Yes it looks like it's a Berberis. Thanks !

I just ate a berry (what the hell) and it was sweet with a bitter aftertaste.
It figures. The old lady who used to live here planted a pear tree next to it and she probably made jam from it

I will harvest and freeze some for making jam later. Wonder if I'll need pectin? Who cares. I think it will turn out alright

No trouble with birds, most of them are ripe and still there.
I'll just take a pound and leave the rest for them, if they promise to get serious with the slug population, then we have ourselves a deal

In return for helping me here's a tip if you have a plum tree and it drops unripe fruit in the wind. Collect them and make green plum sauce (search for Georgian recipe online 'Tkemali'). It makes a seriously powerful spicy bitter condiment that will blow you away and rip your tastebuds. I know. I tested in on a friend and he started shivering and covered in goosebumps from one spoonful. Don't waste any green plums you've got a serious sauce on your hands

Martin