NATURAL HISTORY OF AMIA CALVA LINNAEUS. 83 



often exposed to bright sunlight (see photographs by Dean, '98), while at other 

 times he lies concealed in the natural openings of the adjacent vegetation. I have 

 never observed that he removes any vegetation or that he in any other way pre- 

 pares a "run" or "bed" for himself. In order to approach the nest one may wade 

 or use a boat, best a flat-bottomed punt propelled by a paddle. For the purpose 

 of finding nests wading permits of more careful examination, but for subsequent 

 visits the boat is to be preferred wherever practicable. In both cases great care 

 must be taken not to cause any sudden disturbance of the water. In wading one 

 must move very deliberately, often as slowly as possible, and must be certain that 

 the forward foot is on firm bottom before taking the next step. In lifting the feet 

 from the water they should be brought out slowly and toe down so as to permit 

 the water to run from the boot as gently as possible. In this way, if no false step 

 has been made, one may usually come directly over the nest without disturbing 

 the male, unless one has happened to come upon him unawares in his hiding-place 

 near the nest. If the fish is not visible or not wholly visible as one stands over the 

 nest, the vegetation which covers him may be gently and very slowly pulled to one 

 side and the fish fully exposed. This I have done often, and in one case, after having 

 exposed the fish and nest in this way to a flood of sunlight, I was able to set up a 

 camera on a tripod directly against the nest and to spend half an hour in attempting 

 to photograph the fish, and all this without causing him to move farther than from 

 one side of the nest to the other. The fish do not react to the visual image of 

 the observer, but to sudden movment whether of the water itself or of the objects 

 outside the water and independent of it. It is therefore only necessary to move 

 slowly enough and without mechanical shock to the water to attain any desired 

 position with reference to the fish. 



As the observer approaches the male may move toward him, but not usually 

 beyond the limits of the nest. If frightened, the male goes off with so much rapidity 

 as to leave a wake behind him. I have not observed that at this time he splashes 

 with his tail above water as he does later when attending the swarm of young. 

 After a time the male may be seen to return slowly and quietly to the nest, and if 

 one has waited one may then watch him for any length of time. Males on empty 

 nests take fright much more readily than those on nests containing eggs, and from 

 such nests it is usually not possible to remove the floating vegetation without dis- 

 turbing the fish, whose senses are then doubtless all alert in expectation of the 

 approach of the female. That the male does not stand guard continuously over the 

 nest is shown by the fact that at many visits he is not found in spite of careful 

 search through all the surroundings. 



