CALIFORNIA SHRIKE. 35 



A shrike of the eastern subspecies was kept in confinement for some 

 weeks by the Biological Survey and notes made in regard to its food 

 habits. A thorny bush was placed in the cage, and whenever the 

 bird was given food in excess of its immediate wants it impaled the 

 surplus upon a thorn, taking great pains to press it securely down. 

 On one occasion a dead mouse Was placed in the cage ; it was at once 

 seized and forced into the fork of the bush and was then torn piece- 

 meal and eaten. Note was taken of the time when the last bit was 

 swallowed, and a close watch kept for further results. In an hour 

 and a half the bones and hair of the mouse were disgorged in the form 

 of a neat pellet. Everything digestible had been stripped from the 

 bones. A May-beetle (Lachnosterna) was eaten and the pellet con- 

 taining the remains appeared in an hour and twenty minutes. At 

 another time a ground beetle (Calosoma) and a stink bug (Nezara) 

 were eaten and their remains appeared in forty minutes. As both 

 of the insects are nauseous, at least to human smell and taste, it 

 is possible that they may have been unacceptable to the stomach of 

 the bird, and so were rejected before digestion was complete. On 

 another occasion a second Calosoma and a moth were given, and their 

 remains were regurgitated in an hour and fifteen minutes. These 

 experiments show how rapid is the process of avian digestion. 



In the investigation of the food of the California shrike 124 stom- 

 achs were examined. They were collected in every month, but the 

 greater number were taken in the warmer months. 



Vegetable food. — Animal food of all kinds amounts to 97.5 percent, 

 or so nearly the whole that it is fair to suppose that the greater 

 part of the 2.5 percent of vegetable matter present was swallowed 

 unintentionally — that is, when sticking to something else. All of it 

 was contained in 9 stomachs. Fruit appeared in 2 stomachs, seeds in 

 2, and rubbish in 6. Of these probably only the fruit was taken as* 

 food. One stomach was filled with elderberries to the amount of 84 

 percent of the contents, the other, with the seeds of blackberries or 

 raspberries to the extent of 13 percent. It thus appears that the 

 shrike sometimes eats fruit. 



Animal food. — The animal portion of the shrike's food may be 

 divided into three parts : Insects, 83 percent ; spiders and a few snails, 

 etc., 2 percent ; vertebrates, 12 percent. 



Insect food. — In comparing the food of eastern subspecies of 

 shrike and the one under discussion, we find that more insects are 

 eaten by the western one. The figures for the eastern bird are: 

 Insects, 68 percent ; spiders, 4 percent ; vertebrates, 28 percent. The 

 difference is undoubtedly due to climate, the western bird being 

 able to find insects all the year round, while the eastern one discovers 

 very few during the winter. Insects probably are always preferred 

 when obtainable. 



