Some kind of nest?
Now that the leaves are down, we are seeing a large, vertically elongated "ball" of what appears to be mostly leaves, way up in an evergreen tree. Is this a squirrel nest, or something else? We're estimating it's at least a foot tall. We haven't seen anything come and go from it, but we do also have hawks, owls, etc., in the area.
Hennepin County Minnesota
It could be either a hawk or a squirrel nest. Hawk nests will typically be at the very top portion of a pine or spruce tree. Below is a link about red squirrels that briefly describes their nests. https://www.dnr.state.mn.us/mammals/redsquirrel.html