As ever there is this myth around that squirrels don't like chiili - oh dear, I do so wish it were true!! We have a batch of squirrels in our immediate area, who watch me when I plant bubs and are digging them up before the back door is closed - prickly cuttings from the pyracantha and holly hedges stuck in the ground or around the pots seem to help, nothing else does. They are particularly fond of purple crocus bulbs, and yes, they can tell them from the other ones - they probably smell differently.
I soaked my caged 'squirrel proof' feedrs in chilli paste and oil, and put the powder in the feed, they sniffed at or a day or two, then came back and licked and chewed it all off with signs of great pleasure. The birds come and tell me now when the feeders are full of squirrels!! I have managed with one where the holes seem too small for the adults, but this years young - told by their less bushy tails, so they look even more like rats than the older ones - though of course that is all that they are, can get inside. If the house door is open I can creep out and spray them with water as one does with cats, they're not too keen on that. We have tried the above mentioned chillie, white pepper, garlic, soap amd just about everything else you can think of - and probably a few you haven't. Stll they eat several pounds of seed feed a week. i am reluctant to give up feeding the birds, but feeding the squirrels was never on the agenda.
Pease do not tell me about squirrel proof feeders that slide over the food, they know all about those and how to evade them, they can climb under domes, go up and down the poles until the grease or oil is off then climb up or down and feed - I reallly don't want rats in the garden - if anyone has a new idea that actually works I'd be delighted to hear about it - but so far nothing we have been offered deters them for more than 24 hours.
We have been fighting this battle for 15 years, and so far it is squirrels 15, us 0!!!!