Yes I know they say they are responsible for the red squirrel numbers I have read a report somewhere that the grey may have the answer to squirrel pox which is the main cause of the red demise, How true it is I don't know
I don't think they've found anything positive yet Derek though there are instances where some reds are developing their own immunity, it's the greys that carry the virus which decimates the reds but it isn't the only reason as the greys are bigger, more aggressive ( typical Americans
= only joking fellas ) and they actively drive the reds out. We had a very healthy population here until a few years ago until the greys arrived and the reds had disappeared in 2 years, trappers got more than 200 greys in one month on the local golf course after which a few reds came back but it's back to square one again now.
there's a huge operation in Northumberland to protect what's left of the local population which are confined to small pockets these days.