(Or, for that matter, in pet photography or flower photography.)
Darwin Core (DwC) is a metadata standard designed for storing such information a species, behaviour and other relevant biodiversity tags. Frank Bungartz at the Charles Darwin Foundation has implemented DwC as an XMP schema and it has been included in exiftool for a while now. It will also appear in the next version of exiv2.
So, a couple of questions:
How do nature photographers currently manage this type of data?
What would it take to include this data in your workflow?