With the exception of the California big tree, each tree species is preyed5 upon by scores, and many species by hundreds, of injurious and deadly insects. Five hundred kinds of insects[Pg 194] are known to prey4 upon the oak, and a complete count may show a thousand kinds. Many of these insects multiply with amazing rapidity, and at all times countless6 numbers of these aggressive pests form warrior7 armies with which the woodpecker must constantly contend.
In this incessant8 struggle with insects the woodpecker has helpful assistance from many other bird families. Though the woodpecker gives general attention to hundreds of kinds of insects, he specializes on those which injure the tree internally,—which require a surgical9 operation to obtain. He is a distinguished specialist; the instruments for tree-surgery are intrusted to his keeping, and with these he each year performs innumerable successful surgical operations upon our friends the trees.
Woodpeckers are as widely distributed as forests,—just how many to the square mile no one knows. Some localities are blessed with a goodly number, made up of representatives from three or four of our twenty-four woodpecker species. Forest, shade, and orchard10 trees receive their impartial11 attention. The annual[Pg 195] saving from their service is enormous. Although this cannot be estimated, it can hardly be overstated.
A single borer may kill a tree; so, too, may a few beetles13; while a small number of weevils will injure and stunt14 a tree so that it is left an easy victim for other insects. Borers, beetles, and weevils are among the worst enemies of trees. They multiply with astounding15 rapidity and annually16 kill millions of scattered17 trees. Annually, too, there are numerous outbreaks of beetles, whose depredations18 extend over hundreds and occasionally over thousands of acres. Caterpillars19, moths21, and saw-flies are exceedingly injurious tree-pests, but they damage the outer parts of the tree. Both they and their eggs are easily accessible to many kinds of birds, including the woodpeckers; but borers, beetles, and weevils live and deposit their eggs in the very vitals of the tree. In the tree's vitals, protected by a heavy barrier of wood or bark, they are secure from the beaks22 and claws of all birds except Dr. Woodpecker, the chief surgeon of the forest. About the only opportunity that[Pg 196] other birds have to feed upon borers and beetles is during the brief time they occupy in emerging from the tree that they have killed, in their flight to some live tree, and during their brief exposure while boring into it.
Beetles live and move in swarms23, and, according to their numbers, concentrate their attack upon a single tree or upon many trees. Most beetles are one of a dozen species of Dendroctonus, which means "tree-killer." Left in undisturbed possession of a tree, many mother beetles may have half a million descendants in a single season. Fortunately for the forest, Dr. Woodpecker, during his ceaseless round of inspection24 and service, generally discovers infested25 trees. If one woodpecker is not equal to the situation, many are concentrated at this insect-breeding place; and here they remain until the last dweller27 in darkness is reached and devoured28. Thus most beetle12 outbreaks are prevented. Now and then all the conditions are favorable for the beetles, or the woodpecker may be persecuted29 and lose some of his family; so that, despite his utmost efforts, he fails to[Pg 197] make the rounds of his forest, and the result is an outbreak of insects, with wide depredations. So important are these birds that the shooting of a single one may allow insects to multiply and waste acres of forest.
During the periods in which the insects are held in check the woodpecker ranges through the forest, inspecting tree after tree. Many times, during their tireless rounds of search and inspection, I have followed them for hours. On one occasion in the mountains of Colorado I followed a Batchelder woodpecker through a spruce forest all day long. Both of us had a busy day. He inspected eight hundred and twenty-seven trees, most of which were spruce or lodge-pole pine. Although he moved quickly, he was intensely concentrated, was systematic30, and apparently31 did the inspection carefully. The forest was a healthy one and harbored only straggling insects. Now and then he picked up an isolated33 insect from a limb or took an egg-cluster from a break in the bark on a trunk. Only two pecking operations were required. On another occasion I watched a hairy woodpecker[Pg 198] spend more than three days upon one tree-trunk; this he pecked full of holes and from its vitals he dragged more than a gross of devouring34 grubs. In this case not only was the beetle colony destroyed but the tree survived.
