Ill 



"The reason for these migrations is not satisfactorily explained. That 

 they are caused by want of food is hardly probable, as the squirrels are 

 found to be fat at the time, and as often leave localities abounding with 

 food as otherwise. After one of these grand migrations, very few of the 

 species are found in the localities from which they have moved, and 

 these, as if alarflaed at the unusual solitude, are silent and shy. They 

 rapidly increase in numbers, however, and in a few years are as abun- 

 dant as before. I am not aware that they ever migrate except when 

 exceedingly abundant. Of these immense hordes but few probably sur- 

 vive. No sudden increase in their numbers was heard of in southern 

 Wisconsin after the several migrations from northern Illinois. Many 

 are drowned in attempting to cross streams; not a few are destroyed by 

 man ; some die from utter exhaustion, and when forced to travel in an 

 unnatural manner, upon the ground, they fall an easy prey to rapacious 

 birds and mammals, all of which feast when the squirrels migrate." 



I learn from Dr. Hoy that one of these migrations is said to have 

 taken place in 1842 ; he witnessed another in 1847, and a third in 1852. 

 From these facts, and from observations made in Ohio and elsewhere, he 

 is of the opinion that the migrations, in most cases at least, occur at 

 intervals of five years; and if he be right, the squirrels, which are now 

 exceedingly abundant again in southern Wisconsin, may be expected to 

 migrate in the autumn of 1867.* He further says that the migrations 

 observed by him in southern Wisconsin occurred when the mast was 

 exceedingly abundant and the squirrels in good condition. Near Racine 

 they were observed passing southward in very large numbers for about 

 two weeks, at the end of September and the beginning of October, and 

 it was a month before all had passed. They moved along rather leis- 

 urely, stopping to feed in the fields, and upon the abundant nuts and 

 acorns of the forests. So far had they departed from their acciistomed 

 habits that they were seen on the prairie, four or five miles from any 

 timber ; but even there, as usual, they disliked to travel on the ground 

 and ran along the fences wherever it was possible. 



* Since writing the above I have received the following letter from Dr. Hoy : 



Racine, Ajpril 2, 1878. 

 Dbab Sir : Black and gray squirrels did migrate in 1857, as predicted. Whether 

 there is a precise interval between their migrations I wiU not pretend to state, yet they 

 did migrate in this section in 1847, 1852, and 1857, since whieh they have become so 

 scarce that I conld not determine whether there was an attempt to migrate or not, as 

 they are nearly exterminated now in this vicinity. In 1857 I knew one negro who stood 

 by a tree, in an open space on the line of a fence, and shot over twenty in one after- 

 noon. In other years one might stand at the same place six months and not see one 

 individual. Tonrs, p. K. Hot. 



