Part 6

These questions are answered by studying the bones of the tongue, for without bones it could not be guided as swiftly and surely as it is. Indeed, all tongues have bones in them, as you will discover by cutting carefully the slices near the root of an ox-tongue; but no other creature has such long and elaborate tongue-bones as some of the woodpeckers. They are the slenderest and most delicate little bony rods, joined end to end, but not really hinged nor needing to be, because they are so elastic. Here are the bones of a flicker's tongue. The little knob at the end, marked _a_, bore the horny point of the tongue and directed it; the straight shaft marked _b_ was inside the round part of the tongue as it lay within the bird's mouth; but what was done with these two long branches, fully three quarters of the entire length of the bones? They are too sharply curved to pass down the bird's throat, and, not being jointed, they cannot be doubled back in his mouth. They were tucked away very neatly and curiously. As the hyoid or tongue-bone lies in the mouth its branches diverge just in front of the gullet, and, traveling along the inner sides of the fork of the lower jaw, pass up over the top of the skull, looking in their sheath of muscles like two tiny whipcords. But still the bones are too long by perhaps half an inch for the place they occupy, and the ends must be neatly disposed of. Usually both pass to the right nasal opening and along the hollow of the upper mandible. Very rarely they may curl down around the eyeball in a spiral spring. So when the flicker thrusts out his tongue he feels the pull in the end of his nose, for the tip of the tongue being run out, the long slender bones are drawn out of their hiding-places, down over the skull until they lie flat along the roof of his mouth. As soon as he wishes to shut his bill, back fly the little bones guided by their hollow sheaths of elastic muscle into their hiding-place in the top of the bill. The muscular covering is a part of the same soft envelope that we saw lying in wrinkles at the root of the tongue. It covers the whole length of the little bones just as the woven outside covers an elastic cord.

Not all woodpeckers have tongues precisely like this. The sapsucker's is the shortest of any, and reaches barely beyond the hinge of the jaws. In the Lewis's woodpecker and others of his genus the branches of the hyoid extend part-way up the back of the skull but in the kinds that live principally upon borers they are very long and resemble the flicker's in arrangement. The only other North American birds that have a tongue built upon this plan are the hummingbirds, in which also it is extensile. The flicker, in proportion to his size, has the longest tongue of any bird known.

XV

HOW EACH WOODPECKER IS FITTED FOR HIS OWN KIND OF LIFE

We have studied the woodpeckers at some length: first, what all of them do; next, what some that are peculiar in their ways do; lastly, how each is fitted for a particular kind of life. At first we were inclined to think they were all alike; but now we begin to see that there are very real differences between them,--in tails, feet, bills, and tongues, and at the same time in their food and habits.

The flicker's tail is less sharply curved than that of any other woodpecker,--a sign that he is probably not exclusively a tree-dweller; his bill is curved and rounded, a pick-axe rather than a drill,--an indication that he does not dig for grubs; his feet do not tell us much; but his long extensile tongue shows that, whatever he feeds upon, he seeks it in holes. We find a tongue like this in no other bird, but among mammals the aard-vark, the ant-bear, and the pangolins are all similarly equipped, and all live on ants which they extract from their mounds and burrows in hundreds by means of these round, sticky, and extensile tongues. This is precisely the way the flicker gets his living. He lives principally upon the ground or near it, pecks very little except when digging his nest, and feeds largely upon ants, thrusting his head into the ant-hills and drawing out the ants glued to his tongue rather than speared by it. As he has been known to eat three thousand ants for a meal, we see how much easier this is than spearing them one by one.

The red-head is another type. The bill is still nearly of the pick-axe model, the feet not especially different from the flicker's, the tail rather better adapted to life on a tree-trunk, and the tongue entirely unlike the flicker's,--not very extensile and heavily clothed near the tip with long, thick, recurved bristles. We infer that though he may climb well, he is not a drilling woodpecker to any great extent, and that his tongue is adapted neither to extracting borers nor to eating ants from their burrows. His habits bear out the inference. He is arboreal, but his food is either vegetable or picked up from the surface, rasped up rather than speared.

