212 ROLAND F. HUSSEY 



or loudness of sound. After the bird had become accustomed 

 to the mandolin and to the whistle so as to react to them only 

 slightly, I tried the effect of interrupting the mandolin chords 

 by loucf whistle blasts, and found that the bird reacted markedly, 

 though with decreasing vigor as the experiment was repeated. 



I experimented also on the combination of auditory with 

 moving visual stimuli. As stated above, the sudden appearance 

 of my finger at the aperture seemed to startle the bird, but the 

 reaction decreased rapidly in vigor on successive trials. The 

 same was true of the reaction produced by sounding the open 

 G-string of the mandolin. If, however, I showed my finger 

 at the aperture, then, after a short pause, moved it suddenly 

 and at the same instant sounded the G-string loudly, the bird 

 reacted vigorously; and the reaction was as strong at the thirtieth 

 trial as at the first. 



July 13, 8:45-10:20 a. m., 1:10-3:20 p. m. The work in the 

 morning was similar to that of the two days previous, and the 

 reactions observed were similar, though less vigorous on the 

 w T hole. The combination of auditory and visual stimuli was 

 tried again, and the same results were obtained by combining 

 the movement of my finger with a loud whistle blast as with 

 a mandolin sound; although fifteen trials were made, there was 

 little, if any, diminution in the vigor of the reaction, which in 

 this case consisted usually in turning the head and closing the 

 bill momentarily. 



In the afternoon I approached the nest from the side opposite 

 the tent. I crept up over a thick growth of bear-berries without 

 taking particular pains to move quietly, so that I am sure that 

 the bird must have heard me. The bear-berries screened me 

 from the nest, so that until I came within three feet of it I 

 could not see the brooding bird. I found that the bird seemed 

 not at all on the alert for any disturbing sound from the tent, 

 nor had it seemed to notice my approach. I then blew a loud 

 blast on the whistle, but it showed no sign of fright, and merely 

 turned its head slowly until it caught sight of me, when it 

 immediately left the nest. 



I then concealed my watch carefully about six inches from 

 the nest, and immediately entered my tent. When, after fifteen 

 minutes, the bird returned, it was very plainly made uneasy 

 by the ticking of the watch; it turned its head from side to 



