I don't know about other parts of the world, but here we have squirrel nests. Google 'squirrel nest image' and you'll see.

I have never done a study, but people tell me that squirrels winter over in them. We can get temperatures as low as 25 below zero, and I believe the squirrels would have to take shelter somewhere in order to survive that. So I guess I accept the idea that they winter in their nests.

I have a 'squirrel-proof' feeder which operates on a counterweight. It worked fine for many years, until a clever squirrel figured out how to hang off the overhang, as described above. I bought a tube of lithium grease at the hardware store and coated the edges of the roof with it. End of problem.

I let the squirrels have all the seed they want off the ground. [Beats letting rats get it.] But I want the birds to have the first chance.