248 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



that the adult gulls ate the terns' eggs and young, and the later were taking 

 their first chance to retaliate. This theory was strengthened by the fact that 

 we did not find nearly as many young terns as there ought to have been 

 with a colony as large as this. 



Fall. — As soon as the young are able to fly, usually in August, 

 many of the terns desert their breeding grounds and wander about 

 the shores in loose scattering flocks, free from the arduous cares 

 of reproduction, to spend the remainder of the season in rest and 

 recreation. They are still largely gregarious and may be seen resting 

 on the sand bars or sandy beaches in large compact flocks, all facing 

 the wind. Some may be bathing in the shallow waters or preening 

 their immaculate plumage, while others stand and sleep with bills 

 buried under the scapulars. As the rising tide encroaches on their 

 roosting ground those nearest the water are forced to rise, and 

 flying over their fellows, to alight above them on the sand. Birds 

 are constantly coming and going, making an animated scene of 

 lively interest. Their summer wanderings are often extended over 

 long distances in search of food. Large numbers of terns are seen 

 daily, flying high in the air over Cape Cod to their favorite feeding 

 grounds in Massachusetts Bay, spending the day on the sandy beaches 

 near Plymouth and returning each night to their breeding grounds 

 south of Cape Cod, 25 or 30 miles distant. The fall migration be- 

 gins on the coast of Maine by the middle or last of September. In 

 Massachusetts there are a few scattering winter records, but as a rule 

 they begin to leave early in October, and by the end of that month 

 nearly all of the common terns are gone. Winter records along the 

 Atlantic coast seem to be scarce north of Florida, and probably 

 most of the common terns spend the winter from the Gulf of Mexico 

 southward. 



DISTRIBUTION. 



Breeding range. — Along the Atlantic coast of North America from 

 northern Nova Scotia (Cape Breton) south to North Carolina 

 (Pamlico Sound) ; and in the interior, south to the Gulf of St. 

 Lawrence, the St. Lawrence River, northern Ohio (Oberlin and 

 islands in western Lake Erie), southeastern Michigan (St. Clair 

 Flats), southern Minnesota (Heron Lake), northern North Dakota 

 (Devil's Lake region), and southwestern Saskatchewan (Crane Lake 

 region). West to southeastern Alberta (Many Island Lake) and 

 central Alberta (near Edmonton). North nearly, if not quite, to the 

 Arctic coast of Mackenzie, certainly to Great Slave Lake (Fort 

 Providence) and the west coast of Hudson Bay. A few birds breed 

 in Bermuda, the Bahamas, and the Florida keys, on the coast of 

 Venezuela (Aruba and Bonaire Islands) and on the coasts of Ala- 

 bama, Louisiana, and Texas (Matagorda). In Europe, from Nor- 

 way to the Mediterranean, Black, and Caspian Seas, in the Azores. 



