Wow, I have come across something like that before in the forests South of my house, stairs out in the forest...In a forested area, no idea how it got there, a set of stairs...I've walked about in the forests all around my area and in certain parts of the mountains and found strange things randomly...
Once my dog and I were crossing a meadow and the grass was about a meter tall, following an animal trail we found an open patch with a deer skeleton, picked clean...I looked up and hidden in the tall thickets 50 feet away was a barn...
Looked around and saw no other structures, I wouldn't have noticed it if I had not stopped to check out the deer bones...My dog a few meters ahead of me we go to tigate, the barn door is closed and I see a upper window is open...
I open the main door, this barn is about 50 feet square, may be a little bigger, I see random ancient stuff, old craftsmanship, tables, a chair, pictures, an old bike...Then we hear this low hissing sound, then multiple hissing sounds...
It made my skin crawl, it was an eery sound, my dog was a little shaken too and went back to the door...Then I hear movement in the lofted part, it's dark up there I can only hear many things coming out to the edge of the loft right above me...
I was freaking scared, my dog alraeppeady bailed out, he was outside barking, these things were moving into the light from outside, I was backing away but I couldn't move any faster, I was frightened and looking I see what they are, buzzards, four big buzzards and babies...
Those big birds were hissing at me protecting their babies lol...I wasn't scared anymore, inside laughing at myself for getting myself all worked up I left and continued our hike...lol