Keep a log. That way you have some chance, albeit a small one, of correlating what you hear from day to day, week to week, month to month to something, anything. Moving this, changing that, replacing that, time of day, whatever. Unfortunately, and I say this with the utmost sincerity, you won’t be able to correlate the sound to things you don’t know about or things that are not usually thought to have any influence whatsoever on the sound, that you would never suspect.
Made the scene
Week to week
Day to day
Hour to hour
The gate is straight
Deep and wide
Break on through to the other side
Break on through to the other side
Made the scene
Week to week
Day to day
Hour to hour
The gate is straight
Deep and wide
Break on through to the other side
Break on through to the other side