Salt Source? Poem by Ima Ryma

This butterfly's most fav'rite food
Is flower nectar, and so I
Am very often in the mood
To land on flowers as I fly.
But my instinct does tell me that
I need to ingest salt also,
Not found in flower habitat.
So other places I must go.
Most often mud puddles be where
I find the salt that I do need.
But I spy a spot from the air
That does look less messy indeed.

Could be some salt there I suppose.
So I land on a Fox's nose.