Save the Squirrel (but just the red ones...?)

I saw this report on the BBC News website today, and it reminded me of a joke about the shortage of red squirrels. How do we know that the grey squirrels aren't old red squirrels. We've got lots of squirrels parading around our garden - and they are surprisingly noisy. Ultimately, aren't they just cute rodents with furry tails?

http://www.bbc.co.uk/news/science-environment-15066066