Are Mahonia Berries Edible By Human?

Q: In late April I saw ten birds attack my mahonia shrub. I watched bird after bird swallow those beautiful blue berries down their throats like a snake does his dinner. Are mahonia berries edible by humans? 

A: I’m not a doctor but several websites mention that mahonia berries are edible when fully ripe and soft. One source says the berries contain berberine, which might be harmful in some situations.