1 40 SEA-BIRDS 



is the well-marked diagonal fly-way of the arctic tern between New- 

 foundland and North- West Africa, which may involve a very large 

 proportion of the population of this tern in the eastern part of North 

 America. The arctic tern's migrations, indeed, are not only rather 

 complicated, but certainly more spectacular than those of any other 

 sea-bird; the little bird probably travels farther in the course of its 

 year than any animal in the world, except perhaps some whales. Its 

 travels are worth describing in some detail. 



It was previously thought by some workers, e.g. Seebohm (1885), 

 that, in spite of its circumpolar breeding-distribution, the arctic tern 

 had "not yet discovered the existence of the Pacific Ocean." Certainly 

 there seem to be rather few records on the eastern coast of the Pacific, 

 and practically none on the west side south of Kamchatka. But this is 

 probably because the arctic tern's passage is largely at sea; stragglers 

 have indeed been recorded in the Hawaiian islands and in the North 

 Island of New Zealand. The passage is detectable oflf and along the 

 California coast, and quite a number are found offshore along the 

 coasts of Peru and Chile. Even allowing for the relative numbers of 

 observers (there are practically none at sea in the Pacific), it seems 

 clear that the Atlantic passage is the greater, however. In late summer 

 and autumn very many are seen crossing the North Atlantic trans- 

 ocean shipping routes, and most, though not all, are passing at that 

 time from north-west to south-east. It would seem that many of the 

 arctic terns that breed in the north-west corner of the Atlantic, and 

 round the arctic waters that communicate with it, pass on a slant to 

 make their passage on the east side of the Atlantic. The (now famous) 

 ringing recoveries of arctic terns marked in Labrador (on the Red 

 Islands in Turnavik Bay) by O. L. Austin bear this out. One, marked 

 as young on 22 July 1927, was recovered at la Rochelle in France on 

 I October 1927; the other, marked on 23 July 1928, was found dead 

 at Margate, fifteen miles south-west of Port Shepstone, in Natal on the 

 south-east coast of Africa, on 14 November 1929 — it has flown at least 

 nine thousand miles in ninety days. A tern ringed on Eastern Egg 

 Rock in Maine on 3 July 1 9 1 3 and recovered at the mouth of the river 

 Niger in August 191 7 is now known to be an arctic tern (not a common 

 tern as was originally recorded). Three birds marked as young at 

 Machias Seal Island, belonging to New Brunswick but on the borders 

 of Maine, have been recovered across the Atlantic (O. Hawksley, 1949). 

 One marked on 20 July 1935 was captured near St. Nazaire in France 

 on 8 October of the same year. One marked on 5 July 1947 was found 



