Seabird Picture of the Month, March 2006:
Caspian Tern
photo by Kirsten Bixler

In the summer of 2003, a new colony was established by Caspian Terns at Dungeness National Wildlife Refuge; located on the north coast of Washington State and the eastern edge of the Pacific Ocean. In 2004 and 2005, I monitored these birds from an observation blind overlooking the colony. The daily and seasonal activities of Caspian Terns are dependent upon small marine forage fish, and their behavior in catching and handling prey is sometimes breathtaking.

A foraging Caspian tern flies silently with its massive orange-red bill pointing down.  It performs an effortless dive, plummeting three to thirty meters from the air into shallow water, and if perfectly accurate, plucks up a fish. The tern adjusts its grip on the extremely slippery prey with ease and swallows it head-first to avoid potentially dangerous spines. If the fish is not consumed immediately, the bird transports it crosswise in the bill back to the colony.

Early in the breeding season, the Caspian tern uses its prey to attract a mate by parading it flirtatiously through the colony with slightly muffled but strident calls. Once a pair bond is firmly established and one to three eggs produced, both members will share the tasks of incubating and providing fish for its mate. When chicks finally emerge, adults manage to capture and deliver tiny fish. As the chicks grow, their proficiency in handling prey increases, as does the size of the food items supplied to them. The chicks however, require food from adults for several months after fledging, until they fully acquire the skill of plunge-diving. The photograph above allows a glimpse of the level of dexterity possessed by these graceful birds.

Text by Kirsten Bixler, USGS Alaska Science Center

To learn more about other seabirds, browse the Seabird Flash Cards on the Seabird Page of this website.