OCTOBER, 1902. 
THE MIGRATION OF BIRDS, 
181 
place in a general north and south direction in eastern Europe (9). 
Although he fell into serious error regarding migratory routes, 
his methods of investigation were good and acted as a stimulus to 
other ornithologists throughout Europe and western Asia. An- 
other important advance was made in 1866 by Dr. Baird when he 
traced the lines of dispersion of a number of American birds and 
intimated very strongly that birds followed certain geographical 
features in their migrations (10). Baird's work is of great im- 
portance. He certainly anticipated the work of Palmen. It is in- 
deed peculiar that a work of such importance did not immediately 
stimulate others to direct their efforts along these lines. 
Palmen saw the necessity of pursuing a definite course of in- 
vestigation and followed these initial movements by studying in 
detail the routes of a small number of hyperborean species. In 
1876 he published his results under the title, ''Ueber die Zugstras- 
sen der Vogel" (11). Beside having thus laid the foundation for 
the study of most migration phenomena he immediately reaped 
some of the results that were to follow. He not only showed 
that definite routes were followed, but established definite fly- 
lines for entire Europe. Through these investigations we may 
also say he fixed our present laws regarding migratory routes, 
namely, that these routes are geographically defined courses. 
These principles of Palmen were at first rejected from nearly 
all sides. His statements were not only looked upon as con- 
jectural but even rash. However, as investigation proceeded, 
the importance of his work gradually became more and more evi- 
' dent and it was quite soon accepted (12). 
With the increasing interest in migration among zoologists the 
time was ripe for theory. Prior to the work of Palmen the the- 
oretical side of the question was largely speculative. One the- 
ory which had some influence in the scientific world was that of 
the Swedish poet Runeberg who claimed that migration was 
caused by the season of perpetual darkness in the north. He con- 
ceived the idea that as darkness gradually fell over the north 
pole the birds were attracted southward where there was more 
light. Another interesting case is that quoted by Prof. Newton 
from the London Times for September 18, 1874, which professes 
to give the latest accepted theory : 
9. Die Isopiptesen Russlands. Mem. Imp. Acad, of Sciences of St. 
Petersburg, 1859. 
10. Baird. Amer. Jour, of Science, 18G6, 
11*. Palmen, Ueber die Zugstrassen der Voegel. Leipzig, 1876. 
12. Nature, vol. 15, p. 465; vol. 11, p. 433. Journal f. Ornith., 1876, 
p. 390. 
