The baby squirrel was taken to the National Wildlife Rescue Center in Fishcross to be rehabilitated by by Sheelagh McAllister.
"Sheelagh is our most experienced red squirrel rearer and Billy currently needs fed by syringe every few hours," the SPCA said.
Billy will be fed by syringes for about five weeks and will remain at the shelter until he is completely independent.
"Ideally, he'll be part of a group of red squirrels that can be returned to the wild together, at a supported release site," the SPCA said.
The SPCA warned anyone performing lawn work to keep an eye out for squirrel habitats during nesting season.
"Nesting season for both squirrels and birds is well under way so we urge people to take care when cutting down trees/trimming hedges," the animal charity said. "It's best to check for nests first to avoid any accidents."
