BUREAU OF BIOLOGICAL SURVEY. 437 



The chief fur expert of the Biological Survey made an extended 

 trip among the blue-fox farms of Alaska during the early part of 

 the year on the bureau's power cruiser Sea Otter and obtained valu- 

 able information which it is intended to publish in a bulletin on 

 the blue-fox farming industry. In cooperation with the chief fur 

 warden of the bureau and representatives of the Forest Service, he 

 assisted in the organization of two associations of blue-fox farmers. 



FOOD HABITS RESEARCH. 



EXAMINATION OF STOMACHS OF BIRDS. 



In the course of the fiscal year 2,302 stomachs of birds were re- 

 ceived and incorporated in the collection, preparatory to examina- 

 tion. Laboratory work on the examination of various bird stomachs 

 included 561 English sparrows, making the total examined for this 

 species about 5,100. Examination of the stomachs of five species of 

 shore birds has been completed and the data secured therefrom tabu- 

 lated, preparatory to the preparation of a report on their economic 

 status. In a continuation of a study of the food of birds of prey 331 

 stomachs and 248 pellets representing 10 species were analyzed. Con- 

 siderable recently acquired material of fish-eating birds has been ex- 

 amined with the object of incorporating the data obtained in the 

 manuscript previously prepared on the food habits of these birds. 

 Additional material examined includes stomachs of band-tailed 

 pigeons, studied in their relation to grain crops in California, and 

 of domestic pigeons in relation to an imported snail now destructive 

 in the vicinity of La Jolla, Calif. 



In response to a request from persons in the Dominican Republic 

 engaged in raising cacao, examination was made of two lots of stom- 

 ach material of the " carpintero," a woodpecker having rather pro- 

 nounced vegetarian habits. From the food preferences revealed it is 

 apparent that this bird may become destructive to corn and the 

 cacao, into the green fruit of which it drills holes to feed on the pulp. 

 Other examinations made for correspondents included stomachs of 

 ruffed grouse, from NewEngland; pileated woodpeckers and pigmy 

 owls, from Oregon; several species of hawks and owls, chiefly from 

 New York; crossbills, from Illinois; swifts, from Washington; and 

 wild ducks, from Argentina. 



PINYON JAY CONTROL. 



The status of the pinyon jay in its relation to grain crops was 

 investigated during the year, and measures for control during the 

 corn harvest were devised. Damage by the bird to wheat also occurs 

 when it is in the shock, and the year's efforts were directed toward 

 finding effective and economical means of control during that period. 

 Experiments conducted in Colorado indicated that poisoning is only 

 moderately successful during the wheat harvest and is economical 

 only in small fields so situated that there is likely to be a concen- 

 tration of jays in a limited area which can be baited. The great 

 danger of killing mourning doves through poisoned baits placed in 

 wheat stubble precludes the possibility of extensive poisonmg cam- 

 paigns against pinyon jays during the wheat harvest. Recommenda- 

 tion was made, therefore, that control measures for these birds be 



