sparrow-hawk flew overhead with its loud clee, clee, clee, and all the birds sought cover, except R who was momentarily startled, but recovered instantly and began preening. The birds do not regard him as they do a hawk, even a sparrow-hawk. Rhody in going through the brush is almost absolutely noiseless; by far the most silent of all the birds here. I can usually hear B or any of the other birds approaching me; but R is a ghost. This morning I watched him hunting (a very leisurely process for him) outside the western fence (his usual morning territory) and about 75 feet away. I tried to attract him, but he would not come, so busied myself with training a vine on the fence--not a noisy job-- in fact a silent one. I happened to look through the fence and there was R 3 feet away looking at me, not having made a sound coming through the brush and dry grass. He opened his mouth wide enough to emit a roar, but only the smallest sort of a whine issued. (One of his few characteristic vocal sounds). He was pleased to poke his bill through the wire mesh to take worms from my fingers as long as they were offered and waited patiently for more after I got tired of giving them to him. I set the mirror again for him near the cage entrance; this time not quite horizontally placed, so that he would be sure to see himself if he passed within say three inches of it. When he came he saw him- sself at once, but, although he pecked his reflection, he did not get excited, and was far more interested in the meat and the birds in the other compartments of the cage. Thus it appears that the intensity of his excitement is a function of the angle at which the mirror is displaced from the horizontal! Zero when horizontal, maximum when vertical. Tentatively: I = f(sinφ) Where I equals the intensity and φ is the angle with the horizon- tal!