Page:Popular Science Monthly Volume 11.djvu/426

410 during the intervals of migrations; and the Kjölen range was probably selected as their habitat, not because it was proved to be so, but because so little is known about it at all. The answer to the second question is certain: They go to the sea. Those on the east of the backbone of Norway go to the Gulf of Bothnia, and those on the west to the Atlantic Ocean (Fig. 4), and out of eighteen migrations which have been investigated, one only, and that very doubtful, is reported



to have been directed southward. The question as to the cause of these migrations remains, and is a very difficult one to answer. We have been told that the foreknowledge of approaching severe weather predetermines the exodus: my experience, however, contradicts this, and it may be dismissed as merely a popular superstition. Unusual reproduction and consequent deficiency of food is a more plausible theory; but I have always noticed that, just as with the swallow, a