A STUDY OF THE REACTIONS OF CERTAIN 

 BIRDS TO SOUND STIMULI 



ROLAND F. HUSSEY 



I. INTRODUCTION 



This problem was undertaken at the Biological Station of 

 the University of Michigan, under the direction of Professor 

 R. M. Strong, between the dates of July 10 and August 21, 

 1916. 



The Biological Station is located on Douglas Lake, in the 

 western part of Cheboygan County, Michigan. The region 

 immediately about the camp is covered with a fairly dense stand 

 of young aspens, birches, and pin cherries, with occasional oaks 

 and maples. This is the type of vegetation which has succeeded 

 the original forests of pines and hardwoods in this cut-over 

 and burned-over country. A few pines remain, chiefly along 

 the lake shore, but there are no hardwoods in the immediate 

 vicinity of the Station. Another important type of vegetation 

 is found in the dense cedar bogs, where " arbor vitae, balsam, 

 tamarack, and spruce form a nearly impenetrable jungle." 



The bird life naturally shows a marked ecological concentra- 

 tion of species in these widely different habitats. In order 

 that observations on any species might be made as nearly contin- 

 uous as was desired, it was thought best to work with nesting 

 birds as far as possible; and accordingly on July 5 search was 

 begun for suitable subjects. But although birds are really 

 fairly plentiful in the aspens during the early summer, the 

 abundance of nesting sites furnished by so extensive and so 

 uniform a habitat as the aspen association made the discovery 

 of nests very difficult. In fact, it was not until the morning 

 of July 8 that a nest was found located so that work could 

 successfully be carried on. 



The nest referred to was that of a hermit thrush. It was 



placed on the ground in a small cluster of oak seedlings, about 



a hundred feet from the shore of Douglas Lake. Work was 



begun here on July 10, and was continued until the young birds 



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