The sapsucker presents still another variation. The points to the tail feathers are more acuminate and the tail itself more resembles that of the tree-dwelling woodpeckers in shape; the feet are fitted for clinging to the trunk; the bill, now perfectly straight and no longer smoothly rounded but buttressed by strong angles that spring from the base and run down toward the tip, is the bill of a woodpecker that lives by drilling; but the tongue is wholly unadapted to catching grubs. What kind of food can an arboreal woodpecker with a drilling bill find upon a tree-trunk when his tongue can be extended only a fifth of an inch, and is furnished with a brush of bristles at the end? We have answered that question before: he eats the inner bark of trees and laps up the sap, for which this brushy tip is excellently fitted. It has been observed that the tongue much resembles the tongues of insect-eating birds, which cannot be extended beyond the end of the bill. It is true that the sapsucker catches great numbers of insects, taking them on the wing like a flycatcher. But he also eats nearly as many ants as the flicker, though their tongues are totally unlike. We have made the mistake perhaps of thinking that ants live only underground and can be obtained only by tongues like those of the flicker and the ant-bear, which hunt them there. But ants are abundant on the surface of the ground, and they excavate long tunnels in rotten wood. The black bear is a famous ant-hunter, yet his tongue is like a dog's and he gets his ants by lapping them up after he has torn open the rotten logs in which they live. This is the way that the sapsucker obtains his ants, and the brush of stiff hairs is a help to him in such work. We see, then, that it is not so much the food as the manner of feeding that explains the form of the tongue.

The downy and the hairy are a step farther along in their development. The fourth toe is longer than the others, a condition that we do not find in any of the woodpeckers not strictly arboreal; the tail is of the improved pattern, holding by a brush of bristles rather than by one stiff point at the end of each feather; the bill is heavier, broader at the base, more heavily ridged, and in every way a stronger tool; and the tongue is highly extensible and of the spear pattern, sharp-pointed and barbed with recurved hooks. Everything about these birds indicates that they are fitted to live on tree-trunks and to dig for borers. This, indeed, is what they do.

But the great logcock and the ivory-billed woodpecker, though of the same type as the other larvae-eating woodpeckers, are more highly developed along the same line. We notice the great strength of the feet; the claws, as large and as sharp as a cat's; the enormous weight and strength of the bill, compared with that of the other woodpeckers, which enables them to cut into the hardest wood and even into frozen green timber; and the great development of the tail, which now becomes a strong spring to support and aid the bird in his work.

As we try to group these particulars under general heads, we see that we have observed three things:--

_That the structure of a bird is adapted to its kind of life._

_That the structure varies by small degrees with the kind of life._

_That the kind of life is conditioned largely upon the kind of food and upon the method of procuring it, more particularly the latter._

These are not so much different truths as three aspects of one truth. When we study the first we see why birds are grouped together into orders and families: we study their resemblances. When we observe the second we see why they are divided into species, for we note their differences. But when we consider the third and reflect that birds have the power to choose new kinds of food or new places and means of getting it, we see how it is that there can come to be new kinds of birds, new subspecies and species, springing up from time to time. Wonderful and improbable as it seems, there is more reason to believe than there is to doubt that new kinds of animals and plants are constantly in process of making; that the laws of change are constantly at work, adapting creatures to their surroundings or crushing them out of existence because they will not learn new ways. And it is probable that these differences which we mark in the woodpeckers have been the result of efforts to adapt themselves to a peculiar kind of life where food was abundant; and also that by acquired habits and by acquired tastes for different kinds of foods they will be subject to still further variations in the future.

XVI

THE ARGUMENT FROM DESIGN

But if the birds are making themselves into new species, where is the place for God in the universe? Did not God make all kinds of creatures in the beginning? How can they go on being made without God?

