This is some interesting shrew talk, but it is not a shrew. It is a vole which is closely related moles. They occupy roughly the same niche as mice and are fodder for coyotes, foxes and owls.
I'll bet you dollars to donuts it is a shrew. It has the long, pointed snout of a shrew. Voles look more like mice and are bigger, sometimes its hard to tell from a pic, but it is a shrew. As far as filling the same niche, they voles will tear up your garden, while shrews will keep the little bugs at bay.