What happened to my blackcurrants ?

I have 3 young blackcurrant bushes planted this year, they've been doing well and amazed me by having a good crop of flowers followed by berries - still small, hard and green yet, but the other night I was checking things and one of the bushes doesn't seem to have any berries left on it, there's one bare stalklet, another bush seems to have fewer as well.  I didn't think anything ate green unripe blackcurrants - I grew blackcurrants in our last garden and nothing bothered with them, not even birds when they were ripe!

I can't see any signs of disease or pests, unless I've missed something ...
anyone know what's happened here?  I was really looking forward to an unexpected mini crop  :cry:

Check out raspberry beetle a real pain in the backs.

Maybe I should net them now, in case it's birds - worth a try!

Yep, I gave that a try a lot of times. It's just fare you try, too.

I used to get some sort of bug (not sawfly) which ate the green berries of all my currants. So far so good at this house. But once the red currants are ready, the robins have a hard time resisting.