(15) So far I have only guessed at the sexes. "His" eyes appear to be different in color from his mates. Hers are brown with a bright orange tinge; his are brown with a greenish-slaty tinge, i.e. cold, while hers are warm. If this difference in the eyes is correct, and I have no reason to doubt it, it is the only constant difference I have been able to detect between these two birds as yet. February 24th. I went to the nest at 8:30 A.M.; the "female" was sitting in it with only her head and tail showing, doing nothing. I said to her in an ordinary conversational tone: "Hullo, Mrs.", without indicating in any way that I might have something for her to eat. She immediately popped out of the nest and came trotting over to me, looking up at me inquiringly. I then sat on my heels and put one meal-worm after another in the palm of my hand for her. While eating these she noticed that the top of a soap-root bulb was showing above the ground and began to tear the fibrous coating off of it and carried it to the nest. In the meantime the other bird had poked his head up over the bank about 3 feet from my hand, and, seeing what was going on, came forward eagerly to join his mate, but suddenly remembered that his dignity would be compromised, or something, so paused. I tossed him a worm which happened to land in amongst some rope yarn that I had placed there, thus inadvertently calling his attention to the yarn. To get the worm he had to reach into the yarn and in this way a few fibres got into his bill. He swallowed the worm and then hesitated about what disposition to make of the fibre. He had seen it many times before and had as often rejected it, also there were worms to be had without effort. There can be little doubt that the general configuration of things, as judged by his actions, puzzled him. I would like to think that he reasoned about it; perhaps he did. In any case, the dilemma was solved by his taking the rope up to the nest