nut that he wants. And all good naturalists agree that it is the kernel itself that he eats.

Why he stores them is not hard to decide when we remember that the Californian woodpecker, over a large part of his range, is a mountain bird. Though we think of California as the land of sunshine, it is not universal summer there. The mountain ranges have a winter as severe as that of New England, with a heavy snowfall. When the snow lies several feet deep among the pines and spruces of the uplands, the Carpenter is not distressed for food: his pantry is always above the level of the snow; he need neither scratch a meagre living from the edges of the snow-banks, nor go fasting. His fall’s work has provided him not only with the necessities, but with the luxuries of life.

But why does he spend so much time in making holes? He might tuck his nuts into some natural crevice in the oak bark, or drop them into cavities which all birds know so well where to find. And leave them where any pilfering jay would be able to pick them out at his ease? Or put them in the track of every wandering squirrel? Jays and squirrels are never too honest to refuse to steal, but they find it harder to get the woodpecker’s stores out of his pine-tree pantry than to pick up honest acorns of their own. So, like the woodpecker, they lay up their own stores of nuts, and feed on them in winter, or go hungry.

We have had very little aid from anything except the piece of bark we were studying, yet we have learned that the Californian woodpecker is a good carpenter; that he works hard at his trade; that he shows remarkable foresight in collecting his food, much ingenuity in housing it, good judgment in putting it where his enemies cannot get it, and wisdom in the plan he has adopted to give him a good supply of fresh nuts at a season when the autumn’s crop is buried under the deep snow.

If I were a Californian boy, I think I should spend my time in trying to find out more about this wise woodpecker, concerning which much remains to be discovered.

IX

A RED-HEADED COUSIN

Besides his half-brothers, the narrow-fronted and ant-eating woodpeckers, the Carpenter has a numerous family of cousins, – the red-headed, the red-bellied, the golden-fronted, the Gila,3 and the Lewis’s woodpeckers. These all belong to one genus, and are much alike in structure, though totally different in color. Most of them are Western or Southwestern birds, but one is found in nearly all parts of the United States lying between the Hudson River and the Rocky Mountains, and is the most abundant woodpecker of the middle West. This well-known cousin is the red-headed woodpecker, the tricolored beauty that sits on fence-posts and telegraph poles, and sallies out, a blaze of white, steel-blue, and scarlet, a gorgeous spectacle, whenever an insect flits by. He is the one that raps so merrily on your tin roofs when he feels musical.

In many ways the red-head, as he is familiarly called, is like his carpenter cousin. Both indulge in long-continued drumming; both catch flies expertly on the wing; and both have the curious habit of laying up stores of food for future use. The Californian woodpecker not only stores acorns, but insect food as well. But though the Carpenter’s habits have long been known, it is a comparatively short time since the red-head was first detected laying up winter supplies.

The first to report this habit of the red-head was a gentleman in South Dakota, who one spring noticed that they were eating young grasshoppers. At that season he supposed that all the insects of the year previous would be dead or torpid, and certainly full-grown, while those of the coming summer would be still in the egg. Where could the bird find half-grown grasshoppers? Being interested to explain this, he watched the red-heads until he saw that one went frequently to a post, and appeared to get something out of a crevice in its side. In that post he found nearly a hundred grasshoppers, still alive, but wedged in so tightly they could not escape. He also found other hiding-places all full of grasshoppers, and discovered that the woodpeckers lived upon these stores nearly all winter.

But it is not grasshoppers only that the red-head hoards, though he is very fond of them. In some parts of the country it is easier to find nuts than to find grasshoppers, and they are much less perishable food. The red-head is very fond of both acorns and beechnuts. Probably he eats chestnuts also. Who knows how many kinds of nuts the red-head eats? You might easily determine not only what he will eat, but what he prefers, if a red-headed woodpecker lives near you. Lay out different kinds of nuts on different days, putting them on a shed roof, or in some place where squirrels and blue jays would not be likely to dare to steal them, and see whether he takes all the kinds you offer. Then lay out mixed nuts and notice which ones he carries off first. If he takes all of one kind before he takes any of the others, we may be sure that he has discovered his favorite nut. Such little experiments furnish just the information which scientific men are glad to get.

