MAMMALS OF MINNESOTA. 203 



domestic cats and other enemies. In such places their nests 

 may be found in almost every suitable grass tussock, and under 

 fallen trees or driftwood. Such islands are, of course, flooded 

 during a short period in spring, and these freshets are times of 

 great excitement among the mice which have domiciled them- 

 selves under the boards and riffraff left by the last flood. 



In April, 1885, while in camp upon a large low island at the 

 head of lake Pepin, a hard storm of rain and snow caused a 

 sudden rise in the river of nearly fifteen inches sufficient, at 

 least, to flood the greater part of the island and float away 

 many traps set for mice and shrews in various places. Near 

 the tent was a broad bay the low shores of which, for acres in 

 extent, were covered with driftwood, which furnished conceal- 

 ment for innumerable mice, Arvicola riparius. When the river 

 began to rise the water oozed beneath the boards, and before 

 the observer was really aware of the encroachment of the 

 waters the whole area was afloat. 



The night was clear and moonlit, and as we stood watching 

 the most insidious approach of the waters, wondering if we 

 should be compelled to remove our camp, we were astonished 

 by a confused rustle and murmur not unlike that produced by 

 the wind among dry leaves. This we were at a loss to account 

 for since the night was perfectly still. At our feet, however, 

 something tangible appeared in the shape of a group of mice 

 fleeing from the waters, creeping out from their hiding places, 

 in evident alarm, which was expressed in querulous cries as 

 well as by their excited and uncertain movements. To use a 

 common expression, the whole tract was "alive" with mice 

 fleeing for their lives toward the higher open ground behind. 

 The picture was that of the Ohio floods, with mice rather than 

 men as actors, and furnished an illustration apropos of Burns's 

 lines, " The best laid schemes of mice and men gang aft agley." 

 A pair of great-horned owls, whose nest was hard by may have 

 profited more by this unexpected hegira than the naturalists of 

 the party but, presumably, were less affected by its novelty 

 than they. 



Arvicoia riparius var. borealis RICH. 



It is interesting to compare a specimen of Arvicola sent us by 

 Prof.W.W. Cooke, of Moorhead, Minnesota, with the measure- 

 ments and the description of the arctic form called borealis by 

 Richardson. This specimen, collected March 15th, 1885, 



