This odd looking nest is almost 3 feet wide. It was built on top of a witches' broom on a balsam fir tree. A fungus invades the tree and causes it to form a witches' broom which is an excessively twiggy, clump-like formation.
In this case, something (we're suspecting mice) carried bits of deer hair, up 15 feet to where the witches' broom was and covered the entire thing with hair. We don't think that birds ever nested in it because it's completely flat and not cup-shaped.
The deer carcass was found about 50 feet away from the tree. It looked like it might have been there a year or two. We're thinking that the mice lived inside the nest. No one we've asked is quite sure. Odd or what?