These are questions every one ought to ask, but--did God leave his world after He had made it and go a long way off? Did He wind it up like a watch to go till it should run down? Is the world a machine, or is it alive?

Long ago the wise and good man Socrates argued that if you did not know there was a God at all, you could at least infer it because everything was so wonderfully made. "There is our body," said he: "every part of it so perfect and so reasonable. Consider how the eyes not only please us with agreeable sensations but are protected in every way. The eyebrows stand like a thicket to keep the perspiration from them, the lids are a curtain to shut out too great light, the lashes screen them from dust,--everything is planned for some wise and reasonable end. And where the evidence of design is so convincing must we not believe that there was a Designer?" Words like these he spoke, and we know because everything is so perfectly contrived that there must have been a contriver, who knew all from the beginning. We are compelled to believe that there is a God.

Shall we believe it less because we find in the creatures about us intelligence and the power to care for their own lives? Has God gone on a visit because these living creatures are looking out for themselves? Were they made less perfectly in the beginning because when new conditions surround them they are able to change to meet the strange requirements? This is not less evidence of a Designer, but more. It was long said that the existence of a watch was proof of a watchmaker who had planned and put together all the parts so that they worked harmoniously. But if the watch had the power to grow small to fit a small pocket, or large to fit a large one, to become luminous by night, and to correct its own time by the sun instead of being regulated by outside interference, what should we have said--that it was proof there was no watchmaker? or that it showed a far more skillful one, since he could make a living, self-regulating, adaptive watch?

And so of the world and the creatures in it. Every evidence we get that they can care for themselves, that they can adapt themselves to new conditions, that they are intelligent and reasonable, capable of improvement in habits or in structure, is so much surer proof that a wise God made them what they are. Evolution--for that is the name by which we call these changes--does not take God out of the universe but makes the need of Him stronger. The argument from design is immensely strengthened when we consider that we have not only an obedient machine acting according to a few fundamental rules, but one that is intelligent also and capable of self-modification.

APPENDIX

_Explanation of Terms._

_a._ Forehead; _b._ crown; _c._ occiput; _d._ nape; _e._ chin; _f._ throat; _g._ jaw-patch, or mustache.

_Occipital_ means "on the occiput."

_Nuchal_ means "on the nape."

_Primaries_ are the nine or ten wing-quills borne upon the last joint of the wing.

_Secondaries_ are the wing-quills attached to the fore-arm bones.

_Tertiaries_ are the wing-quills springing from the upper arm bones.

_Wing coverts_ are the shorter lines of feathers overlapping these long quills.

_Tail coverts_ are the lengthened feathers that overlap the root of the tail both above and below, called respectively upper and under tail coverts.

_Ear coverts_ are the feathers that over-lie the ear, often specially modified or colored.

_Rump_, the space between the middle of the back and the root of the tail.

[M] is the sign used to indicate the male sex.

[F] is the sign used to indicate the female sex.

A _subspecies_ is a geographical race, modified in size, color, or proportions chiefly by the influence of climate. These variations are especially marked in non-migratory birds of wide distribution, subject, therefore, to climatic extremes. The Downy and the Hairy Woodpeckers, for example, are split up into numerous races. It should be remembered that when a species has been separated into races, or subspecies, all the subspecies are of equal rank, even though they are differently designated. The one originally discovered and first described bears the old Latin name which consisted of two words, while the new ones are designated by triple Latin names--the old binomial and a new name in addition. The binomial indicates the form first described. The forms designated by trinomials may be equally well known, abundant, and widely distributed. For example, among the woodpeckers, the northern form of the Hairy Woodpecker was first discovered and bears the name _Dryobates villosus_; but the first Downy Woodpecker described was a southern bird, and the northern form was not separated until a few years ago, so that the southern bird is the type, and the northern one bears the trinomial, _Dryobates pubescens medianus_.

