Birth rates may be somewhat different, but I don't that's so significant. In the case of former Yugoslavian states, what has happened is that ethnic groups, which formerly used to live in mixed areas, have moved away and concentrated each on their own area.
Serbs have moved to Serbia, Croats to Croatia, Muslims have moved out of these. This was result of a mix of fear, actual violent ethnic cleansing by extremists, but also within each population, just a desire to live within one's own ethnic and religious enclave.
I'd love to know what birth rate gap explains a 85% drop in population in 20 years.
And the ethnic cleansing is happening everywhere in Europe now. Muslim enclaves with only tiny amounts of non-muslims are a fact in every Western European city I know about.
> Muslim enclaves with only tiny amounts of non-muslims are a fact in every Western European city I know about.
That's a ridiculous claim.
Here's a list of largest cities in the European Union by population within city limits. This list ranges from cities with population over 8million (London) to 315,000 (Catania).
Serbs have moved to Serbia, Croats to Croatia, Muslims have moved out of these. This was result of a mix of fear, actual violent ethnic cleansing by extremists, but also within each population, just a desire to live within one's own ethnic and religious enclave.