58 



Services of Hawks end Ozvls to Man. 



tailed examination of these and four others 

 gave the following results: 



Sex. 



Species. 



Stomach Contents. 



i ad. 



B. 



boreal is... 



1 Pine Mouse (Arvicola pinatorum). 



i ad. 



B. 



borealis. . . 



2 Meadow Mice (A. ripariusV 



■9 ad. 



B 



borealis... 



A. liparius and Hesperomys leucopus. 



'$ ad. 



B. 



borealis. . . 



2 Mus musculus, Arvicola and Hesp. 



i ad. 



B. 



borealis.. . 



I Snrew (Sorex', 2 M. muse, and Arvi. 



« ad. 



B 



borealis... 



2 A. riparius. 



i ad. 



B. 



borealis.. . 



I Sorex, 2 -A., riparius. 



S ira. 



B 



borealis.. . 



3 A. riparius. 



Stomach entirely empty. 



i ad. 



B. 



borealis.. . 



i im. 



B. 



borealis.. . 



3 Meadow Mice (A. riparius). 



i ad. 



B 



lineatus. . . 



2 M. musculus, I Hesper. and Arvi. 



i im. 



B. 



lineatus. . . 



I House Mouse (M. musculus). 



S im. 



A 



cooperi. .. 



Remains of Quaii (C. virginianus). 



A more careful examination, which will be made later, will 

 probably increase the total number of mice by half a dozen. 



Fifty thousand dollars a year paid by one 

 State for the destruction of birds that sub- 

 sist almost wholly on mice, beetles and 

 grasshoppers ! There is no disputing the 

 facts, and the Pennsylvania Agricultural 

 Societies are trying to balance the account 

 with very grave misgivings as to how it will 

 turn out. 



This examination of the stomach contents 

 of seventy-four Pennsylvanian and fourteen 

 Maryland birds, in only three of which were 

 there any remains of chicken, leads to the 

 inference that 2^ per cent, of their food is 

 chicken. Averages based on such limited 

 material are of course liable to error, but 

 we must draw our conclusions from the 

 facts that we have. 



On the average taken it may be calculated 

 that of the 50,000 birds killed in Pennsyl- 

 vania last year, 2)^ per cent., or 1,250 

 birds, fed on chicken all the year round, 

 eating an average of say 200 lbs. of chicken 

 each bird within the year; this would 

 give a total consumption of 250,000 lbs. of 

 chicken, quite enough to anger the good 

 wives who lo.st them, and representing a 

 money value of about $25,000. 



But there is another side of the story 

 Nirtety-.seven and a half per cent, of them 

 are found to subsist on mice and other 

 small rodents, small birds and insects, but 

 principally on mice. Of 50,000 birds killed 



we may assume that 40,000 lived on mice 

 and other small rodents, consuming let us 

 say only 100 lbs. each in the year. These 

 figures give us 4,000,000 lbs. weight of mice, 

 say 40,000,000 individuals, as the number 

 which escape death through the destruction 

 of the hawks in one year. When we remember 

 that mice are more destructive to the farmer 

 than birds, and that they multiply much more 

 rapidly, we can begin to estimate what 

 would be the consequences of the extermi- 

 nation of hawks and owls throughout the 

 country. The more we strive to picture the 

 consequences, the more appalling is the 

 prospect. 



The mice would have to be kept down at 

 any cost, even though the whole resources 

 of the nation were taxed in the effort, but 

 how much simpler and wiser were it to leave 

 the task to the incessant vigilance of nature's 

 agents, the hawks and owls, which execute 

 it so effectively and so silently, that we 

 never suspect how important is the work 

 they are doing — never realize that they 

 stand between us and inestimable calamities, 

 until it is too late, until their extinction ex- 

 poses our fields to the ravages of insidious 

 foes, hitherto held in check by these faith- 

 ful wardens. 



The occasional tax levied on the farmer's 

 chickens is very inconsiderable in compari- 

 son with the service rendered. The loss in 

 chicken can be estimated accurately, the 

 value of the service rendered is simply in- 

 estimable. It is not simply a calculation of 

 what 40,000,000 mice will eat in a year, but 

 what would be the destructive capacities of 

 the progeny of 40,000,000 mice in three, five 

 or seven years, if the hawks were all destroy- 

 ed, and man were left unaided tcv impose 

 such restraints as he could upon the natural 

 tendency of mice to increase up to the 

 limits of their means of subsistence. 



Perhaps it would be well to encourage 

 the extinction of the hawks and owls in 

 Pennsylvania ; the experience gained would 

 be of inestimable value to the other States. 



