Mystery Walnut Shells

[Wilthorne]

Hello my first post in an attempt to solve a mystery that has puzzled me for age.

I live near the Gt Ouse flood plain in Cambs and walk my daughter's dogs on them every day when they aren't flooded. All over them I keep seeing perfectly halved and empty walnut shells.
Up to now I have assumed that the nuts drop off trees overhanging the river and get washed out onto the meadows when they flood. The perfect halving is a natural result of getting well soaked in the water and the nuts are then eaten by birds from the opened shells as there is no damage at to the half shells.

But that theory has been shattered this week as I have started finding lots of the empty half shells on top of a recently constructed flood bank some 2 metres above highest water level.
Where would/could the nuts come from?
How are the shells perfectly and cleanly halved?
Who/what eats the nut out of the shell?

Can anybody cast any light on the matter before I go nuts?

Off on a tangent to that, I have started finding empty mussel shells on top of the bank as well. It is over 50m from the main river channel what creature is most likely to take them that far to eat.

[Adam Cheeseman]

Hi there,

Usually when walnuts are involved it turns out to be Rooks or a the very least another member of the crow family involved. Are there any cows around? Rooks will collect walnuts and use cowpats in which to hold the nut steady whilst they prise them open.

Mussel shells I'm guessing at an Otter, assuming they haven't been deposited there by a swollen river.

Cheers,

Adam

[Kayleigh]

There are half walnut shells scattered about in a wooded area where I walk the dog I'm glad you brought this up as I was wondering where they had come from. I will go with the rooks and crows. This field is used to graze cows in the summer. Are the walnut trees close to where the shells are found as the trees have no leaves on them so ID is a bit difficult at the moment.

[Dan Salter]

How funny, We went on 3 field trips with our degree course in the last 2 weeks on Kent wildlife trust reserves and i have spotted and mentioned seeing half walnut shells on all 3 of them, 2 chalk downlands and one wooded

[Wilthorne]

I don't know if any Walnut trees overhang the river - the only one I know of in the area is in the town about 200m (as the crow flies) from the river, the meadow is on the other side of that and stretches at least 1500m end to end. All the shells are perfectly and cleanly halved, almost as if the two halves have been unstuck from each other. I have never seen one damaged in any way and having tried to open Walnuts myself I know just how difficult that is.
The mussel shells are commonest along the river bank, but I saw one the other day well away from the river, on top of a very open, exposed and only recently built flood bank, not a location I would have expected Otters to choose. There are Foxes around and I have seen several piles of bird feathers (wings and tails but not much else) from Gulls, Ducks and Geese around the whole area. Would foxes find and eat mussels?

It is the number and distribution of shells that puzzles me, so many over such a wide area and the cleaness of the separation of the halves.

For anybody that knows it, the area concerned is the flood plain between Hemingford Grey and St. Ives Lock.