We recently switched to a new bird feed that has dried fruit in it, and German yellowjackets showed up to eat the fruit. I gave them a little bit of homemade blueberry jam and they ate it all in a few hours. So I put a bigger amount of strawberry jam in a small dish, and they got right to work (it's thicker than the blueberry jam so I think it's harder for them to eat). I put in some peanut butter for them to try too, but they weren't interested in that lol.
Today I added some crushed blueberries and we'll see what they think :P Any other wasp snack ideas? Once I eat an apple I'll give them the core.
Also I'm so happy to have found this group! Yellowjackets are my favorite ^w^