WOODPECKER HOLES IN A PINE INJURED BY LIGHTNING WOODPECKER HOLES IN A PINE INJURED BY LIGHTNING
Woodpecker holes commonly are shallow, except in dead trees. Most of the burrowing35 or boring insects which infest26 living trees work in the outermost36 sapwood, just beneath the bark, or in the inner bark. Hence the doctor does not need to cut deeply. In most cases his peckings in the wood are so shallow that no scar or record is found. Hence a tree might be operated on by him a dozen times in a season, and still not show a scar when split or sawed into pieces. Most of his peckings simply penetrate37 the bark, and on living trees this epidermis38 scales off; thus in a short time all traces of his feast-getting are obliterated39. I have, however, in dissecting40 and studying fallen trees, found a number of deep holes in their trunks which woodpeckers had made years before the trees came to their death. In one instance, as I have related in "The Story of a Thousand-Year Pine" in "Wild Life on the [Pg 199] Rockies," a deep oblong hole was pecked in a pine nearly eight hundred years before it died. The hole filled with pitch and was overgrown with bark and wood.
Woodpeckers commonly nest in a dead limb or trunk, a number of feet from the ground. Here, in the heart of things, they excavate41 a moderately roomy nest. It is common for many woodpeckers to peck out a deep hole in a dead tree for individual shelter during the winter. Generally neither nest nor winter lodging42 is used longer than a season. The abandoned holes are welcomed as shelters and nesting-places by many birds that prefer wooden-walled houses but cannot themselves construct them. Chickadees and bluebirds often nest in them. Screech43 owls44 frequently philosophize within these retreats. On bitter cold nights these holes shelter and save birds of many species. One autumn day, while watching beneath a pine, I saw fifteen brown nuthatches issue from a woodpecker's hole in a dead limb. Just what they were doing inside I cannot imagine; the extraordinary number that had gathered therein made the incident [Pg 200]so unusual that for a long time I hesitated to tell it. However, early one autumn, Mr. Frank M. Chapman climbed up the mountainside to see me, and, while resting on the way up, he beheld45 twenty-seven nuthatches emerge from a hole in a pine.
By tapping against dead tree-trunks I have often roused Mother Woodpecker from her nest. Thrusting out her head from a hole far above, she peered down with one eye and comically tilted46 her head to discover the cause of the disturbance47. With long nose and head tilted to one side, she had both a storky and a philosophical48 appearance. The woodpecker, more than any other bird of my acquaintance, at times actually appears to need only a pair of spectacles upon his nose in order fully32 to complete his attitude and expression of wisdom.
The downy woodpecker, the smallest member of a family of twenty-four distinguished species, is the honored one. He is a confiding49 little fellow and I have often accompanied him on his daily rounds. He does not confine his attacks to the concealed50 enemies of the trees, but preys51 freely[Pg 201] upon caterpillars and other enemies which feast upon their leaves and bloom. He appears most content close to the haunts of man and spends much of his time caring for orchards52 and cleaning up the shade trees. One morning in Missouri a downy alighted against the base of an apple tree within a few feet of where I was standing53. He arrived with an undulating flight and swept in sideways toward the trunk, as though thrown. Spat54! he struck. For a moment he stuck motionless, then he began to sidle round and up the trunk. Every now and then he tapped with his bill or else stopped to peer into a bark-cavity. He devoured an insect egg-cluster, a spider, and a beetle of some kind before ascending55 to the first limb.
Just below the point of a limb's attachment56 he edged about, giving the tree-trunk a rattling57 patter of taps with his bill. He was sounding for something. Presently a spot appeared to satisfy him. Adjusting himself, he rained blows with his pick-axe bill upon this, tilting58 his head and directing the strokes with an apparently automatic action, now and then giving a side[Pg 202] swipe with his bill, probably to tear out a splinter or throw off a chip. In six minutes his prey was evidently in sight. Then he enlarged the hole and slightly deepened it vertically59. Pausing, he thrust his head into the hole and his bill into a cavity beyond. With a backward tug60 he pulled his head out, then his bill, and at last his extended tongue with a grub impaled61 on its barbed point. This grub was dragged from the bottom of a crooked62 gallery at a point more than three inches beyond the bottom of the pecked hole. A useful bread-getting tool, this tongue of his,—a flexible, extensible spear.
