BIRDS OF PORTO RICO. 107 



NORTHERN PARUXA WARBLER. Compsothlypis americana unnea'. Brewster. 

 Reimta, Pecho de Oko. • 



The parula warbler was the most common of the migrant warblers in Porto 

 Icico. It is found everywhere in forest growth, and occurs frequently in mango 

 trees in pastures. In the forest it is the noisiest of the birds that gather to 

 scold an intruder, and is always active, working quickly through the limbs or 

 catching insects on the wing. Bowdish (1902-3, p. 18) records the first fall 

 birds October 25, 1901, and November 5, 1900, and in 1912 the last were observed 

 near Salinas April 30. One was observed, March 8 at 3,000 feet elevation on 

 El Yunque. Migratory movement was apparent among them by February 14, 

 and after this the birds were very restless, especially during early morning, 

 and there was a tendency to work from east to west. In March and April 

 there were distinct waves of migration. 



Food. — In studying the food of the parula warbler 61 stomachs from Porto 

 Rico were examined, representing the months from December to May, inclusive, 

 and all parts of the region under discussion. Animal matter amounts to 97.7 

 and vegetable to 2.3 per cent. The vegetable matter consisted of seeds of small 

 berries of the camacey (Miconia prasina) and others and was found in five 

 stomachs collected in December, January, and February. 



The animal food is of much more importance and includes a large number 

 of insect pests. Lantern flies (Fulgoridse) (19.09 per cent) were identified in 

 29 stomachs. These with other homopteran remains (6.85 per cent), partly of 

 the same family and partly from closely allied groups, all of which are harmful, 

 show that a little more than one-fourth of the entire food is composed of these 

 pests. Other bugs (3.69 per cent) comprise small numbers of leaf bugs, species 

 of the chinch bug family, stinkbugs, and a few predacious assassin bugs. 

 The birds are fond of beetles, and this order supplies 22.53 per cent of the food, 

 nearly all being injurious species. Ladybird beetles (1.36 per cent) were pres- 

 ent in- 14 stomachs. Longicorn beetles (1.6S per cent) were taken 11 times, and 

 leaf beetles of several species (7.95 per cent) were eaten by 30 of these birds. 

 The major portion belong to the abundant genus Cryptoceplialus, and several 

 species are represented. Darkling beetles figure as 1.01 per cent and skin beetles 

 0.45 per cent. Scarred-snout weevils were eaten by eight birds, and among these 

 the coffee leaf- weevil (2.02 per cent) was taken three times at least. Other 

 weevils (2.57 per cent) include two shot-hole stalk-borers, several curculios, and 

 others. Miscellaneous beetle remains make up 5.49 per cent. 



Ants (0.17 per cent) were eaten five times, while other Hymenoptera, all 

 small species, come to 3.57 per cent. Flies were captured by five birds and 

 amount to 1.19 per cent. In 18 stomachs were caterpillars, sometimes mere 

 fragments of skin, and in four others occurred moths. These together com- 

 prise 10.44 per cent of the total food. Fragments of spiders (29.53 per cent) 

 were identified in 29 stomachs. A small portion of miscellaneous animal mat- 

 ter amounts to 0.26 per cent. 



From the tabulated data as presented above the beneficial insects, counting 

 the large number of spiders, amount to practically 35 per cent, and harmful 

 species form the rest of the bulk exclusive of the small percentage of vegetable 

 matter. The bird is thus seen to be a beneficial species. In winter it is the most 

 abundant of the warbler family on the island and frequents localities where it 

 can do much good ; so that while not resident, it is one of the most valuable 

 of the regular migrants. 



