Around my work I walk in local parks for a couple of hours a day, and I've noticed we have Green Woodpeckers, and I've seen them quite a few times and can now recognise them rather easily.
Recently I have seen Spotted Woodpeckers, I assumed it was a Great Spotted Woodpecker, however recently learnt we have Lesser Spotted Woodpeckers in the UK as well. It was pouring with rain at the time so I was unable to get a very close look at the pair. How would you tell the difference between Great and Lesser Spotted Woodpeckers by their look and behavior?