An account in Alpine County, California

While walking cross-country, looking for possible home sites from the early 19th and late 18 hundreds, I was walking the base of a small ridge between two lakes Lower Blue and Twin Lake. On the ridge side it was mostly open forest on the Twin Lake side the brush got thicker. As I was walking I heard a loud two tone whistle [low to high pitch] that was not a bird or any animal I know. The sound came from ground level and behind me to my left. The whistle was loud and sounded in my opinion from a mammal. I turned and called out thinking a hunter [in a place he should not have been][no hunting zone] but no one answered, I whistled back but nothing called. Wondering what it was, I investigated the area 'till i could get no farther, the brush was too thick. I was standing within 10 feet from where the whistle came from, nothing in sight not in the trees on the ground not anywhere, no bird's where flying and no animals in sight either. It was a little spooky but at the time i was cross-country running almost 5 miles a day at 8000 feet as well as boxing training and being a good bow hunter nothing scared me at that time. I was 20 with a good outdoor understanding and other people were the only things that scared me. I remember after I got back to the cabin and asked my Dad what animal out there [if he knew] that whistled like us but much louder, he didn’t know of any. I did not think anything about bigfoot even though I was interested in the subject, I thought they were all up north in the Shasta and up area. I did not know that BF made whistling sounds until I went through the BFRO website.