just a heads up, NOT sure what the law's are up your way, but down here in PA<
a good buddy of mine got a TON of fines for shooting the dam rats out of season a neighbor told on him
so careful there
I have had great luck with live box traps
I set a pile of sun flower seeds on the floor, and they go right in
I would wait till I got a few and then as others have done, take em for a ride as far away as I feel like it
I always try to go over 5+ miles, as the dam things DO come back??
there super territorial, as to the gray one
and will get chased far too , in the new area when others find them there!
spray can foam can be a great tool to seal holes
BUT if they been using one a LONG time they are smart enough to chew thru it to re open
best plan as said above is SEAL the place up tight
at my hunting cam we had issue's with mice
he took a few water jugs, filled them with a few gallons of cooking oil, and then left them at an angle with a way for things to get INTO them, sprinkle some Oats on top, (floats)
and then when the suckers climb in to get to the oats they get stuck in the oil and cannot climb out, they then drown, and well, being in the oil, they don;'t get all funky smelling
as we some times don't check things for months at a time
kind of pickles them LOL
I would think this would work with red squirrels too, as they should be small enough to get into a 5 gallon water jug
maybe some peanuts in the oil as a lure!! OR even just peanut oil on top of some what ever Cheap oil you can find