Common Terns occur in both the Old World and in America.
In Ontario they breed on exposed shores from Lake Erie north to the northern limit of the Precambrian Shield.
Banding has shown that our birds winter south to Ecuador in South America.
Adults are difficult to distinguish in the field from Forster’s and Arctic Terns. The combination of red bill with black tip, white tail with thin black outer edges, the “tee-arrr” call are filed marks of adults: the young have black napes.
These three species are about the size of Bonaparte’s Gull but have much more deeply forked tails and lack the black hood of adult Bonaparte’s Gull.
Dr. J. Murray Speirs