R. Clapp 1964 Oct. 11 Sibylla Island, Taongi Atoll Four Black naped Terns were seen in an open area between the southern end of Sibylla and the next islet. They would be very difficult to distinguish from Fairy Tern at any great distance. The most distinctive identifying "mark" is the call which is typically rasping "Sterna" in nature. Of three reef herons seen on this morning's excursion one was white and the other two were intermediate "mottled" forms.