A STUDY OF COLOR VISION IN THE RING-DOVE 29 



numbers 1 and 2 will be' presented only in contrast with those 

 of numbers 3 and 4, since the conditions of use varied some- 

 what, and the experiments conducted by Mr. Eisenberg were 

 not carried so far as those of the writer. The descriptions of 

 general behavior in this paper will be based almost wholly upon 

 the observations made on doves 3 and 4. 



At the outset, it was assumed that the ring-dove would react 

 satisfactorily in the discrimination apparatus, that it would 

 exhibit a fair degree of docility, breed rapidly in captivity, be 

 easy to handle, and endure close confinement well. It must 

 be admitted that these assumptions have not all been justified, 

 for the birds did not quickly adapt themselves to the experi- 

 mental situations, and in docility they rank low. Indeed, their 

 slowness in acquiring the discrimination habit demanded in this 

 work was a great surprise to the writer. He is now somewhat 

 uncertain as to whether it is desirable to attempt an intensive 

 study of visual response with a subject which demands such a 

 large amount of training. 



Work was initiated by feeding the birds in the entrance cham- 

 ber of the experiment-box, with all of the doors of the box open 

 so that the subject might wander about at will. This was con- 

 tinued for a week, with the occasional variation of opening and 

 closing the doors as the bird passed from compartment to com- 

 partment, so that it might become accustomed to the operating 

 of the simple mechanisms and learn the route from the entrance 

 chamber, by way of the stimulus chamber, back to the starting 

 point. 



During the second week of the preliminary observations, the 

 birds were sufficiently tame and accustomed to the apparatus 

 to work fairly well. They were regularly each morning required 

 to make the trip through the apparatus three or four times, 

 and they were rewarded for so doing with food. It was dis- 

 covered that they would not make the trip quickly unless they 

 were very hungry, and even in that condition their attention 

 to the situation was very variable, and they were so easily 

 distracted by slight noises or jars that the whole process was a 

 very tedious one. It thus became apparent that unless an 

 additional motive for discrimination and progress through the 

 experiment-box could be discovered, the work would be most 

 tedious. Consequently, at the beginning of the third week, 



