DANGER OF INTRODUCING NOXIOUS ANIMALS AND BIRDS. 109 



already in the coloiij^ to be cc iifined in hutches or boxes constructed 

 according to certain prescribed regulations, and authorized anyone to 

 destroy rabbits found on his premises, on Crown lands, or along jjub- 

 lic roads. Western Australia, profit ing l)y the experience of her sister 

 colonies on the eastern side of the continent, has taken measures to 

 secure pi'otection from the evils of indiscriminate and ill-advised accli- 

 matization bj^ the passage of the so-called "Destructive birds and 

 animals act" (57 Vic, No. 22). This law, passed in 1893, prohibits the 

 introduction of all birds or animals which, in the opinion (»f the 

 governor-in-council, are destructive to vineyards, orchards, fruit trees, 

 or any agricultui-al produce. The act also prohil^its the keeping of 

 such birds or animals on private premises, authorizes the desti'ucTion 

 of those already in the colony, prohibits the liberation of any destruc- 

 tive bird or animal, and permits duly authorized officers to enter prem- 

 ises for the purpose of seizing or destroying such birds or animals. 

 The term "destructive" is interpreted to mean any species to which 

 the governor-in-council may from time to time extend the provisions 

 of the act by proclamation, and the selection of species is based mainly 

 upon the recommendations of the bureau of agriculture.^ The law is 

 therefore elastic and may be easilj^ modified when necessary. Spar- 

 rows and rabbits were originally included in 1893, flying foxes were 

 added in December, 1895, and starlings, blackbirds, and thrushes in 

 January, 1896. 



SUMMARY. 



(1) Acclimatization of plants differs from that of animals since 

 plants are introduced for cultivation and thus kept to a certain extent 

 within control, ^^liile animals are liberated and controlled only by 

 natural enemies or unfavorable conditions. 



(2) Animals and birds are distributed from one continent to another, 

 and to islands, either by accidental means or by the direct agencj' of 

 man. Most animals are intentionally introduced into new regions, 

 cases of accidental dispersion being comparatively rare excei)t among 

 rats and mice. 



(3) Domesticated animals, like plants, may run wild and l)eeome 

 Injurious, especiallj^ in regions where food is abundant and natural 

 enemies are absent. Goats and cats on isolated islands are well- 

 known examples. 



(4) The animals and birds which have thus far proved most inju- 

 rious are the rabbit, mongoose, stoat, weasel, flying fox, English 

 sparrow, starling, and mina. The skylark, green linnet, black thrush, 

 and great titmouse, or kohlmeise, are of doubtful value and likely to 

 prove injurious. These species are all natives of th^ Old World, and 

 with the exception of the mongoose, mina, and flying foxes, are inhab- 

 itants of the temperate regions of Europe and western Asia. 



' See Journ. Bureau Agr. Western Australia, II, December 10, 1895, pp. 630-631; 

 III, 1896, p. 676. 



19007 3 



