VALUE OF BIRDS TO MAN. 51 



came from the insects fed to it not more than thirty-three 

 minutes before it was killed. 



In summing up the results, Mr. Kirkland says : "I think, 

 from what we have seen, that we might expect to find the 

 gizzard empty in from one to one and one-half hours." 



Such an experiment should be carried farther, but enough 

 was learned to show that the stomach of a young Crow prob- 

 aljly can be filled Avitli food and emptied of the digested 

 material from eight to twelve times a day during the long 

 days of midsummer, when their appetites are at their best. 



Digestion in some of the smaller birds is doubtless even 

 more rapid, for they are enabled to dispose of a still larger 

 amount of food in proportion to their size. Mr. Owen in- 

 forms us that the time required for a blueberry to traverse 

 the digestive tract of his Hermit Thrush ^vas practically an 

 hour and a half. Mr. C. J. Maynard once told me that in 

 a similar experiment a Cedar Bird passed the residue of food 

 within thirty minutes after the food was taken. Weed and 

 Dearborn found that a blackberry was digested by a young 

 Cedar Bird in half an hour. 



The Number of Insects eaten by Young Birds in the Nest. 



The remarkable appetites of young birds keep their de- 

 voted parents very busy supplying food most of the time 

 from morning till night. The mother bird spends practically 

 all her time either in searching for food, brooding, protect- 

 ing, and feeding the young, or cleaning the nest (for all the 

 smaller birds that nest openly are obliged to dispose of the 

 excreta of their young, that it may neither befoul the nest 

 nor betray its location to their enemies). Most of the visits 

 made by the old birds to the nest during the day are for the 

 dual purpose of feeding the young and keeping the nest 

 clean. Records kept of the number of these visits show 

 the industry of the parent birds and the food capacity of 

 the young. 



My assistant, Mr. F. H. Mosher, watched a pair of Red- 

 eyed Vireos feeding their young on June 13, 1899. There 

 were three nestlings, about one day old. At this early age 

 the young of most small birds are fed mainly by regur- 



