Roland, a MammalWeb trapper, sent in this photo which seems to capture the native/non-native squirrel conflict rather well! The photo was taken in southwest Scotland, as part of a squirrel monitoring project with which Roland is involved. Roland notes that the photo was taken in a wood in which red squirrels are abundant but grey squirrels are actively controlled. Contact between the species is highly undesirable because of the risk of transmission of squirrel parapox viris, which the grey squirrels carry but are apparently unaffected by. Red squirrels, by contrast, are highly vulnerable to the disease. There was an outbreak recently near Dumfries, not far from where this image was captured.
The photo was taken using a Xikezan R20 camera trap, which is one of the cheaper camera traps that Roland has tried out.