DANGER OF INTRODUCING NOXIOUS ANIMALS AND BIRDS. 89 



that a hunter could shoot fifty in a single day. Dr. Finsch also cites 

 a case mentioned by Ilochstetter in which 25,000 wild pigs were said 

 to liave been killed by three hunters in less than two years. 



Sheep and goats when numerous are likely to cause widespread 

 injury, jiarticularly in forested regions. An instructive exan>ple of 

 tl\e damage done by goats is that on St. Helena, described by Wallace.^ 

 St. Helena is a mountainous island scarcelj' 50 square miles in extent, 

 and its lughest summits reach an elevation of 2,700 feet. At the time 

 of its discovery, about the beginning of the sixteenth century, it is 

 said to have been covered by a dense forest; to-day it is described as 

 a comparativelj' barren rocky desert. This change has been largely 

 l)rought about b,y goats first introduced b.v the Portuguese in 1513, and 

 which multiplied so fast that in seventy-five j'ears they existed by 

 thousands. Browsing on the jxning trees and shruljs, they rapidly 

 Ijrought about the destruction of the vegetation which protected the 

 steej) slopes. With the disappearance of the undergrowth, began the 

 washing of the soil b}- tropical rains and the destruction of the forests. 

 In 1709 the governor reported that the timber was rapidly disappear- 

 ing and that the goats should be destroj'ed if the forests were to be 

 preserved. This advice was not heeded, and only a century later, in 

 1810, another governor reported the total destruction of the forests 

 by the goats, and in conseciuence an expense of 5^13,000 (£2,729) in 

 one year for the importation of fuel for Government use. 



The Santa Barbara Islands, off the coast of southern California, and 

 the island of Guadalupe, off the Lower California coast, are utilized 

 as ranges for goats. All these islands are drj' and more or less covered 

 with Ijrusli, but arborescent vegetation is comparatively scarce. The 

 goats practically run wild, and already exist in considerable numbers. 

 On Santa Catalina, one of the Santa Barbara group, wild-goat hunting 

 is one of the diversions afforded tourists, and is considered one of the 

 principal attractions of this popular summer resort. As j'et the goats 

 have not been on the islands long enough to cause any serious effects 

 on the vegetation, and they maj' never bring about the ruin which has 

 been wrought on St. Helena. But it is scarcely possible for the islands 

 to be grazed by goats for an indefinite length of time without suffering 

 serious damage. 



House cats are often greater pests than commonlj* supposed. 

 When numerous about the suburbs of cities and towns, they are 

 apt to forage for a living either from necessity or choice, and their 

 food is by no means confined to rats and mice. They are constantly 

 on the watch for birds, but it is impossilile even to estimate liow 

 many they destroy. It is certain, however, that in some places the 

 decrease in native birds is largely due to their j)resence. Where 

 cats have run wild on isolated islands, their work can be more readily 

 appreciated. On Sable Island, off the coast of Nova Scotia, they were 



' Island Life, 1880, pp. 283-286. 



