Gymnogyps californicus April 13, 1946 Hopper Canyon, Calif. Ledge (counting points below the main ledge). 6:05: 4 left atop cliff (some adults), 13 on Whitewash Ledge. 6:15, 3 scattered atop cliff (2 or adults). Whitewash Ledge appeared: the 3 rockholes above cave were also occupied & two were on the ledge just above cave top. There was some shift about once per minute a more frequently (6:20). apparently none was crouched w/ head tucked in by 6:25 (59° F, no breeze), 6:30-4 atop cliff, 20 total visible, still frequent shifting. By 6:45 all had left the cliff top. At 7:07 I could count 17 on the cliff & saw 1 fly off. About 7:10 I heard one fly - the last to fly this evening. Stars out but fairly bright moonlight. At 7:30 I could see at least 8 on Whitewash Ledge. During the play around the pool & when birds were on cliff nearby I heard about 6 separate times a grunt which sounded much like suppressed human belch. April 14, 1946 Hopper Canyon, Calif. At 12:40 a.m., by moonlight I observed the cawing on Whitewash Ledge in apparently the same positions they had been in at 7:30 last evening - at least