In Croatia, Birk families are predominantly Croats (from Labin area ), rarely Slovenes (from Slovenia ). In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Ivanic-Grad.
Prevalence
About 10 people with faimily name Birk live in Croatia today, in 6 households. There were 20 of them in the middle of the past century, and their number halved. They are located in only threee naselja i to in Rijeka (<5), Lazarici in Labin area (<5), and in Zagreb (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1917 in source List of Dignitaries, Officials and Public Servants of the Kingdom of Croatia-Slavonia.