1914] Bryant: Economic Status of tJtc Western 3Ieadouiark 403 



taking of an insect by a bird, can be considered the most potent 

 factor governing the food habits of birds. 



3. Hunger or inexperience fails to account for the destruction 

 of many of the so-called protected insects, because in many 

 instances they form staple articles of diet. 



4. The fact that cocci nellid beetles almost wholly escape the 

 attack of birds is the one thing that supports the theory that 

 certain arthropods are practically immune from the attack of 

 birds in spite of the fact that they are available as food. Tlie 

 logical explanation of the immunity lies in the possession of a 

 noxious secretion which makes them unpalatable. Why this secre- 

 tion should be more effective than that of the Pentatomidae or 

 certain tenebrionid beetles is not known. 



5. Insects protectively colored when at rest are easily detected 

 by birds or other enemies as soon as they move. An insect out- 

 side of its natural habitat also becomes easy to detect. These 

 factors of movement and change of habitat may explain the 

 occurrence of certain protectively colored insects in the diet of 

 the western meadowlark. 



6. The reflexes set up by the stimulus of the sight of food, 

 or, in other words, the psychological processes involved in the 

 taking of food, doubtless play an important part in the kind and 

 quantity of food taken. 



A number of factors govern the kind and amount of food 

 taken by birds. The totality of such factors (e.g., abundance, 

 palatability, ease of capture, conspicuoiLsness, etc.) can be ex- 

 pressed by the term availabilitij. Availabilify. thus iLsed, best 

 accounts for the varying food habits of birds. 



Although great progress has been made in economic ornith- 

 ology, there are still a number of problems that remain unsolved. 

 chief of which is the value to be placed on the destruction of 

 insects and weed seeds effected by birds. Since a solution of 

 this problem depends upon quantitative studies of the compar- 

 ative abundance of different species of insects and weed seeds, 

 economic ornithology must await such studies from the entomol- 

 ogist and botanist. 



Transmitted May 2, 1913. 



