Report 49971: Possible whoops heard while stargazing near Van Buren

On 10-11-2015 at approximately 10 pm I was driving around and thought I would stargaze at the old conservation fire tower on 21 highway near the old 21 drive-in. I parked my truck by the picnic table. I turned off my truck and got out looking at the stars. It was just a moment and I noticed a whooping call it sounded like a monkey at the zoo. I listened for a good 20 minutes the call was the same a whoop whoop then a pause for a short time then another whoop whoop. It sounded like it was coming from the heavily wooded valley below me.