ARCTIC TERN. 221 



The peculiar distribution of this species, and the supposition that 

 the flocks never migrate down the shores of the Pacific, have led 

 some naturalists to suggest that the birds were originally confined 

 to the Atlantic Ocean, though ranging on both its eastern and west- 

 ern shores. The breeding area, they say, was gradually extended 

 east and west, one division of the birds going off along the north- 

 ern shore of America, the other across the end of Europe and 

 Asia, advanced flocks of each division finally meeting at Bering 

 Sea. But at the approach of winter these flocks separated at that 

 point, and ignoring the Pacific route to a milder climate, they fol- 

 lowed " hereditary instincts " and returned to the Atlantic, each 

 division migrating along its own path and wintering on its own 

 chosen shore, — the flocks of one wing ranging to the Middle 

 States, the others to the Canary Islands. 



The hypothesis is interesting and the facts are in the main cor- 

 rect; but it has been strongly hinted that the hypothesis has been 

 cruelly disturbed by the birds themselves, — they have turned up in 

 California. The hypothesis should not, however, be abandoned 

 because a few individuals have forsaken the traditions of their 

 race, — that is a common weakness of those who "go west." 

 Enough Arctic Terns still follow the ways of their fathers when 

 migrating, to prove the strength of this inherited tendency. 



In habits as well as in general appearance and manners this 

 species differs but slightly from the Common Tern. Our bird is 

 perhaps more graceful on the wing, though both fly with wonderful 

 grace and ease, and the Arctic Tern displays more boldness in 

 defence of its young or of a wounded companion. It seems utterly 

 fearless, and will advance so close as to strike with its pinions a 

 hand that menaces its young ; and when a colony is invaded by 

 any marauder, the Arctic Tern is the first to lead an attack upon 

 the intruder, and the attack is so fierce that the colony is usually 

 saved. 



The Arctic Terns frequent rocky islands and secluded portions 

 of the mainland, and in these localities the birds gather in large 

 communities. They may be seen sitting on a rock or stump, watch- 

 ing for their prey, in Kingfisher fashion. They float buoyantly on 

 the water, but rarely dive beneath the surface. 



Mr. Brewster considers their notes vary little from those of the 

 Common Tern though they can be distinguished. The usual cry 

 of the Arctic Tern resembles that of its congener, "but is shriller, 

 ending in a rising inflection, and sounding very like the squeal of a 

 pig." 



