Code 958 Heteroscelus nicana August Okpilak River- On Contact Creek just above the millaw gorge at about 3200 feet, two adult rattlers were seen in the stream bed. They kept flying on upstream ahead of me. One finally turned and flew back past me and I took a shot but missed. On the return trip I again encountered one of these birds. As it kept flying ahead of me down stream. I did not think it would go down past a narrow stepwall serpentine into the millaw area below there and that it would probably turn to turn back upstream at that point - offering another opportunity for a shot. As I approached the rapids I was beginning to think the bird had given me the slip, when suddenly up it popped from behind a rock 30 yds away. It was preparing to take off when I shot it. Just as I was clearing the downstream end of the rapids going into the millaw, the other rattles got up in front of me, flew 20 or 30 yds through the millaw turned abruptly and flew back up river past me.