230 Papers from the Marine Biological Laboratory at Tortiigas. 



in the morning of the following day. The noddies were observed on their 

 nests at 7 a.m., while the sooties were noted for the first time at 6" 30" 

 p. m., of the same day. 



The distance in a straight line from Havana to Bird Key is approxi- 

 mately 173.8 km. (108 statute miles). 



I think that these tests are significant. The return from Cape Hatteras is 

 really startling. Cape Hatteras is hundreds of miles outside the range of 

 distribution of the noddy and sooty terns, li my statement that the birds 

 rarely leave the island for distances greater than 15 knots for purposes of 

 feeding corresponds with the facts, it becomes e.xtremely improbable that they 

 could have formed visual associations throughout such a vast territory as that 

 described in these experiments. While these experiments are not in any way 

 crucial, the facts obtained from them are e.xtremely difficult for current 

 theories of distant orientation to explain.' 



SOME PRELIMIXARY EXPERIMENTS WITH SOOTIES UPOX THE 

 LE.ARNING OF PROBLEM BOXES. 



In all the following experiments, small wire boxes were put down over 

 the egg and the bird was forced to overcome certain difficulties before it 

 could reach the egg. The experiments will show that this method could have 

 been used with profit if time had permitted. On account of the difficulty 

 of making suitable problem boxes, our experiments are of a very rough and 

 ready kind. 



Experiment I. 



A simple labyrinth was placed over a sooty nest. This labyrinth oiifered 

 only one blind alley, but the bird was forced to change its direction three 

 times and traverse a distance of about 3 feet before it reached its egg. 



The movements of the sooty when this situation confronts it are char- 

 acteristic. It first takes up a position which offers the plainest view of the 

 egg and then attempts to push its head straight through the meshes of the 

 wire. Leaving this position, it walks around and around the labyrinth as 

 a whole and makes no attempt to enter the open door, although the latter 

 is made very prominent by virtue of its being marked with two large up- 

 right sticks. The first four or five trials consumed about an hour each, 

 the birds working persistently most of the time. So little improvement 

 was manifested and the test bade fair to consume so much time that I 

 abandoned taking continuous notes upon it. I left the simple labyrinth in 

 place, however. By the end of 3 days, bodi male and female had adjusted 

 themselves perfectly to it and could go in and out with rapidity, but when 



'When I left the island I carried a noddy to a distance of 40 miles in order to 

 ohserve its behavior during the trip. The bird was turning in a circle, twisting, and 

 poking at the mesh of the wire cage incessantly. The turns and movements of the 

 vessel did not influence the movements of the bird in the least, so far as I could 

 observe. When released the bird i^ew down near the surface of the water and started 

 in the direction of home. Dr. Mayer informed me that this bird returned to its nest. 

 Reynaud's law of " contre-pied " has in my opinion not the slightest basis in fact. In 

 order to duplicate in reverse order on its return all the movements made on the out- 

 going trip the bird would have had to fly back, revolving mainly in a circle ! 



