It is quite normal behaviour, and not just for woodpeckers. The birds
have moved out into nearby woodland to take advantage of the usual
summer abundance of natural foods, and haven't needed to visit your
feeders. Great Spots are largely insectivorous in summer but take
increasing amounts of tree seeds especially from pine cones as they
become available in the summer and autumn. They sometimes feed on the
cones while they are green.

Thanks for that Malcolm.