From the regs.
"A person hunting small game may not carry or use a rifle of
greater calibre than a .275-calibre rifle, except a muzzle-loading
gun, in the geograhic areas of Brant, Chatham-Kent, Durham,
Elgin, Essex, Haldimand, Halton, Hamilton, Huron, Lambton,
Middlesex, Niagara, Norfolk, Northumberland, Oxford, Peel,
Perth, Toronto, Waterloo, Wellington or York"
Simcoe / Springwater is not listed.
I could not find anything in the Simcoe or Springwater websites. However, I have heard form several people that you can NOT use anything larger then .275 in my area. I just can't find hard data to back it up.
So.... Yes you can ?