THE BEHAVIOR OF THE CROW 187 



his hand. This friendliness was shown to no other person, and 

 an entire stranger would frighten them very much. 



Four other crows were obtained from Pennsylvania, but they 

 were too wild for use in the investigation. 



The building, in which the experimenting was done, was 

 divided into two compartments, each 10 feet by 12 feet. One 

 of these served as a roost and feed-room. Adjoining this room 

 was a fly, 24 by 10 by 8 feet high, made of chicken wire. The 

 crows could fly direct from the roost to a perch in the far end 

 of the fly. 



The other compartment, which served as an experiment- 

 room, was set off from the feed-room by a partition of chicken 

 wire and a burlap curtain. The curtain could be pulled aside 

 when experiments were not in progress, thus allowing a free 

 circulation of air. 



The apparatus used was a modified form of the discrimina- 

 tion-box used by F. S. Breed » and later by L. W. Cole « in 

 their studies of the reactions of chicks to visual stimuli. The 

 following description is intended to give only the essential points 

 of the apparatus. For a more detailed account, reference may 

 be made to the reports of Breed and Cole. 



The entrance-chamber was a movable box 18 by 16 by 14 

 inches deep. The top, bottom, and three sides were of one-half 

 inch boards. The fourth side was covered with wire netting, 

 one-fourth inch mesh. In each end were openings, 7 inches by 

 9 inches, with horizontal slide doors. 



Leaving the entrance-box, the crow entered the discrimina- 

 tion-chamber. This was 16 by 19 by 13 inches deep. The top 

 was of wire, one-fourth inch mesh. Opening directly into this 

 chamber were two chambers, 18 by 19 by 13 inches deep. The 

 tops of these chambers were of wood as were also the sides and 

 floors. The exit from each of these chambers was 7 inches by 

 9 inches, with horizontal slide doors. They opened directly 

 into two exit -boxes similar to the entrance-box. The front ends 

 of the stimulus-chambers were formed by a three-stimulus 

 plate-shifter sliding in wooden tracks. For a minute descrip- 

 tion of this shifter, the reader is referred to the papers of Breed 



3 Breed, F. S. Reactions of Chicks to Optical Stimuli. Jour, of Animal Be- 

 havior, 1912, vol. 2, pp. 280-295 



* Cole, L. W. The Relation of Strength of Stimulus to Rate of Learning in the 

 Chick. Jour, of Animal Behavior, 1911, vol. 1, pp. 111-124. 



