8 BULLETIN 326, U. S. DEPARTMENT OF AGRICULTURE. 



latitudes. The food of resident birds in the United States shows in 

 many instances a predominance of insects in the warmer season and 

 of vegetable matter in the winter months, though many specialized 

 forms may feed on one or the other throughout the year. In Porto 

 Rico, because of the even temperature and slight climatic changes, 

 birds are not forced to vary their diet ; consequently the percentages 

 of animal and vegetable food are relatively stable from month to 

 month, and a bird is vegetarian or predacious, or both, throughout 

 the year, according to its natural bent. Young birds of partially 

 insectivorous species, when abandoned by their parents and left to 

 their own resources, often feed largely upon berries and other vege- 

 table matter, but as they become more adept secure the same kind of 

 food as their parents. 



Among resident forms, birds belonging to families which in tem- 

 perate latitudes feed almost entirely on insects, eat great quantities 

 of vegetable matter. This is especially noticeable among flycatchers. 

 Of the five forms inhabiting these islands only one, the bobito 

 (Blacicus hlancai), is truly insectivorous; the others, all birds of 

 fair size, consume many more berries and wild fruits than do their 

 representative forms in the north; and one, the elainea (Elainea m. 

 martinica), is almost entirely vegetarian. Small wild fruits and 

 berries abound at all seasons, offering an easily obtainable food sup- 

 ply. Some Xorth American migrants, predacious in their northern 

 homes, here follow the example of native forms and feast on the 

 bountiful crop of berries before them. 



In Porto Rico, birds which feed on wild fruits almost entirely, as 

 the spindalis, are not at all injurious. The coffee berry, with its 

 sweet outer covering, is the only important small cultivated fruit, 

 and from the evidence available it is left untouched by birds, though 

 two species are locally believed to eat it. The distribution of seeds 

 of wild fruits can not be charged against the birds, as none of the 

 plants or shrubs disseminated are of importance as noxious species. 

 Small grains are grown in comparatively small areas and are little 

 eaten by birds. The few kernels of corn taken by blackbirds amount 

 to nothing, and none of the seed-eating pigeons examined had taken 

 grain. 



Among the common birds found in Porto Rico none, fortunately, 

 may be called wholly pernicious. The small bird-eating Accipiter 

 found at Maricao is certainly injurious, and its larger relative, the 

 red-tailed hawk, is troublesome when it acquires a taste for poultry ; 

 but some species, while to a certain extent destructive, make up for 

 their damage in other ways. Several birds eat large numbers of 

 lizards and tree toads, seemingly without reducing their numbers, 

 as these creatures are to all appearances as abundant as is possible. 



