Birds like sweet berries.
According to the Wikipedia article, birds can't tell they are bitter: "The fruits are eaten by birds (birds do not taste astringency and feed on them readily), which then disperse the seeds in their droppings."
Well .. you can rely on Wikipedia if you want, but they have a whole section on Statue of Limitations - looks like they left out a letter in the word Statute ..??
So .. I don’t rely on Wikipedia for ANY INFORMATION.