412 University of California Publications in Zoology [VOL. 11 



western meadowlark consumes something like five ounces (155.5 

 grams) of food during the time it remains in the nest. This 

 weight in grasshoppers would mean 311 individuals and in cut- 

 worms 415 individuals. 



The time of digestion of the western meadowlark was deter- 

 mined by feeding captive juvenile birds and examining the con- 

 dition of the food at intervals after feeding. The following 

 table gives a summary of the results of these experiments : 



TABULAR EESULTS OF EXPERIMENTS ON THE TIME OF DIGESTION 



Time 



Time between 



Exper- without feeding and Food given Condition of food 



iment food killing on examination 



1 3% hrs. 2 hrs. 4 large grasshoppers Finely comminuted 



(Camnula pellucida) and largely digested 



12 small grasshoppers 

 1 robber fly 

 1 beetle (Coniontis sp.) 

 5 ants 



2 5% 3% 20 grasshoppers About one-quarter of 



(Camnula pellucida) volume remained; all 

 10 ants soft parts digested 



3 3^ 2 30 kernels wheat 15 kernels left 



undigested; hulls 

 still undigested 



4 3% 2 1 May beetle Only hard parts 



(Ligyrus gib~bosus} left in stomach 



1 weevil (Bhygopsis sp.) (heads, wing-covers 

 12 grasshoppers knee joints, etc.) 



(Camnula pellucida) 



5 4 5? 28 grasshoppers Stomach empty 



From these data it can be safely concluded that insects are 

 digested in two to four hours and that the stomach is completely 

 emptied every four hours. Beetles and ants, owing to the chi- 

 tinous parts, remain longer in the stomach than do grasshoppers. 

 Cutworms doubtless are digested much more rapidly. Grain is 

 more difficult to digest than insects and remains in the stomach 

 longer (four to five hours). 



These results compare very favorably with the results of 

 similar experiments by other investigators. Experiments carried 

 on by Treadwell (1859), Forbush (1907), and Weed and Dear- 

 born (1903) have demonstrated that birds have a very rapid 



