44 The Migrations of Birds 



course seems to be shown by the fact that they migrate mainly on clear nights 

 and are obliged to seek the earth on the approach of cloudiness and storms. 

 But in the case of birds migrating over hundreds or even thousands of miles 

 of open water, vision must play an unimportant part. Mobius (Das Ausland, 

 August, 1882) suggests that in such cases they may be guided by observing the roll 

 of the waves, but while this may be true in a few instances, it cannot possibly 

 be so in the majority of cases. As an example of this power of orientation it may 

 be mentioned that the members of the Harriman Alaska Expedition went by 

 steamer from the island of Unalaska to Bogoslof Island, a distance of some 

 60 miles. "A dense fog had shut out every object beyond a hundred yards. 

 When the steamer was halfway across, flocks of Murres, returning to Bogoslof 

 after long quests for food, began to break through the fog-wall astern, fly parallel 

 with the vessel, and disappear in the mists ahead. By chart and compass the 

 ship was heading straight for the island; but its course was no more exact than 

 that taken by the birds." COOKE. We therefore seem inevitably led to the 

 conclusion that birds are possessed of a "sense of direction." This "homing" 

 faculty or power of orientation, which is, for example, so strongly developed in 

 the Carrier Pigeon, is by no means unique among birds. It is possessed in a 

 greater or less degree by many animals, by most savage races of men, and not 

 infrequently by individuals among civilized races, more especially those accus- 

 tomed to life away from centers of civilization, in forest and on plain, just how 

 it is to be explained is difficult to say. Some would give it the dignity of a sixth 

 sense and would fix its seat in the semicircular canals of the ear. 