In another tree he uncovered a feast of ants and their eggs. Once a grasshopper63 alighted against another tree-trunk up which he was climbing. Downy seized him instantly. In one tree-top he consumed an entire tent-caterpillar colony. In four hours he examined the trunks, larger limbs, and many of the smaller ones of one hundred and thirty-eight apple trees. In this time he made twenty-two excavations64, five of which were large ones. Among the insects devoured were beetles, ants, their eggs and their[Pg 203] aphids, a grasshopper, a moth20 or two, and a colony of caterpillars. I followed him closely, and frequently was within a few feet of him. Often I saw his eyes, or rather one eye at a time; and a number of times I imagined him about to look round and with merry laugh fly away, for he frequently acted like a happy child who is closely watching you while all the time merrily pretending not to see you. Yet, in all those four hours, he did not do a single thing which showed that he knew of my nearness or even of my existence!
Examining each tree in turn, he moved down a long row and at the end flew without the slightest pause to the first tree in the next row. From here he examined a line of trees diagonally across the orchard to the farther corner. Here he followed along the outside row until he flew away. The line of his inspection, from the time I first saw him until he flew away, formed a big letter "N."
During a wind-storm in a pine forest a dead tree fell near me and a flying limb knocked a downy, stunned65, to the earth, by my feet. On[Pg 204] reviving in my hands, he showed but little excitement, and when my hands opened he pushed himself off as though to dive to the earth; but he skimmed and swung upward, landing against a tree-trunk about twenty feet distant. Up this he at once began to skate and sidle, exploring away as though nothing had happened and I were only a stump66.
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1
emblematic
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| adj.象征的，可当标志的；象征性 | |
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distinguished
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| adj.卓越的，杰出的，著名的 | |
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3
supervision
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| n.监督，管理 | |
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prey
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| n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨 | |
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preyed
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| v.掠食( prey的过去式和过去分词 )；掠食；折磨；（人）靠欺诈为生 | |
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6
countless
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| adj.无数的，多得不计其数的 | |
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7
warrior
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| n.勇士，武士，斗士 | |
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8
incessant
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| adj.不停的，连续的 | |
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9
surgical
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| adj.外科的，外科医生的，手术上的 | |
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10
orchard
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| n.果园，果园里的全部果树，(美俚)棒球场 | |
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11
impartial
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| adj.(in,to)公正的，无偏见的 | |
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12
beetle
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| n.甲虫，近视眼的人 | |
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beetles
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| n.甲虫( beetle的名词复数 ) | |
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14
stunt
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| n.惊人表演，绝技，特技；vt.阻碍...发育，妨碍...生长 | |
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15
astounding
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| adj.使人震惊的vt.使震惊，使大吃一惊astound的现在分词) | |
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16
annually
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| adv.一年一次，每年 | |
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17
scattered
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| adj.分散的，稀疏的；散步的；疏疏落落的 | |
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18
depredations
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| n.劫掠，毁坏( depredation的名词复数 ) | |
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19
caterpillars
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| n.毛虫( caterpillar的名词复数 )；履带 | |
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20
moth
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| n.蛾，蛀虫 | |
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21
moths
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| n.蛾( moth的名词复数 ) | |
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22
beaks
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| n.鸟嘴( beak的名词复数 )；鹰钩嘴；尖鼻子；掌权者 | |
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23
swarms
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| 蜂群，一大群( swarm的名词复数 ) | |
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24
inspection
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| n.检查，审查，检阅 | |
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25
infested
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| adj.为患的，大批滋生的（常与with搭配）v.害虫、野兽大批出没于( infest的过去式和过去分词 )；遍布于 | |
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infest
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| v.大批出没于；侵扰；寄生于 | |
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dweller
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| n.居住者，住客 | |
