In The Garden: Can you identify this seed?

I have some kind of animal (probably mice) storing significant quantities of seeds in cabinets, etc. I have attached a picture. Can you identify where these seeds are from?
Thank you.

 

Most of plants from order Rhamnales have seeds with ribs (including families Elaeagnaceae, Rhamnaceae, Vitaceae). Check which of them are abundant around.

 

The look very like grape pips to me.

 

I doubt this is grape. There is no source for grape seeds.