THE JOURNEYINGS OF BIRDS. 335 



magnetic pole, the migrating bird knows tlie location of this point and 

 is enabled to direct its course accordingly. It is perhaps needless to 

 say that this theory is not only unsupported by any serious facts but, 

 as has been shown by Baird, is opposed to the facts of migration in 

 North America. 



If during the migrations the older and stronger birds always led 

 the way, it might be said with plausibility that this faculty is due in 

 large measure to experience, but here again the facts are either con- 

 flicting or directly opposed to such a view, for it seems to have been 

 demonstrated with reasonable certainty that in Europe the young birds 

 not only precede the old, during the fall movement, but often travel 

 by a wholly different route. In this country, however, observations on 

 this point are limited and authorities differ, but the tendency is to be- 

 lieve that the old birds do actually lead. Observation is much needed 

 to settle this question. 



In the case of birds migrating over land areas, sight is supposed by 

 some to have an all-important function, especially when it is recalled 

 that a bird two miles above the earth is surrounded by a horizon line of 

 90 miles on either side. As already shown, they have been observed 

 at a height of three miles, which would easily keep them within sight 

 of prominent landmarks, and would even permit them to cross con- 

 siderable bodies of water without entirely losing themselves. That 

 they depend to some extent on such landmarks to guide them on their 

 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 hun- 

 dreds or even thousands of miles of open water, vision must play an 

 unimportant part. Mobius ('Das Ausland,' Aug., 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. We, therefore, seem inevitably led to the con- 

 clusion 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 civil- 

 ized races, more especially those accustomed 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 semi-circular canals of the ear. 



