Page:American Journal of Psychology Volume 21.djvu/44

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34
PORTER

161. In fact it was this change which introduced sufficient delay to make it possible for the young Song Sparrow to open the door. She did not, so far as could be seen, do so in an imitative way. Later there were a few movements which were similar to those of the White-throated Sparrow, but they did not have to do with the right part of the box.

Fig. 14

This shows the method which the White-throated Sparrow used to open the door. She often was compelled to make many efforts because she alighted on the post rather than the outer end of String B.

Table VI

The Junco of series D, a Field Sparrow, a White-throated Sparrow and a male English Sparrow. Results of tests with the food-box.