1963 Green Is.; Kure Atoll; Hawaii; Pacific Ocean R.Clapp Journal Dec. 17 - Spend morning making a combined census-estimate of haysan Albatross nests on the island. In afternoon spent several hours on activity study where I made a number of observations on red-billed tropic- bird-flight display - Four tropic-birds were involved. All had the long rectrices and unspeckled backs associated with adults. In the display the wing-beat becomes much more rapid, the bird holding its position in the air or moving slightly backward. The bright red tail is depressed while the body is held at a 30-45° angle above the horizontal. From a number of observations it seems that an important part of the display precedes the above - the displaying bird flies downward and then upward in a small arc with the static hovering being initiated at the end of this arc. Another feature of the tropic bird display which may or may not be a regular part of the display is that two birds will glide in a downward arc for from 50-75 yds. both gradually gliding upward into the wing-beating display. The degree of depression of the tail comes a great; from being just slightly depressed; to being depressed to such an extent that the central tail feathers actually point forward (at about a 45°). in the direction in which the displaying bird is flying. Contrary to observations on white-tailed tropic bird; there seems to be no attempt to touch the partner in the display with the rectrices.