Woodpeckers prospecting Rotlen Trees, 1 4 1 



Whether woodpeckers return to the hollows of decaying 

 trees and become semi-torpid or not, it is a fact which 

 every forest warder who has had his attention directed to the 

 circumstance must have noticed, that no sooner does the 

 severe frost of midwinter set in than the above and other 

 resident woodpeckers suddenly disappear ; whereas, should a 

 sudden thaw take place, they come out again in numbers. 



The two most common woodpeckers are the Hairy and 

 Downy species, which bear a resemblance to the Greater 

 and Lesser Woodpeckers of Europe, but differ in some im- 

 portant characteristics. Individuals from various regions present 

 remarkable discrepancies in size. Thus the hairy woodpecker 

 of Canada is much larger than the same bird of Mexico, which 

 is again smaller than that of the southern and middle States — 

 the extremes being from eight to eleven inches in length. 

 Professor Baird has noticed that birds of wide distribution 

 in latitude,* whether migrant or resident, will be found to 

 be larger the higher the latitude of the place of birth, and that 

 there is a certain variation in size dependent on the extreme 

 northern and southern limits of distribution during the breed- 

 ing season, the more northern individual being the larger, the 

 more southern the smaller. This is precisely what I have 

 noticed with reference to the birds of Europe and Asia. I 

 found the redbreasts, thrushes, blackbirds, etc., of Southern 

 Europe smaller than those of England, and the black partridges 

 and jackals, etc., of the plains of India relatively much smaller 

 than the same animals met with on the temperate regions of 

 the Himalayas. Again, the authority just referred to states 

 that the black and hairy woodpeckers, although neither are 

 migratory, both have a wide distribution in latitude, and that 

 there is a very great difference in size — for example, between 

 specimens from Florida and Canada ; and these laws he found 



* This authority records the same in connection with the belted king- 

 fisher, a species common to the entire continent, there being a remark- 

 able difference in the size of specimens from the Atlantic and Pacific 

 shores, the eastern being the smaller. — Am. Journal of Science, vol. xli. 



