70 Wild Birds and their Haunts 



subject of much interest to naturalists, and with a view to 

 obtaining definite information upon the subject a large 

 number of these birds were captured some two years ago 

 by naturalists in Prussia, and a light metal ring, bearing 

 a number and the date, was fastened to one foot of the 

 bird, which was then set at liberty. 



One of these birds — a lake fowl, bearing the date of July 

 26, 1907 — was shot in El Bahira, Tunis, and a stork, dated 

 July 5, 1907, was killed at Fort Jameson, Rhodesia, far 

 beyond the Equator. It has long been known that the 

 house stork winters in great numbers in Egypt, and that 

 they have often been seen in Central Africa and German 

 East Africa ; and it is no new discovery that they should 

 fly so far as from North Germany to South Africa. 



Another authority says : — 



" In the feathered world migration plays a most 

 important part in the life of each little songster of wood 

 and field. We know the why and the wherefore of the 

 autumn or southern flight ; it is entirely a matter of food 

 supply. As for the northern or spring flight we can 

 assume no logical reason. Why the birds should desert 

 a land of plenty and attempt a journey often thousands of 

 miles in extent, often reaching their summer homes before 

 the snow and ice of winter have released their hold on 

 earth and tree, is at present a mystery, and perhaps ever 

 will be." 



The query as to the causes of the northern or spring 

 exodus has prompted me to make an effort to explain, at 

 least in some measure, those laws which govern migra- 

 tions, not only of birds, but of certain of our mammals 

 as well. It is a subject of which, so far as I am in- 

 formed, but very little of an explanatory character has 

 been written. Anything which may here be advanced 

 shall be of a tentative nature. The basis of my explana- 

 tions will be the recent theory of Dr. Marsden Manson, as 

 stated in his " Evolution of Climates." 



This theory has been accepted by many of the advanced 

 scientists of to-day throughout the world. Professor 

 Schaberle, formerly of the University of Michigan, has 

 recently announced that Dr. Manson 's theory may be 



