In Ireland there is a lot of interest in the research being carried out by Dr Emma Sheehy and Prof Colin Lawton of Galway University looking at the relationship between pine martens and grey squirrels.
More information can be found here
A a pair of nesting Goshawks being monitored in the Midlands in 2014 by the Forestry Commission and local bird watchers were predating 90% Grey Squirrel. This adds to the Derbyshire nest where 95% Grey Squirrel predation was recorded, and a nest in Devon where Grey Squirrel predation was 68% Grey.
Ecological control can play a part in grey squirrel reduction but multi methods are still needed if we have any chance of significant population reduction.
Pine martin with a young grey squirrel and a Goshawk with a grey squirrel.