This plastic doohickey is designed to dispense yarn for birds to use for their nests.  (Patrick Carney ID'd it correctly; congrats!)

I have never seen a bird go near it.

I am offering it free to a good home (or even a bad home).

As to why I paid $2 for it -- it went to a good cause (the Frelinghuysen Arboretum) and seemed like a good idea at the time.

And now that it has been a Monday Morning Mystery, probably not a total waste.