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28
devoured
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| 吞没( devour的过去式和过去分词 )； 耗尽； 津津有味地看； 狼吞虎咽地吃光 | |
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29
persecuted
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| （尤指宗教或政治信仰的）迫害(~sb. for sth.)( persecute的过去式和过去分词 )； 烦扰，困扰或骚扰某人 | |
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30
systematic
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| adj.有系统的，有计划的，有方法的 | |
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31
apparently
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| adv.显然地；表面上，似乎 | |
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32
fully
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| adv.完全地，全部地，彻底地；充分地 | |
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33
isolated
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| adj.与世隔绝的 | |
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34
devouring
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| 吞没( devour的现在分词 )； 耗尽； 津津有味地看； 狼吞虎咽地吃光 | |
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35
burrowing
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| v.挖掘（洞穴），挖洞( burrow的现在分词 )；翻寻 | |
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36
outermost
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| adj.最外面的，远离中心的 | |
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37
penetrate
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| v.透(渗)入；刺入，刺穿；洞察，了解 | |
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38
epidermis
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| n.表皮 | |
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39
obliterated
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| v.除去( obliterate的过去式和过去分词 )；涂去；擦掉；彻底破坏或毁灭 | |
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40
dissecting
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| v.解剖（动物等）( dissect的现在分词 )；仔细分析或研究 | |
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41
excavate
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| vt.挖掘，挖出 | |
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42
lodging
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| n.寄宿，住所；(大学生的)校外宿舍 | |
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43
screech
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| n./v.尖叫；(发出)刺耳的声音 | |
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44
owls
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| n.猫头鹰( owl的名词复数 ) | |
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45
beheld
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| v.看，注视( behold的过去式和过去分词 )；瞧；看呀；（叙述中用于引出某人意外的出现）哎哟 | |
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46
tilted
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| v. 倾斜的 | |
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47
disturbance
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| n.动乱，骚动；打扰，干扰；(身心)失调 | |
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48
philosophical
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| adj.哲学家的，哲学上的，达观的 | |
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49
confiding
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| adj.相信人的，易于相信的v.吐露（秘密，心事等）( confide的现在分词 )；（向某人）吐露（隐私、秘密等） | |
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50
concealed
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| a.隐藏的，隐蔽的 | |
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51
preys
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| v.掠食( prey的第三人称单数 )；掠食；折磨；（人）靠欺诈为生 | |
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52
orchards
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| （通常指围起来的）果园( orchard的名词复数 ) | |
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53
standing
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| n.持续，地位；adj.永久的，不动的，直立的，不流动的 | |
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54
spat
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| n.口角，掌击；v.发出呼噜呼噜声 | |
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55
ascending
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| adj.上升的，向上的 | |
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56
attachment
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| n.附属物，附件；依恋；依附 | |
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57
rattling
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| adj. 格格作响的, 活泼的, 很好的 adv. 极其, 很, 非常 动词rattle的现在分词 | |
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58
tilting
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| 倾斜，倾卸 | |
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59
vertically
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| adv.垂直地 | |
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60
tug
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| v.用力拖(或拉)；苦干；n.拖；苦干；拖船 | |
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61
impaled
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| 钉在尖桩上( impale的过去式和过去分词 ) | |
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62
crooked
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| adj.弯曲的；不诚实的，狡猾的，不正当的 | |
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63
grasshopper
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| n.蚱蜢，蝗虫，蚂蚱 | |
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64
excavations
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| n.挖掘( excavation的名词复数 )；开凿；开凿的洞穴（或山路等）；（发掘出来的）古迹 | |
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65
stunned
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| adj. 震惊的，惊讶的 动词stun的过去式和过去分词 | |
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66
stump
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| n.残株，烟蒂，讲演台；v.砍断，蹒跚而走 | |
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