Totally OT - can someone help me identify this berry?

Definately not black berries or any type of raspberry, there are no thorns on the vine!

There are thornless blackberry varieties.

Are birds eating them?  If so, yep you are safe.  And definately blackberries.

 I don't know about the birds, but the stupid squirrels are (and they keep dropping them in my pond!!). 

Mulberry. Positive.. 
Edible, but not "bright" tasting like raspberries/blackberries. We have them all over here, considered weeds. Birds like them a lot. 

You can differentiate them both by the way they grow, the leaf shape.. and of course the berry doesn't have the same features as blackberries even.. 

http://www.differencebetween.net/object/comparisons-of-food- items/difference-between-blackberry-and-mulberry/

I didn't think the leaves looked like the Blackberry leaves I have seen, and this is more of a tree then a bu****hanks! I am going to eat one, if you don't hear from me in a few days you will know it wasn't a mullberry LOL

I can guarantee they are mulberries, you're safe! Now, if they are a good tree- great- they'll taste pretty good, a little more seedy than I like personally.. but if they are blah, just leave them for the birds! Watch out for the juice, it stains worse than anything, almost like poke berries (now those are poisonous!- but the young leaves are edible..) Yes, I'm a plant-nerd.. wild-crafting and wild-edibles are a particular hobby of mine! I can name many of our local flora, and explain which are edible, which aren't and how they poison you if they are poisonous vs just icky.. 

 Yeah, very seedy, they would have to go though the food mill before canning b/c it's just a little too much for me.

Oh & hopefully not growing anywhere near your foundation? The roots are horrible and will get into any cracks, broken clay drainage pipes.. They are near impossible to kill.. cut them down to the ground, tons of suckers pop up!

 Hee hee, they aren't even on my property, they are actually hanging into my yard from a neighbors tree, so I am bogarting them LOL