CHAPTEE III. 



INSECT FOOD OF THE CROW. 



The matter of the Crow's utility as an insect destroyer is one of 

 prime importance; in fact, it is the crucial test of the bird's value 

 The material available for the decision of this question consists of the 

 insect contents of 909 stomachs, taken at various places and times, the 

 great majority during the warmer half of the year. 



Most of the older ornithologists recognized the fact that Crows ate 

 insects in considerable numbers, but ignored the fact that many insects 

 are beneficial ; and moreover they took no pains to determine what 

 proportion of the Crow's diet consists of insects. Even at the pres- 

 ent time these points are very generally overlooked, and to the best of 

 our knowledge there is nowhere a record of the carefully identified 

 contents of a dozen Crow stomachs taken in summer. A few nat- 

 uralists have put on record the results of more or less thorough exam-, 

 inations, but in too many cases we find only such general statements 

 as 6 contents consisted of seeds, berries, and insects,' or possibly of 

 c grain, carrion, and beetles,' without any attempt to determine the 

 kind or amount of each. 



Eight hundred and one out of 909 stomachs examined contained 

 insect remains in quantities varying from the merest trace to 100 per 

 cent. The following table shows the number of Crow stomachs col- 

 lected during each month, the numbers which contained insect remains, 

 and the average percentage of such remains for the whole number of 

 stomachs in each month : 



Table showing average percentages of insect material contained in 909 Crow stomachs, 



arranged by months. 



Month. 





Number 



Percentage 





containing 



of insect 





insects. 



contents. 



53 



21 



2.2 



23 



10 



3.3 



26 



16 



5.8 



42 



36 



49.2 



364 



357 



47.1 



165 



157 



40 



45 



42 



26.5 



24 



24 



35.6 



44 



40 



24.6 



46 



42 



16.7 



18 



17 



25.8 



59 



39 



4.7 



909 



801 



23.5 



January... 

 February . 



March 



April 



May 



June 



July 



August . . . 

 September 

 October . . . 

 November. 

 December . 



Total 



56 



