34 



vicinity to feed upon the eggs or young of tlie sea fowl. The 

 writer found on this island a nest of the north-western crow, which 

 was built in a hollow dug in the earth at the top of the rock and 

 protected by a few scattered grasses and cacti. This nest con- 

 tained three young crows and was guarded closely by the parents. 

 The only reasonable explanation of the breeding of the crows upon 

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

 that their favorite food, the sea birds' eggs, was more accessible 

 to them here than elsewhere. Being located on the island, they 

 were enabled 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 nest- 

 ing and for securing animal food, with the exception of the sea 

 birds' eggs, than on the rock where the crows bred. Stomach ex- 

 aminations cannot safely be relied upon entirely to determine the 

 amount of eggs or young birds eaten by the crow. The rapidity 

 with which such substances as the contents of eggs are digested by 

 the crow suggests the probability that egg contents cannot often be 

 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 por- 

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

 become so finely disintegrated in the stomach as to be unrecog- 

 nizable. The softer parts of nestling birds would soon disappear 

 from the stomach, and the bones, being soft, are digested. 



According to the stomach examinations made, that portion 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 year would amount to eighteen and one- 

 fourth ounces. Assuming that the young birds or eggs eaten by 

 the crow average one ounce each in weight, which is perhaps a 

 high average, we have eighteen and one-fourth birds or eggs to 

 each crow as its record for the season. If we allow only ten fami- 

 lies of crows of five each for one of our larger western townships, 

 the fifty crows would destroy over nine hundred young birds or 

 eggs. Whether such destruction should be regarded as " trivial," 



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



