"Stag farts" - a traditional sign of summer

In the United States, summer unofficially begins well before the solstice - typically after the Memorial Day holiday at the end of May (coinciding with the meteorological "summer"  months of June, July, and August).  That's a good-enough excuse to post about "Sumer Is Icumen In."  Wikipedia provides an extensive review of the piece, including the Middle English text -

Sumer is icumen in,
Lhude sing cuccu!
Groweþ sed and bloweþ med
And springþ þe wde nu,
Sing cuccu!
Awe bleteþ after lomb,
Lhouþ after calue cu.
Bulluc sterteþ, bucke uerteþ,
Murie sing cuccu!...

- and the Modern English equivalent -

Summer has arrived,
Loudly sing, Cuckoo!
The seed grows and the meadow blooms
And the wood springs anew,
Sing, Cuckoo!
The ewe bleats after the lamb
The cow lows after the calf.
The bullock stirs, the stag farts,
Merrily sing, Cuckoo...

- and this clarification:

The translation of "bucke uerteþ" is uncertain. Some translate as "the buck-goat turns", but the current critical consensus is that the line is "the stag farts", a gesture of virility indicating the stag's potential for creating new life, echoing the rebirth of Nature from the barren period of winter.

A hat tip to Adrian for finding an mp3 of the round that you can listen to.