what is this?

[skylab]

Bought at the flea.
Thanks

[ray]

I would guess that it is for boring a tapered hole using a brace

Ray

[amertrac]

or a feed scoop for canaries

[Lewill2]

Usually called a bung bore, for boring holes in barrels for the tap and/or plugs. One this small might have been used for furniture making, chair rung holes and such. Maybe a look in Sellens book would answer the question.

[Branson]

It does look just like a bung hole auger though the shoulder is a bit mystifying.  Most I've seen are tapered from the end of the square section.  The size makes me think it is a tap auger rather than a bung hole auger -- for setting in one of the wooden taps at the end of the barrels.