What Is This Plant?

Could someone tell me what this plant is that is in my backyard? It’s a tree about 20 ft tall. It is covered with purple berries. The birds don’t seem to eat the berries, so they may be poisonous. The leaves seem to be turning yellow, so the plant may be deciduous (then again it could just be unhealthy).

I am thinking it might be an elderberry. Does anyone know? I am trying to decide whether to replace it or not.


Berries up close

Leaves
The leaves

And a shot of the tree (it’s foggy today):

UPDATE: It is probably a Mexican Elder. The berries taste like leaves and have no juice. The plant is ugly, although it does provide a lot of privacy in the backyard.

Long term plan: Remove tree. Replace with an avocado?

UPDATE 2: Actually, it is a Japanese Privet. I have grown fond of the tree since writing this. It can stay.