1174 A live mouse, smaller than the rat, was then given him. There was no display with this either, though he carried it about for some time, finally gobbling it. Next in order was sunning and preening. During the latter operation the first tail-feather of the season was removed: one of the two middle rectrices. It was measured and found exactly 12¾ inches long from tip to tip. (324 mm.) It is ¾ of an inch longer than the feather from the same place last year. (19mm.) Its coloration is essentially the same basically, but it is decidedly darker, with far less coppery-metallic reflections. Though both feathers are worn somewhat at the tip, it looks as if this year's feather were longer when perfect. Rhody next wandered off to the west of the house. His attention being attracted by some pine needles, he gathered them up, went to the mirror about 75 yards away, where he showed them to his reflection briefly, then took them to 2-36. Now this place has pine-needles all over it. They can be found anywhere near the nest also, with no necessity for carrying them such long distances. It would seem that this action of his is purely instinctive and when the impulse to build seizes him he simply has to obey, no matter where he may be. It is curious, also, that he utterly ignores the mirror except when he has food in his bill, or nesting material. The fact that he makes but a short stay at the mirror, a few seconds at a time, suggests that he has some sort of a dim realization that no practical result can follow from his display before it. At about 1:30 P.M. he was given a small, live house-mouse. The usual behavior followed, including a visit of about 30 seconds to the mirror. At the mirror his tail wagging and bowing always become intensified. This mouse was taken to nest 1-36. About 5 P.M. Rhody was given another similar mouse, with the same results, except that, this time, he took it to nest 2-36 after visiting the mirror. I had thought that this nest had been forgotten. Certainly it is not highly favored, for he soon left it and took the mouse to 2-36 finally after much hesitation, due to the exceptionally noisy operations on the house at the moment. April 30th. I saw and heard nothing of Rhody until about 9:15 A.M. when I went to nest 2-36 to see if he was there. As I approached his whine was heard coming from it. As I stood below it, he came to life and began to rearrange twigs inside. At 9:30 he came to the cage for a session with the magpies, leaving shortly to go to nest 2-36. Again he stayed for but a short time, then began to climb about inside the tree. He found a new towhee nest. (I had found it myself 3 days ago). He examined it inside, deliberately walked across it and came down. Next a twig attracted his attention. This he carried to the mirror and pressed against the glass repeatedly without display. Next in order was to take it to 2-36; but instead he took it up into 4-36, returning to watch the magpies some more and loaf about to see what I was going to do about mice and rats, since he had had none this morning. I wanted to get a colored movie of him displaying with a mouse and made the necessary arrangements. Instead of doing his part as was to be expected, he gobbled the mouse without performing any