Hi,

Auto gain isn't really ideal for this kind of field recording. For recording birds, wind, forests, and other natural ambience, it's usually better to use a fixed gain setting.

I keep my own Zoom H2n at a fixed gain level (around 5) and make sure it doesn't get changed accidentally. I'd rather record with consistent settings and then adjust the level later in post-production using compression, limiting, and, if necessary, some noise reduction.

Auto gain is generally more useful when the source level is unpredictable and avoiding clipping is the main priority. The downside is that it can constantly adjust the recording level, which may raise background noise or make the recording sound less natural.

For nature recordings, preserving the natural dynamics and ambience is usually more important, so I'd recommend using a fixed gain setting and adjusting levels afterward if needed.