288 BOARD OF AGRICULTURE. [Pub. Doc. 



top of the rock, and protected only by a few scattered 

 grasses and cacti. This nest contained three young crows 

 and was guarded closely by the parents. The only reason- 

 able explanation of the l)reeding of the crows upon the 

 earth upon the top of this barren, rocky island seemed to 

 l)e that their favorite food, the sea birds' eggs, was more 

 accessible to them there than elsewhere. Beino- located on 

 the island, they were enal)led to reach the nests of the sea 

 birds far in advance of other crows, which must come from 

 other islands situated a mile or more away. On these other 

 islands there was a great forest growth ; vegetation was far 

 more plentiful, there were bars bare at low tide, and there 

 was in every way a better opportunity for nesting and for se- 

 curing animal food, with the exception of the sea birds' eggs, 

 than on the rock where the crows bred. Stomach examina- 

 tions cannot safely be relied upon entirely to determine the 

 amoiuit of eggs or young l)irds eaten by the crow. The 

 ra})idity with which such sul^stances as the contents of eggs 

 arc digested by the crow suggests the probability that egg 

 contents cannot often l)e recognized in the birds' stomachs. 

 Indeed, Professor Barrows reports that the remains of eggs 

 found in the stomachs of young birds consisted only of 

 pieces of shell.* As the crow usually makes but one hole 

 in the shell and sucks or eats out the contents, it is not 

 likely to swallow much of the shell, and such small portions 

 of the shells of the eggs of small birds as are swallowed 

 soon become so finely disintegrated in the stomach as to be 

 unrecognizable. f The softer parts of nestling birds, when 

 eaten by the crow, would soon disappear from the stomach, 

 and the bones, being soft, are digested. 



According to the stomach examinations made, that por- 

 tion of the food consisting of the eggs and young of wild 

 birds forms hardly one per cent of the food of the crow for 

 the year. Now, if we assume that the crow eats only five 

 ounces per day, or one-half the amount required by our 

 young birds, one per cent of the food of the crow for the 



* "The Common Crow of the United States," page 47. 



t It is but just to say that Professor Beal informs me that from his observations 

 and dissections he has been led to Ijelieve that the crow usually swallows some egg- 

 shell when eating or sucking eggs, and also that pieces of dry egg-shell are frequently 

 swallowed by the crow. 



y 