_North America_, by the decision of the American Ornithologists' Union, is held to include the continent north of the present boundary between Mexico and the United States, with Greenland, the peninsula of Lower California, and the islands adjacent naturally belonging to the same.

The following key and descriptions will enable the student to identify any woodpecker known to occur within these limits:

A. KEY TO THE WOODPECKERS OF NORTH AMERICA.

Family characteristics: color always striking, usually in spots, bars, or patches of contrasting colors, especially black and white. Sexes usually unlike; male always with some portion of red or yellow about head, throat, or neck. Tails stiff, rounded, composed of ten fully developed pointed feathers (and two undeveloped feathers). Wings large, rounded, with long, conspicuous secondaries, and short coverts. Bill straight, stout, of medium length. Toes four, arranged in pairs, except in the three-toed genus. Iris brown, except when noted. Marked by a habit of clinging to upright surfaces and digging a deep hole in a tree-trunk for nesting. Eggs always pearly white.

I. Very large--18 inches _or more_; conspicuously crested. A. II. Medium or small--14 inches _or less_; never crested. B.

A. a^1 Bill gleaming _ivory white_; fourth toe decidedly longest. Ivory-billed Woodpecker. 1.

a^2 Bill _blackish_; fourth toe not decidedly longest. Pileated Woodpecker or Logcock. 14.

B. a^1 Toes three; [M] with _yellow_ crown. Three-toed Woodpeckers. 9 & 10.

a^2 Toes four; crown never yellow (b).

b^1 _Not spotted nor streaked either above or below_ (c).

c^1 Body clear black; _head white_. White-headed Woodpecker. 8.

c^2 Blue-black above; _rump white_; _head_ and _neck red_. Red-headed Woodpecker. 15.

c^3 Greenish black above, with _pinkish red belly_. Lewis's Woodpecker. 17.

c^4 Greenish black with _sulphur yellow forehead_ and _throat._ Californian Woodpecker. 16.

c^5 Glossy blue-black with _scarlet throat_ and _yellow belly_. Male of Williamson's Sapsucker. 13.

b^2 _Spotted with black or brown on breast and sides_, but not streaked nor barred with white (d).

d^1 _Brown_ spots on breast and sides; upper parts plain brown. Arizona Woodpecker. 7.

d^2 _Black_ spots on breast and sides; wings and tail brilliantly colored beneath (e).

e^1 Wings and tail _golden_ beneath; mustaches _black_ in male, wanting in female. Flicker. 21.

e^2 Wings and tail _golden_ beneath; mustaches _red_ in both sexes. Gilded Flicker. 23.

e^3 Wings and tail _golden red_ beneath; mustaches red. Red-shafted Flicker. 22.

e^4 Wings and tail _golden red_ beneath; mustaches red; crown brown. Guadalupe Flicker. 24.

b^3 _Streaked, spotted, or barred with white on back and wings_ (f).

f^1 _Back streaked_, _plain_, or _varied_, _never_ barred with white; wings _spotted_ with white (g).

g^1 _Clear_ white and black; _white streak down the back_ (h).

h^1 Medium size, 9-11 inches. Hairy Woodpecker. 2.

h^2 Small size, 6-7 inches. Downy Woodpecker. 3.

g^2 _Grayish_ white and black; _sides closely barred_ (i).

i^1 Back plain black, white _stripe_ down side of throat. Female of Arctic Three-toed Woodpecker. 9.

i^2 Back with interrupted white stripe, white _line_ down side of throat. Female of American Three-toed Woodpecker. 10. (NOTE.--The males are similar with the addition of the yellow crown. The three toes cannot ordinarily be seen in life.)

g^3 _Yellowish_ (often dingy or smutty), white and black; under parts yellowish; back varied with white, no line nor streak; _rump white_; _white wing-bars_ (j).

