376 



BIRDS OF PENNSYLVANIA. 



pers and potato beetles, or even cut-worms and " white grubs." It is true they may 

 not know the scientific names of the particular species of grasshoppers or grub noted, 

 but the observation, though less valuable on this account, is still of definite worth. 

 A lew observers have examined stomachs of crows occasionally, and their testimony 

 in regard to the insects found therein therefore possess unusual value, but the 

 larger number by far base their statements entirely on field observations. 



A few farmers contend that the crow rarely or never eats insects of any kind, 

 while others simply state that they have never seen it do so, and express a favorable 

 or unfavorable opinion as to the probability of such a habit. These, however, are 

 individual exceptions, the great majority of observers stating emphatically that the 

 crow does eat insects, and that he eats many; in fact, the unanimity of opinion 

 on this point is rather surprising, and much of the most favorable testimony comes 

 from men who are most severe on the crow as regards its other habits. 



In this connection, the evidence furnished by the stomachs examined in the divi- 

 sion during the past year is interesting. The insects contained in these stomachs 

 have been submitted to the entomologist of the department, and a summary of the 

 results of his examination will be found in another place ; but while examining the 

 other components of the food it was easy to separate the insect material from the rest, 

 and to estimate the proportion which it formed of the entire food. 



The following table, showing the amount of insect food in the stomachs examined, 

 contains several points of interest : 



Table showing the amount of insect food in the stomachs of eighty-six crows (Corvus 

 americanus), arranged by months : 



It appears from the above table that sixty-three of the eighty-six stomachs ot the 

 Common Crow which were examined, or more than seventy-three per cent., con- 

 tained some insect food, the average amount in each of the sixty-three stomachs 

 being nearly twenty per cent., or one-fifth of the entire food. Fourteen and one- 

 half per cent, of all the food contained in the whole eighty-six stomachs consisted of 

 insects, and this in spite of the fact that two-thirds of these stomachs were from birds 

 taken during the colder half of the year, namely, between October 1 and April 1. 



At first sight it seems still more remarkable that ninety per cent, of the stomachs 

 taken in December contained some insect food, while but eighty-seven and one-half 

 per cent of those taken in July contained insects. Those taken in July, however, 

 contained in the aggregate more than five times as much food of this kind as those 

 taken in December. 



Again, of the fourteen stomachs taken in January, but four contained insect re- 

 mains, as against eighteen out of twenty taken in December. By consulting the 

 detailed results of the examination, however, the reason is evident ; for ten of the 

 January birds were taken at East Hartford, Conn., when the ground was mostly 

 covered with snow, while most of the December birds were taken near Washington, 

 D. C., when the ground was mostly bare. 



