FORMS INJURIOUS TO HUMAN INDUSTRIES 



347 



protected by the vegetation to which it in great part owed its 

 origin. When this was destroyed, the heavy tropical rains soon 

 washed away the soil, and has left a vast expanse of bare rock 

 or sterile clay. This irreparable destruction was caused in the 

 first place by goats, which were introduced by the Portuguese 

 in 1 5 13, and increased so rapidly that in 1588 they existed in 

 thousands. These animals are the greatest of all foes to trees, 

 because they eat off the young seedlings, and thus prevent the 

 natural restoration of the forest. They were, however, aided by 

 the reckless waste of man." 



Rats, Mice (fig. 1242), and other small 

 rodents are destructive to stored o-rain 



o 



and other commodities, and may become 

 a thorough nuisance in dwellings, as most 

 of us have found by experience. Such 

 creatures may also be productive of serious 

 harm by disseminating various diseases. 

 Rats, for example, often cause trichinosis 

 in swine (see p. 344), and hence indirectly 

 in human beings, or may spread such viru- 

 lent germs as those of bubonic plague. 



Injurious Birds (Aves). — Large birds 

 of prey, such as Eagles, may attack various 

 domesticated animals, and even the Raven 

 {Cornjus corax) is known to injure lambs, 

 among other forms. The Kea Parrot 

 {Nestor notabilis) of New Zealand has 

 acquired the reprehensible habit of killing sheep by biting deep 

 holes in their backs, its object being said to be to reach the fat 

 in the neighbourhood of the kidneys. The smaller Birds of Prey 

 may raid poultry-yards or game-preserves, and some of them 

 destroy useful insectivorous birds. Certain species, however, do 

 more good than harm (see p. 327). 



Among insectivorous birds the Woodpeckers damage trees in 

 the course of their search for food (fig. 1 243), and also sometimes 

 by excavating nesting-holes in sound trunks. A great many 

 plant-eating or omnivorous birds do much mischief in cultivated 

 fields, gardens, and orchards, the exact nature of the depredations 

 depending upon the species. Most, if not all, omnivorous birds 

 also do a certain amount of good, sufficient, in some cases, en- 



T243. — Tree " ringed " by 

 Woodpecker 



