length from 6 inches to 2 feet. All were taken from the ground. Most had to be pulled out from the ground or from tangles of detritus under the trees. In the time intervals shown they had to be found, selected, pulled away from attachments and entangle- ments, carried along the ground from 10 to 40 feet, surmounting elevations offrom 0 to 10 feet before reaching the level of the tree base. Thence they had to be carried by flight and climbing up through the interior of the tree by a zig zag course rising about 20 feet vertically and covering perhaps the same amount horizontally. (This is a high nest for a roadrunner). They also had to be forced through obstructing branchlets and each definite- ly placed in the structure and the bird had then to descend, sometimes by climbing higher to get a good take-off, and sometimes climbing part way down, then sailing the rest of the way. There were times when he was unable to free twigs from their surroundings, and others when he tried unsuccessfully to detach twigs from the growing plant,or tree in which the nest itself is. Further, occasionally Rhody had to "rattle-boo" from the nest and look down at me and whine. Notwithstanding these irregularities and distractions his goings and comings were surprisingly regular. (11:16. I will suspend note writing and see what Rhody is doing......11:19: He is still working on No.5, having just extracted a twig from the rhododendron mulching 10 feet from me without appearing even to notice my presence). Continuing the table of observations: 22 in 49½ min. (This longer interval because I went and talked to him, while ob- serving progress). 23 " 51¼ " 24 " 54 " 25 " 57 " (He is now looking for finer material and rejecting coarse). ( He has to look more carefully and discover its location. As he came near me I picked up some fine Baccharis twigs and said: "This is the kind of stuff you need now for a binder." He was trying to pull rootlets of broom from the growing plant--an impossible task. He took the baccharis from me and headed for the tree with it. Something was not just right about it, so he dropped it and found something better: 26 in 62½ min. (Showing time lost). 27 " 65 " (He has to go down to the road for this). 28 " 67½ " 29 " 69 " (He has gone back to coarse). 30 " 71 " Observation period ended here, although he kept on working. The showing made on the nest itself in this time was surprisingly insignificant considering the really tremendous effort. Roughly, it will be seen that he placed a twig about every 2 minutes, notwithstanding the amount of work involved. In an hour he climbed about 5 or 600 feet vertically and traversed perhaps a quarter of a mile horizontally--all of the vertical height under load. Besides this was all the effort of overcoming resistances of various kinds--a no inconsiderable task. There was no rest at all. Considering that this is the fifth unproductive nest of the year so far--and he has really made almost no physical progress on it--and assuming that all this effort is directed by instinct, unguided by reason, it would appear that instinct alone can be a pretty uncomfortable thing to be burdened with! 11:55, Well, Rhody is now resting quietly in his new nest.