Heard in the woods near Bristol

I heard this strange call in a wood near Bristol in England on 24 May at about 11am. There are deer and badgers and foxes in the wood (which covers a large area), but I have no idea what animal is making this sound (the same sort of call was repeated 5 or six times. This is a recording of the last time we heard it. Does anyone recognise what it is? The video shows nothing of interest - it was merely a way of recording the sound.