Tiny Spot??

Last year, at Edgeley Road, I saw a litter of at least three baby voles with white flashes on their foreheads. I was hoping at least one of these had survived to breed, so imagine my delight this evening when, amongst the many voles I saw was this one (top). It didn't look like a fully-grown adult, so is this actually the offspring of one of the Spots? Or is there a genetic code in this colony that randomly assigns white spots? I've seen white spotted voles at White Lion Meadow and at Black Park Road too, which raises all sorts of questions about how far Whitchurch water voles travel, and by what routes. Edgeley Road spotty voles