IIVBERNATIOX. 



387 



Animal* 

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In quadra- 

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operations of the seasons. During the summer months 

 the fur is thin and short, and is scarcely ever an object 

 of pursuit; while during the winter, it possesses in 

 perfection all its valuable qualities. When the begin- 

 ning of winter is remarkable for its mildness, the far is 

 longer in >; ing. as the animal stands in no need of 

 the additional quantity for a covering ; but at soon as 

 the rigours of the season commence, the fleece speedily 

 increase* in the quantity and length of hair. This in- 

 crease i* sometimes very rapid in the hare and the rab- 

 bit, whose skins are seldom ripe in the fur until there 

 is a fall of snow, or a few days of frosty weather ; the 

 growth of the hair in such instances being dependant 

 on the temperature of the atmosphere. 



The mo*Lie of birds is another preparation for win- 

 ter, which i* analogous to the casting of the hair in 

 quadruped*. During summer, the feathers of bird* 

 are exposed to many accident*. Some of them are torn 

 off during their amorous quarrels ; others are broken or 

 damaged ; while in many species they are pulled from 

 their bodies to line their nests. Previous to winter, 

 however, and immediately after the process of incuba- 

 tion and rearing of the young is finished, the old fea- 

 thers are pushed off by the new ones, and in this man- 

 ner the whole plumage of the bird i renewed. During 

 thi* process of moulting, the bird seems much enfeebled; 

 and, if previously in a weak state, i* in danger of dy- 

 ing during the process. In consequence of this com- 

 plete renewal of the feathers, the winter covering is 

 rendered perfect, and the birds prepared for withstand- 

 ing all the rigour* of the season. 



MIC COLOUR or THE I LOTIIING. The 



difference in point of colour between the summer and 

 winter dress of animals is very conspicuously displayed 

 both among the quadruped* and bird*. We are not 

 ware that it has been ubeeifed among the cul J-blood- 

 ed animate. 



A nxing quadrupeds, the Alpine bare f /.TOM verteetlw) 

 is a very remarkable example. It i* found, in this coun- 

 i the high mountains of the Grampian range. Its 

 wr dress is of a 



MUBmrr dr 



i tawny grey colour; but, about the 



month ofSeptember, it* fur gradually change* toamowy 

 whitenes*. It continue* hi this cute during the win. 

 tcr. and rejm it. plainer covering again i.. Ihr month 

 of April or May, according to tfaa> season. The 



is another of our native quadrupeds which exhibit* in 

 it* drens timiUr change* of colour aooordmg to the sea- 

 son. It frequenuthe ontekart* of wood* and thickets. 

 During the summer months its hair is of a pale reddish 

 brown colour; in harvest it becomet clouded with |lr 



the month of November, with . 

 of a snow whit* colour. Its njsjtsB dress famishes the 

 valuable fur called ermine. Early in spring, the white 



freckled with brown, and in the month of May 

 it completely resume* it* summer garb. 



Among the feathered tribes each imtances of change 

 of colour in the 

 They greatly p 

 the means of 



Ml 



into the system *everal spu- 



The white grous or ptarmigan (7V<rao 

 ay be produced as a familiar example of this 

 kind of hibernation. This bird, like the Alpine hare. 

 inhabit* the higher Grampians, and i* never found at 

 a great distance from the limit* of the snow. In sum- 

 mer its plumage i* of an ash colour, mottled with small 

 dnky spots and ban. At the appieeth of winter the 

 dark colour* disappear, ami ks withers arc then found 

 . white. In remarkably mild winters the 

 i incomplete, a few dusky pot* of 



the summer dress remaining. In spring its winter garb 

 becomes again mottled, and the bin! lo^os much of its 

 beauty. Even the young birds in their first dress re- 

 semble their parents in their mottled plumage, and like 

 them become white at the approach of winter. 



Among the aquatic birds similar changes in the co- 

 lour of the plumage have been observed. The black Guillemots, 

 guillemot (i'rui grylie), so common on our coasts, is of 

 a sooty black colour during the summer, with a white 

 patch on the wings. During winter, however, the 

 black colour disappears, and its plumage is then cloud- 

 ed with ash-coloured spots on a white ground. In the 

 winter drt-s it has been described by some as a distinct 

 species, under the name of the spoiled guillemot. In 

 the more northern regions, as in Greenland, for exam- 

 ple, this bird, in winter, becomes of a pure white co- 

 lour. This is a decided proof of the influence of tem- 

 perature in producing this change of colour. There is 

 a fine example of thU bird in its white winter dress in 

 the collection of the Dublin S,>ciYty, where we saw it a 

 few months ago. It was brought from Greenland by 

 that intelligent and enterprising naturalist Sir Charles 



These change* of colour, which we have already Little ul. 

 mentioned, extend throughout the whole plumage of 

 the bin! ; but in other instances, the change extends to 

 only a small put of the plumage. Thus the little auk 

 (Mem aUt) during summer has it* cheeks and throat of 

 a black colour, but in winter these part* Income dirty- 

 white. In this it* winter gnrb, it i often ^hot on our 

 coasts. It* summer dress i,.dmvd I'ennant to consider 

 it a* a variety, ami a* such to figure it. The black 

 heeded gull (Ijuru* ruUlmadttt), has a black head 

 ' summer, as it* trivial i.ngli-h name intimates. 

 the winter, however, the black colour on the 

 i ; and whin in this dress, it has been 

 regarded by many a* a distinct sperit -', uiultr the name 



In many other bird* there is a remarkable difference 

 in point of colour between the summer and the w inter 

 plumage, although not so striking a* those which we 

 have noticed. The colours of the sumir ^ are 



rich and \ivid ; those of the winter obscure and dull. 

 This is well illustrated in the Dunlin (Trmga nlpina), Dunlin. 

 whose summer plumage has much black and rufous co- 

 lour, but whose winter plumage is dull and cinereous. 

 In its winter dress it has been described as a distinct 

 species, under the trivial name of T. dnclus, or I'urrr. 

 Similar instance* might be produced in the case uf tin- 

 Wagtails, Linnets, and Plovers, and a great many other 

 I. ,,i.. 



From the preceding statements we are naturally led Made of the 

 inquire, in what manner these changes in t' 



of the dress are produced r 



the colour <**" * 

 It has been supposed by 



some, that those quadrupeds which, like the alpine 

 bare end ermine, become white in winter, cast their 

 twice in the course of the year; at harvest when ' 

 they part with their summer dress, and in spring when 

 they throw off tiieir winter fur. Thii opinion dor* nut 

 appear to be supported by any direct observations, nor 

 U it countenance <1 by any analogical reasonings. If we 

 attend to the mode in which the Inir on the human head 

 becomes grey as we advance in year*, it will not be 

 difficult to perceive, that the change is not produced by 

 the growth of new hair of a white colour, but by a 

 change in the colour of the old hair. I Irnce there will 

 be found some hair* pale towards the middle, and white 

 toward* the extremity, while (he ha-e i of a dark colour. 

 Now, in ordinary case*, the hair of the human 



