414 Recent Literature. [july 



fication of birds ' food is of the utmost importance, and especially with 

 regard to the insect portion. Economic ornithology is, therefore, a sister 

 science to economic entomology, just as much or perhaps even more 

 so than botany. To aid agricultural interests, nature is called in practically 

 and artificially, and every effort should be made to use such helps from every 

 possible source. Wild birds are the source in question here. . . . We can 

 .... by encouragement of useful species and destruction of harmful ones, 

 check the attacks of insects on crops, and enable the country to increase 

 crop outturns, and in every way benefit agricultural and therefore the 

 country's interest." (p. 5). 



It is interesting to note that Mr. Mason has reached the same conclusion 

 about several points as have economic investigators in the United States. 

 For instance, his opinion as to the low value of generalized statements 

 founded on field observations on the food of birds agrees with our experience. 

 He properly esteems field observation, however, as a valuable supplement 

 to stomach examination. Mason doubts the value of observations on caged 

 birds, saying " if the natural food is bub vaguely known, we learn practi- 

 cally nothing by this method." (p. 15.) Indian birds, like those of the 

 United States, are very fond of grasshoppers. " They are eaten by practi- 

 cally every species of insectivorous bird, and form one of the main supplies 

 from which birds in India draw their insect food." (p. 325.) Fondness for 

 Scarabaeidae and weevils is alsj characteristic of birds of both countries. 

 Mason says furthermore that fcutterflies do not form any appreciable 

 proportion of the food of any . . species of bird," a conclusion agreeing 

 perfectly with experience in the United States. We have been informed 

 however by supporters of the mimicry theory that in the tropics all is 

 different and that butterflies are freely eaten by birds. Mason's data from 

 the examination of the stomachs of tropical birds is by no means the only 

 evidence that these statements are highly speculative. In commenting 

 on Frank Finn's experiments in feeding butterflies to birds, which Finn 

 at the time thought afforded proof that there is a natural taste for butter- 

 flies among birds, Mason justly remarks " they have little importance to 

 economic ornithology since most of the experiments were conducted with 

 caged birds, these therefore being under unnatural conditions." (p. 338.) 



Mason makes some very justifiable remarks on the economic value of 

 seed-eating birds, expressing views which may be more or less justly applied 

 in the United States. He says: " In India I consider a bird eating weed 

 seed as of no value whatever. They may keep weeds down to a certain 

 extent, but this is of minor importance in a country where labour is cheap 

 and where farming is not practised on such intensive lines as elsewhere. 

 Even in intensive cultivation we cannot rely on weeds being kept down by 

 birds and the expense of cultivation to eliminate weeds is, I believe, not 

 reduced in the slightest by the action of birds." (p. 9.) In addition to 

 this he says: "We can attach little, if any, importance in India to weed- 

 seed or weed-eating birds; we attach no more importance to them than we 

 do to weed eating insects. As a rule a weed-seed eating bird is spoken of as 



