BUREAU OF BIOLOGICAL SURVEY. 665 



beins: tabulated. Thus tlieir relations to agriculture and horticul- 

 ture are easily stated, whether beneficial or injurious, -and approxi- 

 mately the extent of the good or harm they do. Besides examina- 

 tions of special i^roups of birds on which the Biological vSurvey is 

 preparing reports, the work includes the examination of small col- 

 lections made by request of State officials. During the year the fol- 

 lowing investigations of this character have been made: 



A large series of stomachs of the marsh hawk was examined for 

 the Commission of Fisheries and Game of Massachusetts. These 

 birds were collected near the heath hen preserve on Marthas Vine- 

 yard and were found to have fed largely on birds, including some 

 heath hens. The marsh hawk in most regions rarely molests birds, 

 but feeds chiefly on mice and other small rodents. On Cape Cod, 

 Massachusetts, however, the marsh hawk lives to a considerable 

 extent on poultry and small birds and hence must be classed locally 

 as a harmful species. 



An effort having been made to remove protection from gulls in 

 Louisiana, a correspondent of the Biological Survey who is interested 

 }n protecting these birds sent up a series of stomachs of Franklin's 

 gull in order that definite proof might be had of the bird's economic 

 relations. The food was found to be almost exclusively insectivorous 

 and the bird therefore beneficial. 



A number of birds taken in midwinter on Staten Island were 

 examined for the Staten Island Association of Arts and Sciences. 



The stomach contents of several Cape iNIay warblers were examined 

 for a member of the West Virginia Experiment Station. The birds 

 were puncturing grapes when shot and information was wanted as 

 to whether they were feeding upon any insect enemies of the grape. 

 Their trait of injuring grapes is in evidence onlj' during a very small 

 proportion of the year. At times the birds are almost exclusively 

 insectivorous. 



Other work of the same general nature included the examination 

 of a small collection of duck stomachs from Indian River, Florida, in 

 connection with recommendations to a shooting club in that vicinity 

 regarding plants to be used for attracting ducks. 



Some stomachs of horned toads were examined for the Bureau of 

 Entomology in order to learn the relation of these animals to the 

 injurious false wireworms of the Northwestern States. 



COOPERATION WITH THE ISLAND OF PORTO RICO. 



During the year a request was received from the board of agricul- 

 tui-e of tlio island of Porto Rico for cooperation in an investigation 

 of the bird life of the island with a view of ascertaining the part 

 played by the species native to the island in the destruction of insects 

 jnimical to crops. Accordingly an assistant of the Survey was de- 

 tailed to make the necessary investigation, the expense incident to 

 the work being borne in large part by the (l(>par(ment of agriculture 

 of the island. The work is now well under way and from facts 

 already ascertained it appears that the island is deficient in insect- 

 eating bird=. Unfortunately the presence of the mongoose in Borto 

 Rico, where it was import od years ago to destroy the cane-oating rats, 

 greatly complicates the situation. It has already destroyed most of 



