Hi Steven
That's only my guessing. The storks on this vase looks very similar to a float bowl (also unidentified) which often seen to match one of the libochovice centrepieces (like the frog on the bullrushes). I've also seen this vase in dark blue and the shade is very identical to the penguin float bowl which is also made by Libochovice. I have never seen a piece of opalescent glass made by Libochovice, but having said that, it doesn;t mean they don't make them...maybe just a small batch??
Cheers
Brenton