Great spotted woodpeckers are notoriously aggressive on feeders and generally won’t tolerate other birds trying to feed at the same time, but this Suet Fat Ball Feeder Ring provides enough width for the species to feed on one side with a Blue tit on the other – and with no apparent confrontation. It seems likely that the distance between the two birds is sufficient for the woodpecker to tolerate the Blue tit, and for the Blue tit not to see the woodpecker as a threat. Here's a link to the product https://www.vinehousefarm.co.uk/fat-b...