Must be descended from Irish
I know the Irish used to move abroad a lot in the past, like many Poles do now,
but there are gingers all over Europe, and there are even occasional traces of redness of hair in Japan (maybe that's the Ainu).
Udmurts are one of the Finno-Ugric peoples in Russia, somewhere east of the Volga.
They have a relatively high percentage of redheads, and I doubt any Irish settled there ever.