j^1 Breast with black patch; head of adult with red patches. Yellow-bellied Sapsucker. 11.

j^2 Breast and head red. Red-breasted Sapsucker. 12.

f^2 _Back barred with white_; wings spotted or barred with white (k).

k^1 Belly _white; ear coverts white_. Red-cockaded Woodpecker. 4.

k^2 Belly _white; forehead black_. Nuttall's Woodpecker. 6.

k^3 Belly _smoky brown_; forehead and breast same. Texan Woodpecker. 5.

k^4 Belly _sulphur or lemon yellow_. Female of Williamson's Woodpecker. 13.

k^5 Belly _pinkish red_. Red-bellied Woodpecker. 18.

k^6 Belly _yellow_, hind neck and forehead orange. Golden-fronted Woodpecker. 19.

k^7 Belly _yellow_, hind neck brown. Gila Woodpecker. 20.

B. DESCRIPTIONS OF THE WOODPECKERS OF NORTH AMERICA.

The following are descriptions of all the species of Woodpeckers found in North America, arranged in their proper genera and in the order given in the check list of the American Ornithologists' Union, 1895; with the range of species and subspecies as defined by the same authority or by Bendire's "Life Histories of North American Birds."

1. CAMPEPHILUS PRINCIPALIS, _Ivory-billed Woodpecker_. Glossy black except _white secondaries_ (very conspicuous) and white stripe from beneath ear down neck and shoulders; white nasal tufts; _bill white_. Both sexes crested; [M] with scarlet occipital crest, [F] with crest black. Iris yellow. 20 inches. Cypress swamps of Gulf States, locally distributed. The largest, shyest, and rarest of our woodpeckers.

2. DRYOBATES VILLOSUS, _Hairy Woodpecker_. Black and white. Upper parts glossy black with a broad _white stripe_ down the back; wings thickly spotted with white; under parts white; three outer pairs of tail feathers white; two white and two black stripes on sides of head; nasal tufts brownish white. [M] with scarlet occipital patch. 9-10 inches. Eastern United States except South Atlantic and Gulf States, with the following subspecies, all the races being resident the year round, and breeding in most places where they are found:--

a. _D. v. leucomelas_, _Northern Hairy Woodpecker_. 10-11 inches. Larger, whiter. British America.

b. _D. v. audubonii_, _Southern Hairy Woodpecker_. 8-8.5 inches. Smaller, more dingy white. South Atlantic and Gulf States.

c. _D. v. harrisii_, _Harris's Woodpecker_. 9-10 inches. Upper parts with less white, few wing spots, under parts soiled white or smoky brown; larger than next. Northwest coast, northern California to Alaska.

d. _D. v. hyloscopus_, _Cabanis's Woodpecker_. 8.5-9.5 inches. White stripe down back very wide; purer white below than _harrisii_; fewer wing spots than _leucomelas_ and _villosus_. Western United States, except northwest coast, east to the Rocky Mountains.

e. _D. v. monticola_, _Rocky Mountain Woodpecker_. 10-11 inches. Larger; more white spots near bend of wing and secondaries than _hyloscopus_, fewer than _villosus_; pure white below. Rocky Mountains west to Uintah Mountains, Utah.

3. DRYOBATES PUBESCENS, _Southern Downy Woodpecker_. Black and white; broad _white stripe_ down back; wings thickly spotted with white; under parts white. [M] with scarlet occipital patch. A miniature Hairy Woodpecker, differing only in having _four_ outer pairs of tail feathers more or less white and the _outermost barred_. 6.5 inches. Like the Hairy Woodpecker, the Downy and its subspecies are resident and breed wherever they occur. South Atlantic and Gulf States.

a. _D. p. gairdnerii_, _Gairdner's Woodpecker_. 6.75 inches. Bears same relation to Downy that Harris's does to Hairy Woodpecker; under parts smoky white; wings spots few. Pacific coast north to about lat. 55 deg.