[Closed] mimicking birds on the trails

I'm away from home nightshift, so have just had a wee blast on the red rock trails north of inverness, I was the only car parked up so new the trails were empty
I got the fright of my life approaching the top of first climb as I heard the distinct sound of a hope freewheel off to my side, it was going like the clappers, I thought I was going mad as it dissapeared as quick as it came.
then again 2 or 300mtrs on again I heard it, this time after the hope sound came a chainsaw, its then I realized it was a bird, he was probably listening for new sounds but my hubs a good one,,,, its qiuet

So what kind of bird does this then, it proper gave me the willies as I was searching the trees for this speeding hope hubbed bike