(49) disposition to take over operations, so I gave him a worm or two to see if he would take them to his mate and then change places. But he ate them all himself, so I returned to the nest. Brown-eyes was peering about and occasionally craning her neck over the rim of the nest, evidently looking for her mate, who by this time was prod- ding about the base of the tree. B.E. called down to him with a short, low, throaty chirp of about the same pitch and timbre as the call of the Western Blue-bird. G.E. came up at once an/took charge. There was no appearance of haste or impatience on the part of either bird, both acting calmly and in matter of fact manner. At 11:20 B.E. came through the fence below the glade where I stood, eager for food. I rested my hand on a piece of bark an inch or so thick, to hold it steady. I usually rest it on the ground. Brown-eyes had to look into this unaccustomed procedure and thrust her head underneath my hand as if to see what was holding it up, then resumed eating and, when finished, relieved G.E. promptly. G.E. went directly to the oval lawn where there is always a sup- ply of food, but I gave him worms too. It looks as if an important factor determining the length of a watch is the time required for the bird off duty to get a good meal. If this time is too long in the opinion of the bird on the nest, it appears from at least one instance noted, that that bird gives the signal for the change to be made; but there is no certainty of this. At 5 o'clock I thought I would see if I could cause them to change by trying to entice away the bird that was on duty. I had not been there for several hours. Brown-eyes was on the nest and much inter- ested in the worm that I held about 4 feet away. She was strongly tempted, but did not yield. As G.E. was down in the glade, I got him to come for worms about 8 feet from the nest. This was too much for Brown-eyes. She called once, but as her mate stubbornly refused to relieve her, she popped out of the nest anyway and came to eat out of