Caspian Tern        Hydroprogne caspia



This large, stocky, gull-like bird (body length of 21 inches) is the largest of our local terns and has a thick red bill with a touch of black on the tip. Terns can be distinguished from gulls by their sleeker appearance, black cap and feeding behavior of constant over-water flight and plunge-diving for fish.  Caspian terns are usually seen in small hunting groups around Puget Sound during the summer months.  They communicate with each other using a heron-like squawk.


The species can be found world wide and in fact is named for specimens obtained from the Caspian Sea of southern Russia. This picture was taken at the Salton Sea in southern California at the northern part of their wintering grounds.  There they feed on a small introduced fish called Tilapia which is the only surviving fish in the Salton Sea due to the high salt content.  


They breed in North America near water on freshwater and estuarine islands where there are wide open spaces. There they lay one to three pale blue green eggs among gravel and sand.  Incubation lasts for 26-28 days.


Caspian terns were initially found in eastern Washington in the 1930's.  They began breeding in the 1950's on Sand Island in Grays Harbor moving south to the Columbia River estuary in the 1980's where thousands use dredge spoil islands forming the world's largest Caspian tern breeding colony.  The large number of terns has had an impact on juvenile salmonids migrating through the lower Columbia.  Studies are underway to develop means of dealing with the predation.