looking at Stubby again, i don't think it's pregnancy.
i forgot that pregnant females usually show signs of having been had, a "landing strip" of missing back fur that takes awhile to grow back.
plus, as pregnancy progresses , they start removing their "jackets" to use the fur to line their nests.
the past couple years i haven't seen very many pregnant squirrels, as i did initially. i think the neighbourhood has reached capacity.