Surname root of feminine surname from Poland - 'onka' ending

My great grandmother had my grandfather, who was illegitimate, in 1870's Vienna. Her name in the hospital records was Scheblonka, she was single, from Krakow, born 1850 and both her parents are died in 1850. There are no records of her in Vienna either before or after the birth.

What male surnames should I be looking for? Onka seems to be the surname ending for unmarried females.

Why would anyone travel from Krakow to Vienna for a illegitimate pregnancy?

Thanks

Scheblonek I assume

I will try Scheblonek / Szeblonek on geneteka.genealodzy.pl surname search.

I did have a Google though and it seems that it would still stay as Scheblonka though. Scheblonka itself doesn't sound Polish, perhaps Czech?

The hospital and findelhaus records in Vienna have Anna Scheblonka coming from Krakow. I doubt she was Czech.