128 SPARROW IN UNITED STATES. [CH. Ill 



The country inhabited by an animal is not neces- 

 sarily the only one in which it can flourish. 



The view that animals are suited to the countries 

 which they inhabit and to no others, that in fact their 

 distribution is a matter of temperature, is proved to be 

 quite untenable by the phenomena of colonisation. Sir 

 Charles Lyell 1 refers to the case of the Ligurian bee, Apis 

 mellifica, which is a native of Europe. It was however 

 introduced by the early settlers into America and has 

 since that time prospered exceedingly on its own account, 

 apart altogether from the protection afforded by man to 

 his own hives. It inhabits the forests of the interior and 

 builds its combs in hollow trees. 



The most striking instance however of successful in- 

 vasion of a new country by foreign colonists is offered by 

 the sparrow. This bird is now as ubiquitous in most 

 parts of the United States as it is in this country. To 

 such an extent has it proved capable of adapting itself to 

 a new soil and somewhat different climate that measures 

 concerted for its destruction by the United States Govern- 

 ment have proved quite incapable of producing any great 

 effect upon its numbers; and yet it is only a few years 

 since it was artificially introduced. 



Perhaps the most striking example among plants of 

 the capacity which an introduced organism sometimes 

 possesses of suiting itself to new circumstances is the 

 common canal and pond weed of this country, the Anacharis, 



1 Principles of Geology. 



