494 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
fair guess would be to suggest that we had here an incipient alarm 
cry which did not involve a stimulus strong enough to produce the 
full response. 
Young herring gulls give a ery for food which varies with age. The 
newly hatched birds utter only weak peeps. As they grow older these 
develop into more insistent squealing notes which may be made with 
a bowing motion for each. When attacked or in distress, juvenal 
gulls often make a sharp and still more incisive squeal in which the 
notes are uttered more rapidly and more loudly. I have already 
mentioned the attempts at a challenge cry which are made by 
juvenals. 
VIII. REACTIONS TO STIMULI. 
1. Auditory.—I know of no experimental work on the reactions of 
gulls to sound stimuli, but I have made numerous observations in 
the field and with my captive gulls which show that hearing is rea- 
sonably keen in these birds, especially under certain circumstances. 
The bird shown in plate 5, figure 2, was easily startled during the 
earlier part of my tent studies by the small though sharp noises made 
by the shutters of my cameras. During the course of the day this 
gull became less and less sensitive to such noises and to other slight 
sounds which came from my tent, though one end of the tent was 
hardly 5 feet away. The responses finally consisted of little more 
than short turns of the head. A pistol shot from a boat fully a quar- 
ter mile away from shore caused a wild panic on the island. Little 
attention had been given to the boat before the shot was fired and 
boats could come nearer without causing a disturbance so long as no 
shooting occurred. 
On another occasion the sharp noise made by a falling timber on 
the beach caused great alarm among gulls which could hardly have 
seen the fall. Great excitement was caused during the night of my 
stay on one of the Strawberry Islands by the noise produced by a 
falling board which was blown down from a position against my 
tent. It is improbable that many gulls if any could have seen this 
board fall. The resemblance of such noises to that made by the 
firing of a gun undoubtedly explains the intensity of the reactions. 
Many and perhaps all of the adult gulls had learned the significance 
of a gun shot. 
My captive gulls when tested by some simple experiments on Sep- 
tember 27 and 29, 1913, were not much disturbed by any noises which 
I made out of their sight, though they responded to various sharp 
sounds or to a sudden shrill whistle by quick turns of the head. 
2. Visual reactions.—Like practically almost all birds the her- 
ring gull is predominantly visual in its behavior. It also appears to 
be unusually alert to visual stimuli. Rapid movements. especially, 
