Upon arrival in the vicinity of the unpaved airstrip, the pilot made a "mid-field fly over" to check the wind socks, which indicated calm winds. He then flew a low pass along the runway in order to ensure that it was suitable for landing. Satisfied with the wind and runway conditions, he flew a normal traffic pattern for landing. The tailwheel equipped airplane touched down in a 3-point attitude, but rebounded into the air. In accordance with previous experience, the pilot applied forward stick to "stop the bounce," and the airplane continued down the runway on the main gear. According to the pilot, the main wheels "hit a dip" which resulted in a nose down pitching that the pilot was unable to arrest. The airplane nosed over and came to rest inverted. The airplane sustained substantial damage to the wings and fuselage. A postaccident examination of the runway revealed no obvious holes or impediments in the landing strip surface. It was noted that one wind sock on the airport was situated so close to significantly taller trees that it would not have provided valid wind speed or direction information. Review of meteorological information indicated that light winds prevailed for the region. The pilot reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.