Rynchops niger (Black Skimmer) is a colonial seabird that forages on small planktivorous fish that are caught while gliding just above the surface. Previous studies have found that baitfish abundance can affect skimmer productivity, so the purpose of this research was to determine the species and size of fish fed to chicks in Southwest Florida. During the 2015 and 2016 nesting seasons, we posted requests for photographs of Black Skimmer adults feeding chicks to several Facebook sites where photographers were posting images taken in Southwest Florida. We invited volunteers who were knowledgeable about fish to identify prey species. We received 256 photographs of which 211 could be included in our study. Black Skimmers fed chicks 22 different species of fish, including 9 that had not been previously recorded. The fish species did not differ by year, age of chick, or location; however, smaller chicks were fed significantly more small fish. Our research demonstrated that citizen science conducted through using photographs and social media is an accurate and efficient method of obtaining data about seabird diets.