Marine Science

Marine Science

Senior Theses 2008

Misty Carr (2008)  Foraging habits of the Black Skimmer (Rynchops niger)

Faculty Advisor: Elizabeth Forys

One large active breeding colony of black skimmers, Rynchops niger,  was monitored during the breeding season of 2007.  This colony (>300 pairs) was located on an urban barrier island on the west coast of Florida, USA.  I observed the colony for periods of 1-4 hours throughout the day and night and recorded the time skimmers left the colony to forage, the location they went to forage (the Gulf of Mexico or Intercoastal Waterway), the numbers that foraged together, and potentially relevant environmental factors (e.g., hours to sunset,  hours to sunrise, temperature, wind speed, tidal stage, tidal height,  and wave height).  I found that skimmers foraged throughout the night and were significantly most likely to forage closer to sunrise and sunset.  Because time to sunset and sunrise appeared to be important, I analyzed the portion of a 24 hour day that was closest to sunset separately from the portion of the day that was closet to sunrise.   During the hours closest to sunset, foraging increased significantly when it was closer to sunset and when the temperature decreased.   During the hours closest to sunrise, foraging increased significantly when it was closer to sunrise, and when there was a lower wind speed, lower tidal height and an outgoing tide.  When I separated the data according to location, I found that skimmers foraged in the Gulf of Mexico more frequently when the wind was lower and it was cooler.   They chose to forage in the Intercoastal Waterway during periods of higher winds and higher temperatures.  In addition, I found that skimmers primarily foraged alone.  My results indicate that breeding skimmers in my study area are solitary, crepuscular and nocturnal foragers which seek food when it is more concentrated and closer to the surface. 

Student Research