Amazing timing for this story. Was prepping a bacon-wrapped grouse dinner for the next to last night on my recent Minnesota trip. We were down one bird for the number of diners and while out on his boat walleye fishing, I'd arm-twisted my brother into donating one of his birds to the pot (he was, after all, attending the dinner as well). Upon returning to the dock, I immediately marched over to the house and found a very-mature (i.e. big!) male grey-phase laying on the ground next to the deck. The bird was still quite warm and had his crop opened up, spilling out the contents. Not looking a gift horse in the mouth, I immediately carried it over to the cleaning house and prepped it for the later dinner. I had thought a raptor had possibly killed it and dropped it until I went into the house and found the broken double-pane window with the smudges and faint-feather halo. We all attributed it to the ghost of my late father-in-law supplying one last grouse for the camp dinner. Brought my mother-in-law (who'd been fishing with us) to tears.
That red leaved-tree you see out the broken window is what my late father-in-law called a "nanny-berry" bush. The contents of this bird's crop were nanny berries.
