Yeah this happens to me more than I'd like to admit. Captured something last autumn out on the moors, sounded like a low hum when I first played it back on my recorder. Got home, ran it through Audacity, and it was clearly a two-syllable word. Possibly a name.
The weird thing is I've had it go the other way too - something that sounded dramatic in the field turned out to be wind interference once I cleaned it up.
My theory is the environment messes with how we perceive it in the moment. You're stood in a cold dark location, your brain is already primed to find something, so you hear what fits. The software strips all that context away and you get the raw thing.
Anyone else using Audacity or similar to analyse theirs? Curious whether the difference in perception is consistent across different recording kit as well, because I've wondered if cheaper recorders introduce artefacts that our ears interpret differently depending on the playback device.