Bonaire is home to the largest natural flamingo reserve in the western hemisphere, housing one of the four remaining crucial breeding grounds in the world and the primary breeding ground of the Americas. Flamingos filter feed on gastropods, crustaceans and chrinomids in salt water lakes and ponds. This study examined flamingo distribution and feeding behavior in relation to changing salinity levels in condenser ponds used for salt production on Bonaire, Netherland Antilles. Flamingo density was found to be highest (44.4-172.7birds/km2 ) in ponds with the highest salinity (184-205g/l) among the ponds tested, followed by ponds with the lowest salinity (55 g/l). Ponds with an intermediate salinity (84-154 g/l) hosted significantly fewer birds (0-1.6 birds/km2 ). The type of feeding behavior used by flamingos was found to be related to water depth and salinity range and could possibly be explained by differences in prey found at different salinities and depths; however, this specific question was only addressed in a qualitative manner in this study. Grubbing was most prevalent in high salinity ponds while skimming occurred with higher frequency in low salinity ponds. Because grubbing is generally used to feed on pond bottoms results suggest that prey items in high salinity ponds may be densest at the bottom and probably consist of chrinomids such as brine fly pupae. Conversely, skimming is used in shallower water and its prevalence in low salinity ponds indicates that prey is concentrated in the water column and best caught by filter feeding mechanisms.
This student research was retrieved from Physis: Journal of Marine Science III (Spring 2008)19: 1-5 from CIEE Bonaire.