XIV 



MIGRATION 357 



fact that the Bluethroat always arrives at dawn and 

 not during the dark at the lighthouses. But though 

 this may show that its flight has been a long one, it 

 tells us nothing definite about the time and place 

 of starting. The non-occurrence of this particular 

 Bluethroat in Germany may be due to defective 

 observation. Professor Newton gives an instance of 

 a bird making a flight of extraordinary length. A 

 kind of Cuckoo (Eudynamis Taitensis) that is found 

 almost throughout Polynesia, every year makes a 

 voyage to New Zealand to breed. A glance at the 

 map will show that it must pass great tracts of sea. 

 Still there arc small islets, such as Norfolk Island 

 and the Lord Howe Islands, which it may possibly 

 use as resting places. Occasionally representatives 

 of American species are found in Europe and 

 undoubtedly they have crossed the Atlantic, which 

 has a breadth of over 2,000 miles at its narrowest 

 point. They cannot have crossed the Behring Strait 

 and flown over Asia to Europe, since the)' are hardly 

 ever found in Germany. But they may have either 

 rested on a ship on their way, or been borne along 

 involuntarily by violent gales. Such performances 

 cannot well be ranked with long flights voluntarily 

 and habitually undertaken. Setting such exceptional 

 phenomena aside, perhaps the longest known flight is 

 one which I have already mentioned. The Ameri- 

 can Golden Plovers breed in Arctic regions, from 

 Alaska to Greenland, above the limits of forest 

 growth, and when autumn comes they pass through 

 Nova Scotia, strike boldly out to sea, and, generally 

 leaving the Bermudas well to the west, sail on over 



