On the occasion of the 100th bLOGOS/HA HA post,
this enlightenment-wish haiku for D and all :
from Wikipedia :
sparrowfart; sparrow fart; sparrow's fart
Has the folk etymology of being the time of day when the birds (including sparrows) first wake up, and presumably fart.
It has sometimes been thought to have originally been an Australian expression, and 'A Dictionary of Slang and Unconventional English' by Eric Partridge and Paul Beale does list sparrow's crow as an Australian euphemism. They list sparrow-fart as both daybreak, in colloquial use since before 1910, and popularised during WWI. Also as used in James Joyce's Ulysses meaning an inconsequential person.