FAP 1961 Calypte anna April 15 Berkeley, California and remained perched a few moments. He then perched, and sang strongly, directing his head toward the center of the pear trees. The circling flights were clearly efforts to locate [illegible] sound or [possibly chip-notes] of the hummer to which the dives were addressed. The first circle was mostly, if not entirely a glide, giving the male a better chance, presumably, to relocate the intruder. This behavior seems to grade into what I have called the circle display, with the male singing from successive points along a circumference, always directing his song to the center of the circle. On today's instance, it may be that the absence [its] [illegible] vegetation at one level around the point over which the dives occurred evoked the circle-flights, with strong song-display then following from the most suitable perch. The circumstance of a F- with one or two young present in the garden upslope from the spot discussed above again cause me to suspect that the type of display behavior discussed here as part of the