Report 1438: Barefoot tracks and whistling heard while hunting

First of all I don't know if this incident is a big deal or not, but I been a outdoorsman for many years and it kind of caught my attention. I was Elk hunting in the Bumping river area of Yakima County. I was walking up the American ridge trail in the am Hours. I had reached a portion of the the trail that was flat and had soft dirt. I noticed a foot print on the trail. My first thought was why would someone walk barefooted up on the mountain. The track was not large. It looked like a slender womans foot print. I followed the track up the trail for about six to eight feet and I then lost sight of the track. I continued walking and I heard a wierd whistling sound. It wasn't real loud, but I definetly didn't recognize it. I started to put things together in my mind (Track/Whistle) and the hair on the back of my neck stood up. I continued up the trail and eventually sat down to watch a draw for any elk that may be crossing. I again heard the whistling sound. I have been hunting in this exact area since about 1977 including other places and I don't recall hearing a similair sound. Looking back now, It seems even more strange that if the foot print was in fact a person that had taken off their shoes to fix their socks or whatever, why would they walk up the trail, especially in late October?