238 BULLi-TIN 191, UNITED STATES NATIONAL MUSEUM 



hoppers. Caterpillars, always a favorite source of food for nestling 

 birds, were present in more than a third of the 778 nestling crow 

 stomachs examined. 



The insect food of the crow is one of the strongest points in its favor 

 and should be given proper consideration in judging the economic 

 status of the species. The crow is an enemy of gypsy and browntail 

 moths, but it has been observed that new colonies of moths often form 

 about the nests of crows, indicating that these birds may serve as an 

 agent in the spread of these pests. 



Unfortunately the food of the crow is by no means restricted to 

 insects, and among the bird's less admirable traits is its destruction of 

 eggs and young of other species of birds, a habit that has placed the 

 crow on the black list of many both sportsmen and bird lovers. How- 

 ever, these depredations, in many instances, have been greatly and per- 

 haps willfully exaggerated in articles advocating the destruction of the 

 crow, which have appeared in many sporting columns of newspapers and 

 magazines. The examinations by the U. S. Biological Survey reveal 

 that only about a third of 1 percent of the animal food of the adults and 

 1.5 per cent of the food of nestlings is derived from wild birds and their 

 eggs, and only about one in every 28 crows and one in every 1 1 nestlings 

 had eaten such food. 



The percentage of such food, as would be expected, runs higher in 

 crows that inhabit the proximity of nesting waterfowl. Examinations of 

 adult crows collected in such situations in the prairie provinces of Canada 

 show that they had eaten four times the quantity of other birds and 

 their eggs, and the young six times the quantity eaten by crows collected 

 in the United States. On the basis of frequency of such predation in 

 Canada the adult crow is ten times and the nestling crow six times as bad 

 as their fellows in the United States. This pronounced record of bird 

 and egg destruction in Canada was due primarily to the fact that the 

 birds collected were taken in close proximity to nesting waterfowl, 

 almost to the exclusion of any obtained in agricultural sections. 



Observations on the I^wer Souris Refuge in North Dakota in 1936 

 and 1937 showed that the crow is not an outstanding hazard to water- 

 fowl there. Only 1.7 percent of the 351 nests studied in 1936 were 

 destroyed by crows, while in 1937 the birds preyed upon 3.4 percent of 

 the 566 nests under observation. Even with the latter rate of loss, the 

 crow on this refuge is at present considered to be a minor hazard to 

 waterfowl. 



Many independent observers have reported the destruction of eggs and 

 young of both game and song birds, and there is no doubt that the crow 

 at times is guilty of serious depredations. Baker (1940) reports the 



