12 



winter in Wyoming, near the hot springs, whose warmth keeps the neigh- 

 boring waters and ground from freezing. Nevertheless, it is as yet un- 

 explained why some birds, notably many of the warblers, retire in winter 

 to such a great distance south, some even crossing the equator and pass- 

 ing several hundred miles beyond. Certainly neither cold nor hunger 

 can be the cause of such wanderings. 



It has been often noticed that during the fall migration many birds 

 seem to be able to foretell the approach of storms from the north, and 

 hurriedly depart southward, before human eyes can detect any signs of 

 the coming change. There is a large accumulation of evidence on this 

 point, all seemingly in support of the proposition which has been for- 

 mulated by one of our leading ornithologists in the following words : 

 "Birds discern approaching meteorological changes."* Some ornithol- 

 ogists deny this, saying that in such cases the birds have out-traveled 

 the storm, in which they were at first caught, their superior powers of 

 flight enabling them to pass ahead of it ; or that they have been warned 

 by the hasty approach of more northern birds coming from the area 

 over which the storm was moving. 



If we study fall migration merely, there seems to be no doubt of the 

 truth of this statement, but if we include spring migration the question 

 becomes much more involved. If birds discern approaching meteor- 

 ological changes, why is it that so many thousands perish each year 

 by being caught in storms and frozen to death ? Certainly an approach- 

 ing storm in spring must give just as plain and early a warning as one 

 in the fall, yet the same birds which are said to foresee it at the latter 

 time and escape, rush blindly forward a few months later and are over- 

 taken, their death paying the penalty of their rashness. The hardy 

 waterfowl (Ducks and Geese) push northward in the spring, encounter 

 storms, and are turned back, only to repeat the same thing a dozen 

 times before they reach their summer quarters, but each time, instead 

 of avoiding the approaching storm.; they do not retreat until its actual 

 presence drives them back. If they can foresee these changes, then 

 their love of home and their desire to return to it must be wonderfully 

 strong. 



SPEED AT WHICH BIRDS MIGRATE. 



In studying the speed at which birds proceed northward in their mi- 

 grations one is beset by many difficulties. To determine the compara- 

 tive speed of the several species is easy enough, but to determine the 

 absolute rate — the exact number of miles which a particular bird makes 

 during one day's journey — is beyond our power. If migration were a 

 steady movement northward, with the same individuals always in the 

 van, numerous careful observations might make it possible to arrive at 

 an approximation to the truth ; but instead of this, migration is per- 

 formed something after the manner of a game of leap-frog. While in 



*J . A. Allen, in Scribner's Monthly Magazine for October, 1881, p. 938. 



