Spring means breeding season for toads and, in Philadelphia, that means closing off a city street so the tiny creatures are safe from traffic as they seek their mates.
Each year, volunteers organise the Toad Detour in the city's Roxborough neighbourhood, where American toads leave the woodlands of the 350-acre Schuylkill Centre to breed across the road at an old reservoir.
The toads tend to enjoy wet weather and warm temperatures, so when evenings fall, organizer Lisa Levinson sends out an email to some 150 volunteers to help the toads cross the road.
The breeding season stretches about a month, during which time traffic is diverted from the area and the street is closed off with barricades, courtesy of a permit from city officials.
Levinson launched the effort, now in its third year, after realizing that what she thought were leaves were hopping toads on the street.