300 ZOOLOGY 



There are exceptions to the above general rule, as is seen by the 

 fact that locust-catching starlings breed in large numbers in local- 

 ities where locusts have deposited their eggs. At seasons when 

 the number of locusts hatched are few, many starlings die from 

 lack of food. 



Not only do birds aid man in his battles with destructive insects, 

 but seed-eating birds eat the seeds of weeds. This fact alone is 

 sufficient to make birds of vast economic importance. 



Not all birds are insect feeders. Some, as the cormorants, 

 ospreys, gulls, and terns, are active fishers. Sea birds also live 

 upon shellfish, and crustaceans (as small crabs, shrimps, etc.); 

 some even eat organisms of a lower grade of life. The kea parrot 

 takes its meal from the muscles forming the backs of living sheep, 

 while other birds of prey eat living mammals, sometimes of con- 

 siderable size. 



Extermination of our Native Birds. — Within our own times we 

 have witnessed the almost total extermination of some species of 

 our native birds. The American passenger pigeon, once very 

 abundant in the middle west, is now practically extinct. Audu- 

 bon, the greatest of all American bird lovers, gives a graphic 

 account of the migration of a flock of these birds. So numerous 

 were they that when the flock rose in the air the sun was darkened, 

 and at night the weight of the roosting birds broke down large 

 branches of the trees in which they rested. To-day hardly a single 

 specimen of this pigeon can be found. Wholesale killing for 

 plumage, eggs, and food, and alas, often for mere sport, has caused 

 the decrease of our common song birds to a small percentage of their 

 former number within the past fifteen years. Every crusade 

 against indiscriminate killing of our native birds should be wel- 

 comed by all thinking Americans. Without the birds the farmer 

 would have a hopeless fight against insect pests. The effect of 

 killing native birds is now well seen in Italy and Japan, where 

 insects are increasing yearly and do greater damage each year to 

 crops and trees. 



Of the eight hundred or more species of birds in the United 

 States only two species of hawks, the great horned owl, the cow- 

 bird, and the English sparrow may be considered as enemies of man. 



