Mating squirrels make the MOST bizarre noises!
Like someone clicking their tongue only sorta dully and making a brrrm brmm noise without the b and also a noise like a wheel spinning combined with the noise of a cat starting to chuck.
Or at least that I what I assume is going on, given that there is a black squirrel with its tail up and a normal coloured squirrel chasing it but not in the usual fashion of "get outta my territory!" where they don't get near each other... No I would say the black squirrel is saying "Catch me if you can!"
Much catching up to do. So many pictures, so little time!