I think the red squirrels are more at risk. https://www.northernredsquirrels.org.uk/red-or-grey/ https://www.northernredsquirrels.org.uk/red-or-grey/ says “Red

I think the red squirrels are more at risk. https://www.northernredsquirrels.org.uk/red-or-grey/ https://www.northernredsquirrels.org.uk/red-or-grey/ says “Red squirrels weigh between 270-360g and with a head and body length of 19-23cm. Grey squirrels typically weigh between 400-720g with a head and body length of 25-30cm.” That’s not a big difference (10%) between heavy red and lightweight grey squirrels. Also, that “typically” indicates the difference maybe smaller, or ranges may even overlap.