Nearly 5,000 Eversource customers in Fairfield County lost power Thursday morning after a squirrel got into a substation and shorted out equipment, according to the utility. It happened just before 8 a.m., with the largest outages in Weston, Westport and Wilton. Eversource said service was mostly restored within about an hour. The squirrel did not survive. The utility says animals were behind nearly 3,000 outages statewide last year.