24S Papers from the Marine Biological Laboratory at Tortugas. 



maze as a whole was 4 feet square ; the aheys were constructed of white 

 bristol board and were made 5 inches high and 5 inches wide. The top 

 was covered with 0.375-inch wire mesh. The bottom of the maze was of 

 wood. In order to determine more accurately the number of useless move- 

 ments, fine white coral sand was sifted over the bottom of the maze to a 

 depth of 0.25 inch.' The movements of the birds could be traced com- 

 pletely by the tracks which they left in the sand. By means of a small whisk 

 broom these tracks were obliterated after each trial. 



It will be seen that the maze offers both a long and a short way to O. 

 A few of the birds learned the maze at first by the long way ; all adopted the 

 shorter waj' before the experiment was over. 



The maze was placed in a large room, which was well lighted by 2 win- 

 dows, one to the west of the maze, the other to the north. 



Since the birds were perfectly habituated to handling they were placed by 

 hand at H and their time in reaching O, together with the number of errors 

 made, were recorded by me. Thinking that my presence might influence the 

 reactions of so keen-sighted a bird, I watched their reactions through a small 

 auger-hole bored through the south wall of the room. 



Two trials per day were given, one at the morning feeding and one 6 

 hours later at the noon feeding. The birds were allowed fully to satisfy 

 their hunger after each successful trial in the maze. The night feeding was 

 not made in connection with the maze, but in the large experimental cage 

 which remained out in the open. Four sooties, of which 3 were males, and 

 3 male noddies learned this maze. 



THE BEHAVIOR OF THE SOOTIES IN LEARNING A MAZE. 



I began feeding the sooties in the maze by blocking off the runway G from 

 the rest of the maze and by closing the entrance to 5". The cover of the 

 maze was raised and the bird was then put down in this runway and allowed 

 to come out at and walk up the inclincil platform to the food which was 

 contained in a dish resting upon a box 8 inches high.^ Two feedings were 

 sufficient to accustom them completely to this situation, but since the noddies 

 were not sufficiently developed to begin work upon the maze, I fed the sooties 

 in this way for 7 days. 



The sooties began learning the maze properly when they were 15 days 

 of age. At this age they are as fully developed, so far as coordination of 

 movement is concerned, as the noddy at 19 days. 



Table 3 and the graph (fig. 3) constructed from it show the time-records 

 and the general features of the learning process. 



' This method is fully as accurate and far more cleanly than that of using smoked 

 paper. 



" See p. 244 for tests on learning to walk up an inclined plane to the top of a box. 

 The same plane and box used there were employed in this connection. 



