Hello Olga, wow, what a beautiful post.
You made me aware of the city of Lviv (Leopoli in Italian), which I didnt even know, and I discovered what an important city it was in recent history and that Spielberg filmed some pieces of Shindler's List movie there.
I'd like to let you know that probably that blue egg was a thrush one.
Stryj Park have to be really a beautiful place as I can feel from your pictures, it remembers me Parco Sempione here in Milan.
One last thing: despite how lovely swans may appear be cautious whit them, particularly if they are brooding or has little pullets with 'em as they can get really aggressive and territorial and they can attack even humans if feel threatened.

Have a great day.
Giuliano