250 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



British Columbia, Great Slave Lake, Central Keewatin, Maine, and 

 Muskegat Island, Massachusetts. It is credited by Cook (1911) 

 with being " the world's migration champion." After the breeding 

 season is over the bird repairs from the Arctic to the Antarctic 

 regions. " What their track is over that 11,000 miles of intervening 

 space no one knows," says Cooke (1911). 



A few scattered individuals have been noted along the United States coast 

 south to Long Island, but the great flocks of thousands and thousands of these 

 terns which alternate from one pole to the other have never been met by any 

 trained ornithologist competent to learn their preferred path and their time 

 schedule. The Arctic terns arrive in the far north about June 15 and leave 

 about August 25, thus staying 14 weeks at the nesting site. They probably 

 spend a few weeks longer in the winter than in the summer home and, if so, 

 this leaves them scarcely 20 weeks for the round trip of 22,000 miles. Not 

 less than 150 miles in a straight line must be their daily task, and this is 

 undoubtedly multiplied several times by their zigzag twisting and turning 

 in pursuit of food. 



The Arctic terns have more hours of daylight and sunlight than any other 

 animal on the globe. At their most northern nesting site the midnight sun has 

 already appeared before their arrival, and it never sets during their entire 

 stay at the breeding grounds. During two months of their sojourn in the Ant- 

 arctic they do not see a sunset, and for the rest of the time the sun dips only 

 a little way below the horizon and broad daylight continues all night. The 

 birds therefore, have 24 hours of daylight for at least eight months in the year, 

 and during the other four months have considerably more daylight than 

 darkness. 



Spring. — The most southern breeding place of the Arctic tern 

 seems to have been Muskegat Isle, off Nantucket. Mackay (1897) 

 gives the earliest date for the arrival of terns at this island as May 

 3, in 1897. The day before no terns were to be seen, while on the 

 third they arrived " in large flocks, thousands dropping from the 

 sky when they were first observed." The larger part of these were 

 common and roseate terns, but he found a few Arctic terns breeding. 

 When I visited this island in 1913 about 20,000 common terns, 1,000 

 roseate terns, and 3,000 laughing gulls were breeding, and I feel 

 fairly sure that I saw a couple of Arctic terns, so there is a possibility 

 that they still breed there. They were found breeding at Beverly in 

 1846 by Cabot (1846) and at Ipswich between 1868 and 1870 by 

 Maynard (1870). They no longer breed there. On the Maine coast 

 the Arctic tern, like the common tern, has steadily increased in num- 

 bers under protection since its low ebb due to the war of the milliners 

 in the late nineties. Its chief breeding grounds there, according to 

 Knight (1908), are Metinic, Green, Machias Seal Islands, and Mati- 

 nicus Rock, where it nests with the common tern. It arrives from 

 the south from the middle to the last of May. Its arrival on the 

 southern coast of Labrador is at about the same time. Turner 



