208 ROLAND F. HUSSEY 



left the nest. By far the greater part of the summer's work 

 was done on these hermit thrushes, because the nest was easily 

 accessible from the Station, and because the hermit thrush 

 proved a good subject for experiments of this sort. 



Another nest, that of a robin, was discovered some days later, 

 within the limits of the camp. Although for more than two 

 weeks efforts were made to test the auditory reactions of this 

 bird, it was found to be too timid for practicable experiments. 



In .addition some work was done in connection with this 

 problem on birds found in the field, particularly on some of 

 the birds characteristic of the cedar bog, and with some shore 

 birds. Experiments were also made upon some young cedar 

 waxwings which had been taken from their nest and placed 

 in a cage for special study ; but by the time that my experiments 

 were begun the waxwings had become so accustomed to the 

 presence of various people and to noises of all sorts that no 

 positive results could be obtained. 



II. METHODS AND MATERIALS 



The experiments with the nesting hermit thrush were for the 

 most part made with the aid of a small white observation tent 

 which was pitched so that the apertures for observation were 

 within six feet of the nest; and a narrow path from these aper- 

 tures to the nest was cleared of grasses, etc., so as to admit 

 the making of photographs. The tent was first pitched on the 

 morning of July 10, and it was taken down the same day; on 

 July 12 it was replaced and was left standing until all the work 

 possible on the hermit thrushes had been completed. 



The observations on the birds of the cedar bog and on the 

 other birds experimented with in the open field were made 

 without the use of any special shelter. Great care was taken 

 to avoid other than auditory stimulation. 



The sounds used were made as varied in character as possible. 

 Those tried on the hermit thrush included shouting, singing, 

 whistling both with the lips and with a " double-tone " metal 

 whistle, chirping with the lips, clapping the hands, rapping on 

 wood and on metal, and rustling papers and birch-bark. To 

 test the reactions to sounds of different pitch a mandolin was* 

 used. The same sounds were also used in the case of the other 

 birds, but such as involved sudden movement, as clapping the 

 hands or rapping on wood or on metal, were not tried to any 



