342 Life-histories of Northern Animals 



the woodland. Foreseeing that the nut crop will fail (this being 

 the even year), they commonly emigrate in July and do not 

 again appear till September or October of the ensuing year. 



" Briefly, then (leaving out of consideration the small 

 number of resident individuals, and the migrants that some- 

 times pass through on their way to distant parts), we find 

 Chipmunks reach the Adirondack region during September and 

 October of the odd years (nut years), remaining till the follow- 

 ing July. They then depart and are not seen again till the 

 autumn of the next year. Hence they are here about ten 

 months and absent about fourteen months, the period of 

 greatest abundance being in June of the even years (when 

 there are no nuts)." 



I do not find in this conclusive proof that the species is 

 migratory. I cannot learn that any one ever saw a migration 

 of Chipmunks. Nor are they known to appear in unusual 

 numbers elsewhere in the season in question. One or other 

 of these facts seems to me necessary to support the theory of 

 migration.^ 



At Cos Cob, Conn., the Chipmunks had abounded up to 

 the autumn of 1907. The nut crop was a failure that year. 

 In the spring of 1908 a melancholy change had come over the 

 woods. There was no spring chorus and only three Chipmunks 

 were discovered after a thorough investigation covering weeks. 

 All three were at places where they could live on corn put out 

 for the ducks. In June there seemed to be a slight increase in 

 the number of adult Chipmunks, which added a perplexity to 

 the problem. But I am still inclined to think that the increased 

 numbers of Chipmunks in the Adirondacks during nut years 

 is, that the plentiful food supply permits actual increase, and 

 in famine years they die. They seem most abundant in June 

 of the nutless years, because the scarcity of food compels them 

 to be out and stirring all the time, and so they are much in 

 evidence. 



^ Since the above was written John Burroughs writes me that in the summer of 1908 

 the Chipmunks appeared at Roxbur)', N. Y., in extraordinary numbers. So the question 

 remains open. 



