90 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. 



introduced about 1880 and rapidly extermitiated the rabbits, which 

 had been in possession of the island for half a century. In one of the 

 harbors of Kerguelen Island, southeast of the Cape of Good Hope, cats 

 were allowed to run wild upon a little islet known as Cat Island, which 

 has been used as a wintering place for sealers for many years. Here 

 they live in holes in the gi-ound, preying upon sea birds and their 

 young, and are said to have developed such extraordinary ferocity 

 that it is almost impossible to tame them even when captured young. 

 Dr.W. L. Abbott states that on Aldabra, about 200 miles northwest of 

 Madagascar, cats are common on the main island, and have com- 

 pletely exterminated the flightless rail {Rougetius aldabraniis), an 

 interesting bird, peculiar to this group of islands. They are also 

 numerous on Glorioso Island, 120 miles to the southeast, and in con- 

 sequence birds are less common even than on Aldabra.^ 



The Chatham Islands, 500 miles east of New Zealand, were 

 colonized about fifty years ago; cats, dogs, and pigs were introduced, 

 and the native birds, rejDresented by fifty-five species, including 

 thirteen not found elsewhere, have since greatly decreased in num- 

 bers. Two of the most interesting birds are land rails of the genus 

 Ccibalus. Dr. Dieffenbach, naturalist of the New Zealand Company, 

 who visited the islands in 181:0, states that one of these rails {Cabalus 

 dieffenhachi), called by the natives "meriki," was formerly com- 

 mon, but since the introduction of cats and dogs- it has become very 

 scarce. It is now probably extinct, and the closely related species 

 C. modesius will doubtless soon suffer a similar fate, since the islet of 

 Mangare, to which it is confined, has recently been invaded by cats.^ 



SOURCES OF DANGER FROM NOXIOUS SPECIES. 



The animals and birds which have thus far become most trouble- 

 some when introduced into foreign lands are nearly all natives of 

 the Old World. The mammals belong to three. orders: (1) Rodents, 

 including rats of two or three species, the house mouse, and rabbit 

 of western Asia or southern Europe; (2) Carnivores, represented by 

 the stoat, weasel, and common house cat of Euroj)e, and the mon- 

 goose of India; (3) Cheiroi)tera, represented by large fruit-eating bats 

 or flying foxes of Australia and the Malay Archipelago. Fljing foxes 

 have not yet been actually introduced, but are likely to be carried to 

 different islands in the Pacific, and are dangerous because of their 

 depredations on fruit. The birds comprise the house sparrow and 

 starling of Europe, and the mina of India. Other species, usually 

 regarded as beneficial in their native homes, such as the European 

 skylark, green linnet, black tlirush or blackbird, and the great tit- 

 mouse or kohlmeise, are likely to prove injurious in new surround- 

 ings. Most of these species have extended their range from the east 



' Proc. U. S. Nat. Mus. , XVI, 1894. pp. 762, 704. 

 ■^Forbes, Ibis, 6th ser., V, 1893, pp. 523, 531-533. 



