This probably isn't the right area for this post, but I can't make one in the more relevant area.
Anyhow, I live in northern Illinois and we keep hearing this sound, usually but not exclusively at night... seems to be coming from either the steps in the backyard or the backyard porch.
https://youtu.be/2POVP2Dayd4
The noise in question. Sorry it's not great but not sure I want to go outside til I know what it might be.
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