It is well known that the red-head is very fond of beechnuts. Every other year we expect a full crop of nuts, and close observation shows that the red-heads come to the North in much larger numbers and stay much later on these years of plenty than on the years of scanty crops. Lately it has been discovered that they not only eat beechnuts all the fall, but store them up for winter use. This time the observation was made in Indiana. There, when the nuts were abundant, the red-heads were seen busily carrying them off. Their accumulations were found in all sorts of places: cavities in old tree-trunks contained nuts by the handful; knot-holes, cracks, crevices, seams in the barns were filled full of nuts. Nuts were tucked into the cracks in fence-posts; they were driven into railroad ties; they were pounded in between the shingles on the roofs; if a board was sprung out, the space behind it was filled with nuts, and bark or wood was often brought to cover over the gathered store. No doubt children often found these hiding-places and ate the nuts, thinking they were robbing some squirrel’s hoard.

In the South, where the beech-tree is replaced by the oak, the red-heads eat acorns. I should like to know whether they store acorns as they do beechnuts. Are chestnuts ever laid up for winter? How far south is the habit kept up? Is it observed beyond the limits of a regular and considerable snowfall? That is, do the birds lay up their nuts in order to keep them out of the snow, or for some other reason?

It remains to be discovered if other woodpeckers have hoarding-places. We know that the sapsucker eats beechnuts, and the downy and the hairy woodpeckers also; that the red-bellied woodpecker and the golden-winged flicker eat acorns; and I have seen the downy woodpecker eating chestnuts, or the grubs in them, hanging head downward at the very tip of the branches like a chickadee. It may be possible that some of these lay up winter stores.

It is known that the Lewis’s woodpecker occasionally shows signs of a hoarding instinct. It was recently noted that in the San Bernardino Mountains of California the Lewis’s woodpecker, after driving away the smaller Californian woodpeckers, tried to put acorns into the holes the Carpenter had made, but, being unused to the work, did it very clumsily. Soon after this observation was published, a boy friend living near Denver told me that a short time before he had seen a woodpecker that had a large quantity of acorns shelled and broken into quarters, on which he was feeding. This woodpecker was identified beyond a doubt as the Lewis’s woodpecker. So we begin to suspect that the habit of storing up food is not an uncommon one among the woodpeckers.

X

A STUDY OF ACQUIRED HABITS

Something interesting yet remains to be discovered of the hoarding habit of the red-head. How strange that so familiar a bird should have a habit so easily detected, and yet that no one in all these years should speak of it! Who does not know how mice and chipmunks hide their food? Who has not watched the blue jay skulking off to hide an acorn where he will be sure to forget it? Who does not remember the articles his pet Jim Crow stole and lost to him forever? The hoarding habit has long been observed of many dull-colored, rare, or insignificant creatures. That one so noisy, gay-colored, tame, and abundant as our red-headed woodpecker should have the same habit and escape observation is certainly remarkable. But though it is over twenty years since the storing of grasshoppers was recorded and twelve since the practice of laying up beechnuts was observed, very little seems to have been learned of the habit since these records were made.

There are two points to be considered: the habit long remained unknown; after it was discovered, it was long in being reaffirmed. It seems that, if it were a general habit, more would be known about it. Now if it is not a universal habit, it must be one of two alternatives, either a custom falling into disuse, or a new one just being acquired. That a habit so remarkable and so advantageous should be discarded after being universal is scarcely possible; that a habit so noticeable, if it were general, should remain unknown is improbable; that a habit which made life in winter both secure and easy should, if introduced by a few enterprising birds, become a universal custom, is not without a parallel. The probabilities point to the custom of hoarding food as a recently acquired habit.

Acquired habits are not rare among birds. The chimney swift has learned to nest in chimneys since the Pilgrims landed; for there were no chimneys before that time. There is the evidence of old writers to show that they acquired the habit within fifty years of the time of the first permanent settlements in New England. The eaves swallow learned to transfer its nest from the side of a cliff to the side of a barn in less time. Most birds will change their food as soon as a new dainty is procurable, and they will even invent methods of getting it, if it is much to their taste. The way the English sparrows have learned to tear open corn husks so as to eat the corn in the milk is a good example, for our maize does not grow in England, and they have had to learn about its good qualities in the few years since they have become established outside of the cities. Yet it is already a well-established habit. So quickly does a habit spread from one bird to another, until it becomes the rule instead of the exception! Acquired habits always show adaptability, and often much forethought and reason. It is the shrewd bird that learns new tricks.

Now there is not known among birds any evidence of greater forethought and reason than working hard in pleasant weather, when food is plentiful beyond all hope of ever exhausting it, to lay up provision for winter. How does the woodpecker know that winter will come this year? That there was a winter last year and the year before does not make it certain, but only probable, that there will be one this year. We cannot know ourselves that the seasons will change until we learn enough of astronomy to understand the proof. Nor does instinct explain the habit, as some would declare: since not all red-heads have the habit, though all must have instinct. It would seem as if memory and reason had devised this plan for outwitting winter, the bird’s old enemy.

