MIGRATION OF PACIFIC PLOVER HENSHAW, 547 



casuals, and the accidentals, the visiting birds make quite a respect- 

 able winged ann}^ 



Islands accidentally discovered hy 'present migrants. — It is not 

 supposable that birds ever put to sea to seek unknown lands by a 

 hitherto untraveled route. AVe know that millions of birds of many 

 species are annually or semiannually driven out to sea by storms, 

 especially species that migrate near the seacoast. Many, perhaps 

 most, of these storm-driven waifs never see land again, but become 

 wing Aveary and find watery graves. Some few, however, reach 

 safe havens in oceanic islands, and in this way, no doubt, such islands 

 have received their bird colonists. 



That the golden plover, like the other migrants from the North 

 American coast, discovered Hawaii accidentally is hardly open to 

 doubt. I see no necessity for presupposing the existence of sunken 

 continents or of ancient continental extensions to account for the 

 presence on the islands of the plover and other North American 

 birds, like the night heron, gallinule, and coot. The presence there 

 of the weak-winged passerines is another matter, and it must be 

 admitted that proof of the existence of an ancient continent, stretch- 

 ing from the islands southward toward Australia, would simplify a 

 very difficult problem. So far, however, as our North American 

 birds are concerned, it need be assumed only that long ago some 

 thousands of Pacific plover and other species, when following the 

 usual southward migration route along the Asiatic coast in fall, were 

 accidentally driven to sea, and that a greater or less number were 

 able to maintain themselves on the wing long enough to make a lucky 

 landfall of the low islands to the northwest of Hawaii. The flight 

 from Japan to the nearest island eastward would involve a flight 

 about as prolonged as that from the Aleutian Archipelago to Hawaii, 

 or some 2,000 miles. The chain of low islets once gained, it would 

 be but a quastion of time for migrants, step by step, to reach the 

 larger islands of Hawaii, 1,700 miles or so to the eastward. After win- 

 tering, a sufficient number may have essayed the flight back across 

 the ocean to the Asiatic coast the following spring, and then north- 

 ward to their Siberian breeding grounds with their Asiatic fellows. 

 Having once discovered the islands and learned their suitability as 

 winter quarters, they would no doubt return over the same route, 

 and thus in time establish a regular fly line or migration route from 

 the Asiatic mainland to the islands. Later, as the position of the 

 islands became better known, the part-land, part-water route would 

 naturally be exchanged for a shorter all-water route. It is possible, 

 however, that the old Asiatic route has never been wholly abandoned 

 and that it is still favored by a certain number of the island migrants; 

 for plover, turnstones, curlew, and tatlers have been observed on 

 Laysan, about 600 miles northwest of Hawaii, late in May. These 



