Report 39831: Photographer spooked off Big Spirit Lake before he gets his photo

I was photographing the sunrise on Sat 4th February in the morning on the frozen shore of Big Spirit Lake in northern Iowa, it was about 5am, so I had to wait until daylight. I shut off my vehicle, walked out towards the lake and stopped to listen to the ice cracking on the lake. To the North of me I heard three very distinct sounds that I would say we're 'wood knocks', I am reluctant to say that because I don't want to pigeon hole what I heard, I would estimate the distance of the noise to have been within 1/4 mile or so. In response to that I heard from the South at a closer distance the sound of, and I can only describe it as bottles being moved in a trash can. The temp was 4 deg and there were no other vehicles in the area, it is a state campground, but obviously shut for the winter. I saw no ice fishermen in the area until about 6am or later. It was as if the 'whatever it was' to the South was being alerted to my presence by a lookout. I would not consider the area to be highly wooded, but there is an abundance of deer and they obviously hide well in the area. I left pretty spooked cursing the fact I had an slr camera with video capabilities, but being totally alone freaked me out. Have you heard of any Sasquatch reports in the area at all, I can give an exact GPS coordinate or map reference if needed. North west side of Big Spirit Lake, IA, near Okoboji, and Spirit Lake, thanks [name removed by investigator]