Inshore Oceanic Birds
The inshore zone, according to Wynne-Edwards (1935:240), "extends from high-water mark to a maximum of four or five miles out to sea, including islands and reefs within sight of shore." In Micronesia the majority of the Laridae occur in this zone including such residents as Sterna sumatrana, S. anaetheta, Thalasseus bergii, Anoüs stolidus, A. tenuirostris, Gygis alba. These birds, especially S. anaetheta, Thalasseus, and Anoüs, may venture into the offshore zone. Visitors to Micronesia include several terns which probably normally range in the inshore (as well as in offshore) zones, such as Childonias leucopterus and Sterna hirundo. These birds feed to a considerable extent inside the outer reefs surrounding the lagoons, coming to shore frequently in small or large groups. Gygis alba probably spends considerable time on shore; stomachs examined contained fish, crustaceans and insects, indicating that they obtain some of their food ashore.