3 



relationship to other forms of life, past and present. As a matter of sentiment, all 

 lovers of nature are interested in birds, their b^'auties of form and colour, their 

 intelligence, sociability and musical powers excite both wonder and admiration 

 in the minds of all who give them even casual attention. It is, however, from the 

 economic standpoint, chiefly, that I propose to deal with the subject in this work, 

 and the economic value of our familiar birds will, to some extent, he pointed out 

 in the succeeding pages. 



The economic value of birds to man lies in the service tlie birds render by 

 keeping within proper limits th;? various forms of insects which are injurious to 

 our crops or animals, in preying upon rats, mice, and other destroyers of our grain 

 and fruit trees, in devouring weed seeds, in acting as scavengers, and in the case 

 of game birds and wildfowl furnishing sport and food. 



No reliable estimate has ever been made of the annual loss to the farmers of 

 Ontario by the depredations of insects. In the United States much careful atten- 

 tion has been given to the subject, and in a report of the Department of Agricul- 

 ture at Washington, issued in 1912, Dr. Henshaw estimates the loss to the agri- 

 cultural interests of that country at upwards of $700,000,000. Our losses will cer- 

 tainly be as large proportionately. This loss is caused chiefly by reason of an in- 

 sufficiency of bird life on our cultivated lands; experience the world over has shown 

 that as bird life decreases insects increase; also, that birds are more efficient in 

 keeping down insect pests than are all other agencies, natural and artificial, com- 

 bined. 



Under ordinary conditions the number of birds required to keep plant-eating 

 insects in proper check need not be extraordinarily great, for in order to main- 

 tain their active bodies adult birds require an enormous amount of food in pro- 

 portion to their size and weight, while the quantity consumed by the young in 

 the nest is far greater yet. In the case of nestlings their food supply must neces- 

 sarily be great, for their growth is very rapid; birds like the Sparrows. Warblers, 

 Thrushes, &c., attaining nearly full-size and becoming sufficiently well-fledged to 

 leave the nest in about eleven days from the time they were hatched. 



The powder of flight possessed by birds enables them to act more efficiently as 

 a check upon any abnormal increase of ins cts. o- small animal*, t'mn any other 

 force in nature. Should an unusual abundance of any insect, or of field mice, 

 occur in any locality, birds wliich feed upon them will soon be attracted to the spot, 

 and there they will remain until usual conditions are restored and the plague 

 abated. In other lands this habit of the birds which act as scavengers renders good 

 service in disposing of animal matter wdiich would otherwise decompose and poison 

 both air and water. 



MiGEATION OF BlRDS. 



Ever since men first began to make records of natural phenomena the arrival 

 and departure of migratory birds have arrested attention. The Greek and Roman 

 philosophers remarked it, and the writers of the Old Testament commented 

 upon it. As yet, however, no satisfactory explanation of the origin of the habit of 

 migration has been given. Some modern naturalists think that change of climate 

 such as that which took place during the glacial period affords a rational and cer- 

 tain explanation of the phenomenon. ^\lien examined closely, however, under the 

 light of recent research this theory is open to many objections. At any rate, if the 

 general habit of migration originated by reason of the violent climatic changes 

 which occurred during the glacial period, it has been and is still being so greatly 



