I try to go for a walk every day for the good of my health. A disused railway line has been converted into a cycle path. Walking through the cuttings is peaceful as the traffic noise from the city flies overhead unheard.

Yesterday I heard a noise that I couldn't recognise. Like a crow's caw, but a lot less shrill. If it hadn't been coming from high up in a tree I might not even have wondered what bird was making it.

Looking closely I saw it was a squirrel, barking. His tail twitched every time he barked. I see lots of squirrels in Edinburgh but they have always moved silently. This is the first time I have heard one call out.