12 BULLETIN 621, TJ. S. DEPARTMENT OE AGRICULTURE. 



cent). In the three months following a very uniform decrease is 

 noted (46.98, 44.28, and 39.40), but even as late as September the 

 animal portion constitutes nearly a third (32.32 per cent) of the 

 food. Lower percentages from October to March, inclusive (14.29', 

 18.74, 13.18, 14.94, 10.97, and 16.05), reflect the struggle for existence 

 which is the lot of the crow during the colder months. With April, 

 however, comes relief, and the animal food again becomes conspicuous 

 (34.09 per cent). 



INSECTS. 



In passing judgment on the economic value of most birds, nothing 

 is of greater importance than a thorough understanding of their in- 

 sect food. By this it is not meant merely that one should know the 

 noxious forms eaten, the destruction of which is a benefit to man, but 

 cognizance must also be taken of the complex relations between the 

 various beneficial (predacious and parasitic) insects destroyed and 

 the injurious ones upon which the bird commonly feeds. Some of 

 this information is as yet unavailable, owing to the lack of knowledge 

 of the interrelations between insect forms. Enough has been learned 

 of the crow, however, by examination of 2,118 stomachs, 1,340 of 

 which were of adults, and by reliable field observations to make 

 possible the assertion that, for all practical purposes, sound judg- 

 ment on the merits of the insect-feeding habits of the crow can be 

 given. The series of stomachs available is sufficiently large and was 

 collected under the varying environments of so many localities that 

 the results obtained are probably close to a true average for the area 

 in which the crow is common. 



Insect food was taken by adult crows in every month of the year, 

 though in January it amounted to only 1.29 per cent. February was 

 represented by 4.85 per cent ; March, 4.58 ; April, 14.72 ; May, 39.77 ; 

 June, 35.95 ; July, 33.85 ; August, 35.07 ; September, 27.64 ; October, 

 11.51; November, 14.16; and December, 4.49. The insects identified 

 belong to 12 orders, embracing no less than 455 specifically distinct 

 forms. A discussion of this part of the crow's food will be taken up, 

 order by order — Coleoptera (beetles), the order best represented in 

 the crow's diet (7.58 per cent of the yearly food), being treated first. 



Coleoptera (beetles). 



The crow is primarily a terrestrial feeder. Its quota of beetles, 

 therefore, is made up almost exclusively of species found on or near 

 the ground, or those which, by the turning over of sticks, clods of 

 earth, or dung, are secured from beneath the surface. The latter 

 is a common method of feeding employed diligently by the crow 

 from early spring to the beginning of autumn, when the usual crop 

 of grasshoppers furnishes a more accessible supply of food. 



