Gymnogyps californianus December 28 1947 Hopper Canyon, Ventura Co. one was a dark headed imm., one a near-adult (dark in center of wing patches), 47 adults. One adult briefly chased another, the hum of their speed sounding like a diving plane. Air calm, sky 7/10 serene & cirro- stratus. 2:14, 10 were in air about 1/4 mile W. of Lookout, 4 11th still perched. Fair SW breeze - no direct sun- shine now. 2:25, 2 adults & 1 imm. perched in Near Roost Tree. The one in next tree downfield (100±yds.) was on tip top, wings halfspread. This one took off with 12 flaps went (slightly down in level) to lowest branch of Near Roost Tree. After 2± minutes it began working up the tree, springing from branch to branch for about 8 "steps" until at level of next to highest limb (lowest on imm. now). To climb up, adult stood with head pointed up toward higher branch & moved head about as if looking over the situation, wings halfspread & somewhat down & back. Then it gave a quick crouch & spring & flap (wings only half out), landed with feet widespread on next branch, & sometimes put bill to branch as if for balance. Then got ready for the next step. Wings were not folded between "steps". At 2:30, only imm. & 1 adult in this tree, then another adult perched between their levels. Some of the scarers had bulging "crops". The imm. in Near Roost Tree seemed about a 3-year old. There were (2:40) 2 adults perched in Saddle Ba., 1 adult &