I think it is Taxus baccata is an Old World species of evergreen tree in the family Taxaceae. It is the tree originally known as yew.

It also might be juniper berry seeds.

Hmmmm…. I guess that some rodent must have brought a stem of it from somewhere unknown then. Thank you!

Anyone drop a bag of popcorn nearby?

"it is the tree originally known as yew?"

It is the tree still known as yew.

Not convinced by the ids but have nothing better to offer. Are there fruiting yews in the vicinity? Ime yew seeds are smooth and they have a flattened end.

haha - I thought it might be popcorn too, but it's definitely not. They are lightweight and just a bit smaller than popcorn kernels. I'm not aware of any yews in the vicinity, but that doesn't mean there aren't any!