440 



P I C U S. 



smallest genus which have the especial protection of 

 the wood of trees committed to them. The wood- 

 peckers, which we find in greatest abundance in tem- 

 perate, and even in cold latitudes, stand at the head 

 of this grand division of birds, which ought, in a 

 natural system, to form a separate family ; for though 

 some genera are zygodactylic, and others anizo- 

 dactylic, yet this difference of the feet is not sufficient 

 foundation for distinguishing the groups. Besides 

 this, we have seen that the zygodactylic have the 

 feet differently modified, and consequently adapted 

 for different kinds of motion upon the trees ; some of 

 the woodpeckers, and also of the genus under con- 

 sideration, having only three toes, while the typical 

 birds have four. From the difference in size between 

 the outer and inner toe in the feet of the three-toed 

 birds, the outer toe answers nearly the same purpose 

 as the outer and middle toes of the anizodactylic 

 foot. There is also a closer approach than this in 

 the structure ; for the two outer toes of the anizodac- 

 tylic foot are united a considerable way at the bases. 

 Both this foot and the three-toed foot have therefore 

 a point of support less, than is possessed by the four- 

 toed zygodactylic foot ; and it is a remarkable fact in 

 nature's mechanics, that whenever an organ is to have 

 motion in an additional number of directions, the 

 structure of the organ is always simplified. The 

 woodpeckers, whose most laborious work, that of 

 punching large holes in the trees, requires that they 

 should remain firm and stationary, in an upright posi- 

 tion, for a considerable time, have the feet with four 

 points of support upon each, nearly equally balanced 

 backwards and forwards. The parrots, and other 

 birds which climb by grasping, and rarely if ever 

 change their position by simple motion, have the 

 grasp or clutch of the foot of the very best form for 

 their habit. The birds which have the points of sup- 

 port in the feet reduced to three, whether the outer 

 one in front is one single toe, or two partially united, 

 are on the other hand formed for running in almost 

 every direction upon the stems or branches of trees, 

 without clutching or any other means, except holding 

 on by the claws ; and they may be considered as 

 really having the hardest labour of the whole. The 

 woodpecker may be compared to a mason on his 

 scaffold ; the parrot to a gardener on a tree gather- 

 ing apples ; but the bird which runs on the bark has 

 nothing corresponding to it in human action. 



We have purposely selected such names as should 

 bring those three genera of birds together, in order 

 that the grounds of all their agreements and disagree- 

 ments might be at once understood by the reader ; 

 and we have entered somewhat at length into the 

 particulars, because these birds, taken in conjunction 

 with the trees which their labours so tend to pre- 

 serve, are among the most interesting productions of 

 nature. 



PICUS woodpecker. An extensive and well- 

 defined genus of zygodactylic or yoke-footed birds, 

 distributed over most parts of the globe, and perform- 

 ing a very important function in the: economy of 

 nature. Woodpeckers are generally speaking hand- 

 some birds, neatly and stoutly made, remarkably firm 

 in the texture of their plumage, and generally speak- 

 ing handsomely coloured. 



The genus are very easily defined, both by their 

 structure and their habits. The bill is long, straight, 

 supported by angular ridges, and remarkably hard and 

 firm in its texture, especially toward the tip, which is 



however generally worn smooth by the severe laboti! 

 which the birds have to undergo ; the tongue ii 

 slender and very extensile, being capable of beins; 

 projected beyond the tip of the bill, by the action o 

 the long horns of the o* hi/oides, or proper bone o 

 this tongue. The point of this tongue is doubly fur 

 nished for capturing the prey upon which the bird 

 feed : it is beset with cartilaginous barbs, approach 

 ing to the consistency of horn, and inclined backwards 

 and it is furnished with a glutinous secretion, by mean 

 of which it can readily take up small substances, an< 

 convey them into the mouth of the bird, when th 

 tongue is drawn backwards ; the tongue can be with 

 drawn with great rapidity, by means of two muscle 

 which are coiled round the trachea ; and when thcs 

 act, the horns of the os /tyo'idcs are drawn till the; 

 stand directly upwards, and the tongue is folded bac 

 towards the entrance of the gullet. This action c 

 the tongue, by the muscles which move it not beini 

 in any way inserted in the bones of the head an 

 neck, is quite a distinct motion from that of the bii 

 and may be carried on independently of it ; th 

 muscles which move the bill and head are still mor 

 powerful, so that the point of the bill acts like 

 chisel or rather like a little pickaxe, by means ( 

 which the bird very speedily punches a hole in th 

 wood of a tree. This is the means by which the rac 

 obtain by far the greater part of their food, whic 

 consists of insects and larvye, especially the latter 

 and those larvae are most abundant in trees after the 

 have passed the maturity of their vigour, and ai 

 in an incipient state of decay. The rapidity wit 

 which a woodpecker pecks away at its work is almoi 

 incredible, and the strokes cannot be counted, nor 

 it easy to see the motion of the head and neck. Th 

 feet are well adapted for holding on, or ascending th 

 vertical trunk of a tree ; but they are not so we 

 adapted for descent, so that when the bird take 

 a more downward direction it must, generally speal 

 ing, have recourse to the wing. It can however mak 

 its way laterally with great ease ; and a woodpecke 

 can get round the bole of a tree much faster than on 

 who is observing it can get round the root. 



Woodpeckers have in fact the especial charge < 

 forests which are allowed to perish by natural decaj 

 In such forests they are exceedingly numerous ; an 

 in most parts of the world, whether the temperatur 

 is hot, temperate, or cold, woodpeckers arc there t 

 perform their labours. In America they are exceec 

 ingly numerous ; though they are most so in Nort 

 America, inasmuch as many of the trees there ar 

 very subject to decay. They occur also in all th 

 wooded parts of Europe, of continental Asia, c 

 some parts at least of Africa, and of the easter 

 islands more immediately connected with Asia. W 

 are not aware that any true woodpeckers, or at mos 

 onlv one species, have been hitherto found in Nei 

 Holland, or in the islands of the Pacific ; and i 

 should seem that decaying trees in these places 

 and also in many parts of Africa, are attacked by in 

 sects in a different manner from what they are i 

 those countries where woodpeckers are abundam 

 The attack there is made by the mature insect 

 mining into the heart of the tree, reducing the intei 

 nal part to dust, and leaving the external crust sounc 

 whereas it is the Kirvje which are hatched in th 

 decaying wood, or which mine between the woo 

 and the bark, of which the woodpeckers have charge 



Their labours in those countries where they aboum 



