not due to the fact that it is more hardy than other birds. When placed in the larger one of my cages with a pair of English Sparrows and Cowbirds, the Junco spent the time during the first tests running back and forth on one of the window sills.
The male Cowbird opened the door during the first trial of this series in a purely accidental way. In the second trial the male Sparrow was successful. He did it in much the same way as the male of this same species who has figured in the earlier series A and B. His fright seemed to induce him to use this method of flying up and out and seizing the string without alighting. In the third and fourth tests the female Sparrow was successful by hopping up on one of the strings. In the fifth the Junco succeeded by striking the string with one wing as it chased the female Sparrow away from the front of the box. A great change had come in the Junco's behavior after the first trial and previous to the fourth. It chased the female Sparrow away at every opportunity, but was in turn no match for the male Sparrow. It was evident that the female Sparrow wanted to open the door. The female Cowbird remained outside the box when the Junco was on the inside.
In the sixth test the male Sparrow made an effort. The Junco chased the female Sparrow away several times. The latter was induced to run round the box several times by following the male Sparrow. Finally the female Sparrow opened
_Fig_12.jpg)
Fig. 12
The first method used by the Junco in opening the door. She must make many hops to this spot for the reason that her claws do not strike string B. The Cowbird is looking for parasites on the male English Sparrow.
