Some calls are very short and may need to be zoomed further to see detail. As you may need to change some of the spectrogram settings it may be easier to copy and paste the interesting clip to a new Audacity window (press Ctrl + n) rather than muck up the spectrogram of the main file you’re scanning.
Here’s a call which on a 30 second view is barely visible and unidentifiable.
Zooming in to half a second shows the call much better but it now appears blurry.
This is because our default “window size” of 1024 doesn’t provide enough resolution. For highly zoomed views of short calls the window size (black down arrow to left of spectrogram, then Spectrogram Settings… needs to be reduced, here to 256, giving a much clear spectrogram, showing two more or less parallel notes, with some modulations towards the end. Its probably a Robin.
For very short calls such as this, Audacity has limited functionality for adjusting spectrogram parameters. The free Raven Lite is a bit better (seems higher resolution, plus allows gradual adjustment of window size) but you may need to consider using Raven Pro. The full version is expensive but the demo version can be used in 10 minute bouts multiple times…). See the Sound Approach blog on robin and flycatcher calls which gives suggestions but this currently feels like a bit of a dark art.
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