After arriving at the property that morning, the pilot commenced mustering operations. The operations were conducted between 50 feet and 300 feet above ground level throughout the day and all manoeuvres performed appeared normal to ground observers. Later in the afternoon a witness reported that he observed the aircraft perform a steeper than normal climb before diving towards the ground. The aircraft subsequently impacted the ground in a steep nose down, wings level attitude, bounced, then slid forward for 13 metres before the left wing struck a tree. Examination of the wreckage did not reveal any defect with the aircraft that could have contributed to the accident. It is probable that the pilot was fatigued after a long day and that he inadvertently allowed the aircraft to stall at the top of the climb. Insufficient height was then available to allow a recovery to be effected.