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.