Not sure what you heard. The first time I heard foxes mating calls I was freaked out. Sort of sounded like someone screaming in the woods - very eerie. Do a google search for different animal sound files and see what comes closest. That's how I figured out my haunted forest was actually foxes.

I'm beginning to think I heard a different type of tree frog or something like that. It has a vibrating,long even pitch that lasts for about 10 seconds or more. I hear it along with the regular peepers in my woods. I think the clue is vibrating sound. That makes me think it's a frog of some sort.I feel like I live in Africa at night.