The red-head is not a grub-eating woodpecker. Though beetles make up a third of his food, their larvæ do not form any part of it. Half his food for the entire year is vegetable, and the animal portion is composed principally of beetles, ants, caterpillars, and grasshoppers, which in winter time are hidden in snug places, or are dead under the snow. There are few berries in winter. The few seedy, weedy plants that stick up above the snow give to the birds the little they have; but the red-head’s vegetable fare is limited at that season and his animal food almost lacking. Winter in the North is all very well for the hairy and downy cousins that like to hammer frozen tree-trunks for frozen grubs; but our red-headed friend does not eat grubs by preference. Rather than change his habits he will change his boarding-place. So he is a migratory woodpecker, though the woodpeckers are naturally home-loving birds, and do not migrate from preference. If, however, he can lay up a store of vegetable or animal food, he can winter in any climate. Hoarding is thus an invention as important to the woodpecker world as electric cars and telephones are to men. The probabilities are that this is a recent improvement in the red-head’s ways of living.

Another set of facts increases the probabilities of our supposition. It is a very delicate subject to handle because it affects the reputation of a family in good standing; but there is positive proof that sometimes the red-head has been guilty of crimes which would give a man a full column in the newspapers with staring headlines. If such deeds were not a thousand times less common among woodpeckers than they are among men the red-head would be declared an outlaw. He has been proved to be a hen-roost robber, a murderer, and a cannibal. In Florida he has sucked hen’s eggs. In Iowa he has been seen to kill a duckling. There is a record in Ohio that he pecked holes in the walls of the eaves swallow’s nest and stole all the eggs, and that he was finally killed in the act of robbing a setting hen’s nest. Within the space of fifteen years, from Montana, Georgia, Colorado, New York, and Ontario, in addition to the records mentioned already from Florida, Ohio, and Iowa, come accounts of his stealing birds’ eggs and murdering and eating other birds. The evidence is indisputable.

It is charity to suppose that this is the work of natural criminals, or of degenerate, under-witted, or demented woodpeckers. Why should there not be such individuals among birds? One point is certain: so notable a habit could not long escape detection, since it is a barnyard crime. He who robs hen’s nests gets caught – if he is a bird. Either these occurrences are very rare, not seen because of their extreme rarity, or they indicate a new custom just coming in. And the same is true of the habit of hoarding food; it is rare, or it is new.

The frequency of such occurrences can be determined only by observation; but the time of their origin might be approximated in another way. If we could fix the date when the bird could not have done what he is now doing for simple lack of opportunity, we might say that the habit has been acquired since a certain date – as we have said of the English sparrow eating maize, of the chimney swift nesting in chimneys, and the cliff swallow building under the eaves. But we have no such help on the case of the red-head, which never has been without opportunities to get birds’ eggs and to kill other birds.

But there is a parallel case in another species where the date of an acquired habit can be proved. In Florida the red-bellied woodpecker has earned the names Orange Borer and Orange Sapsucker because he eats oranges. It is true that he is not charged with doing damage, because he attacks only the over-ripe and unmarketable fruit; it is known that the habit is not general yet, for even where the birds are abundant only a single bird or a pair will be found eating oranges, and always the same pair, proving that it is a habit not yet learned by all of the species; close observers declare, too, that it is but a few years since the bird took up the habit; and, finally, we know that this must be the case, for, though the wild orange was introduced by the Spaniards, the sweet fruit was not extensively cultivated until recently. Here is a habit which undoubtedly has been acquired within twenty years or so, which will in all probability increase until instead of being the exception it is the rule.

Why may not the red-head’s occasional cannibalism, unless this is mere individual degeneracy, and his more common custom of hoarding be habits that he is acquiring? Why, indeed, may not the Californian woodpecker’s distinguishing trait be a habit which began like these among a few birds here and there, wiser or more progressive than the rest, and which in time became general and established? Why may not the two observed instances of the Lewis’s woodpecker be examples of a similar habit just beginning? The very differences in their methods point to that explanation. The Lewis’s woodpecker that had seen the Carpenter’s work tried to imitate him; the one that lived outside his range adopted a way of his own, unnoticed before among woodpeckers, and shelled and quartered his nuts before he stored them.

It is remarkable that these four woodpeckers are cousins; they belong to the same genus, and they have essentially the same structure, tastes, and habits. Why should it be strange if their minds were alike too? if they had a natural bent toward accumulativeness, and a natural desire to try new wrinkles? We are sure that one of them has acquired a new habit within a few years. Why may we not suppose as a basis and a spur to further investigation that the others also are acquiring ways new and strange?