Page:American Journal of Psychology Volume 21.djvu/66

56 he began to make after the box had been in about two hours, he opened the box by pulling the second string with his beak. Most of his trials were pecks on the wire eyelets by which the strings were attached to the post at the right corner. It was most amusing to see him peck at these and the wire and then in a savage manner pull up great bunches of grass. After the door was opened seven minutes were required for him to take a bit of food from the pan just inside the door.

On the 2d test seven minutes were required and twenty-nine efforts. The 3rd and 4th tests were failures for the reason, largely, that he was not hungry enough. The cause of this was that he had stolen a rat from the caretaker while the latter was feeding the Sparrow-hawk.

From the accompanying table (XII) it may be seen that this Crow like the other birds learned rapidly once he began. He was given more trials per day than most of the others. His many efforts were perhaps due to the fact that his fright caused him to attempt to strike when he was too far off to do so accurately. On the 2oth test he returned to the perch at once on opening the door. Almost immediately he returned to pull the first string some nine times and this with the door already open. On the preceding day he did this once as I started to remove the box from the cage. On the following day, July 3oth, he did it four times during one trial. On July 3ist,

Results of experiments on three Crows with a Food-box similar to that used in all the Previous Series.