egg and leaves

Found this egg in the garden among the Acer leaves.  It's white, which, according to my Big Boys Bumper Book of British Birds Eggs, is probably a Collared Dove or a Wood Pigeon.

Neither of these nest in our garden, although we do get Wood Pigeons raiding the bird feeder and have had the odd visit or two from a Collared Dove.  I'll leave it to the eggxperts to decide.  

According to my dearly departed Ma-in-Law, they were both the same bird anyway, so I don't suppose it matters.