lOUJ Bryant: Economic Status of the Western Mcadowlark 481 



efficiency of warning and cryptic coloration in protecting animals 

 from their enemies," clearly points out the fact that the tests of 

 protective adaptations against natural enemies have been incon- 

 sistent, misinterpreted, and are untrustworthy guides to behavior 

 under natural conditions. 



Investigators using the experimental method have too often 

 failed to take into account other factors instrumental in modi- 

 fying the behavior of animals toward their prey. "The rejection 

 of various items of food by captive animals does not prove that 

 these items are rejected by the same species under natural con- 

 ditions." It does give some idea of the food habits, but does 

 not furnish dependable evidence as to the food of birds in the 

 wild. 



More reliance can be placed on the evidence furni.shed by 

 stomach examination, for "there is no possibility of going back 

 of such evidence on the choice of food." Its one drawback is 

 that it does not furnish us with data as to what was not chosen. 



Hence the following evidence must be considered as valuable 

 in throwing light upon this much discussed problem. The dis- 

 cussion will be largely directed to such protective adaptations as 

 stings, noxious secretions, hairs, etc., as the evidence at hand 

 bears more directly on this phase of the subject. 



More has been written on the palatability of butterflies than 

 on any other insect. To back up the theory of mimicry it was 

 necessary that birds be made an important enemy of butterflies. 

 That birds are an important enemy of butterflies still remains 

 to be proved. The fact that the records of the United States 

 Biological Survey show that in the examination of 40,000 .stom- 

 achs of birds but four cases have been found where the birds 

 concerned had eaten butterfles would support Mr. McAfee's 

 contention that "butterflies are in very little demand with birds 

 in the United States." On the other hand, the fact that eleven 

 butterflies have been taken from the stomachs of western meadow- 

 larks and that five different species of birds were found feeding 

 on butterflies, to a greater or less extent, during an outbreak of 

 these insects in northern California during the spring and sum- 

 mer of 1911 (Bryant, 1911), shows that butterflies are taken to 

 some extent as food. The observational evidence of Mr. Tyler 



