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



Accurate knowledge in regard to the economic status and relative 

 abundance of the island birds was lacking, and there was little upon 

 which to base protective legislation. Knowledge was lacking also in 

 regard to practicable methods for increasing useful resident species ; 

 and, finally, as to the desirability of introducing exotic insectivorous 

 or other birds. 



Investigations were begun in December, 1911, and continuous field 

 work was carried on until September, 1912, permitting nine months 

 of consecutive observation. All the principal regions of Porto Rico 

 were visited, short trips were made to the adjacent islands of 

 Vieques and Culebra, and four days were spent on Desecheo Island, 

 in Mona Passage. As a result of this field work more than 2,200 

 stomachs of birds collected at all seasons were available for labora- 

 tory study and investigation, about 2,000 of which were collected by 

 the writer and the remainder acquired from other sources. The 

 examinations and results have additional importance as representing 

 the first extended work of the kind carried on within the tropical 

 regions of the Western Hemisphere. 



ITINERARY. 



The field work in Porto Rico covered the entire island and the 

 more important off-lying islands, with the exception of Mona. Ef- 

 fort was made to visit the main agricultural areas at different seasons 

 in order to study bird life in its relation to changing conditions of 

 season and cultivation incident to growth. Original conditions were 

 studied so far as possible by exploring the small areas of natural forest 

 still remaining. 



Beginning at San Juan, the capital city, on December 13, 1911, 

 work was continued on the island until September 11, 1912, as 

 follows (see PI. II) : 



San Juan, Dec. 13-15. 



Rio Piedras, Dec. 16-28. 



Fajardo, Dec. 29-30. 



Rio Piedras, Dec. 31-Jan. 4. 



Caguas, Jan. 5-14. 



Cayey, Jan. 15-25. 



Aibonito, Jan. 26-Feb. 4. 



Aibonito to Rio Piedras, Feb. 5. 



San Juan, Feb. 6-8. 



Mameyes, Feb. 9-Mar. 1. 



Hacienda Catalina, Mar. 2—12. 



Mameyes, Mar. 13-14. 



San Juan, Mar. 15. 



Vieques Island, Mar. 16-Apr. 4. 



Culebra Island, Apr. 5-22. 



Louis Pefla, or Southwest Cay, Apr. 11. 



Culebrita Island, Apr. 15. 

 Vieques Island, Apr. 23. 

 Naguabo, Apr. 24. 

 San Juan, Apr. 25. 

 Salinas, Apr. 26-May 2. 

 Yabucoa, May 3-11. 

 Patillas, May 12-14. 

 Ponce, May 15. 



Yauco, May 16-28. 



Maricao, May 29— June 5. 



Mayagiiez, June 6. 



Afiasco, June 7-8. 



Aguadilla, June 9-12. 



Desecheo Island, June 13-16. 



Aguadilla, June 17. 



Lares, June 18-July 1. 



Quebradillas, July 2-6. 



Manati, July 7-11. 



Ciales, July 12-18. 



Bayam6n, July 19-25. 



Comerio, July 26-31. 



Bayam6n, Aug. 1. 



Toa Alta, Aug. 2. 



Utuado, Aug. 3-9. 



Adjuntas, Aug. 10-16. 



Juana Diaz, Aug. 17-22. 



Ponce, Aug. 23. 



Cabo Rojo, Aug. 24-31. 



Cabo Rojo to Caguas, Sept. 1-2. 



Humacao, Sept. 3-9. 



San Juan, Sept. 10-11. 



