The Search for Guano

The discovery of Peruvian island seabird guano as a potent agricultural fertilizer started a rush to find more in the Pacific and Caribbean.
Pacific Islands
1.  Enderbury Island
2.  McKean Island
3.  Howland Island
4.  Baker Island
5.  Canton Island
6.  Phoenix Islands
7.  Dangerous Islands
8.  Swains Atoll
9. Flint Island  
10. Caroline Island
11. Maidens Island
12. Jarvis Island
13. Christmas Atoll
14. Starbuck Island
15. Fanning Island
16. Palmyra Island
17. Kingman Reef
18. Johnston Atoll
19. Clipperton Island
Shortly after the Guano Islands Act passed in 1856, the United States and other nations claimed dozens of islands in the Pacific Ocean and Caribbean Sea. None of the guano found ever matched the quality of the nitrate-rich variety from Peru’s Chincha Islands. The Pacific and Caribbean guano did, however, contain quantities of other minerals like phosphate and potassium that were useful for agricultural fertilizer.
Once islands claimed under the act were mined out, most were abandoned, or their rights were sold to other parties hoping to get rich quick. A few are still “unincorporated and unorganized territories” of the United States.
Atlantic Islands
1.  Arenas Keys
2.  Alacranes Island
3.  Swan Islands
4.  Serranilla Keys
5.  Quita Sueño Island
6.  Roncador Island
7.  Serraña Key
8.  Petrel Island
9. Morant Keys
10. Navassa Island
11. Alta Vela Island
12. Aves Island
13. Verd Key