That is a Red-bellied snake, Storeria occipitomaculata.
Usually found amoung leaf litter in wooded areas in the southern parts of Ontario. They eat small inverts and get 40 cm/ 16" in length. Red-bellies give live birth in July, between 4-13 offspring.
This species is not considered at risk, but should be returned to a suitable environment soon, these little guys need to den up for the winter