When I arrive at the Sequoyah National Wildlife Refuge in Oklahoma before daylight, I have to avoid running over the frogs on the roads. You will see lots of them now, hopping across the roads and even some on the trails after the sun rises. Trying not to run over one is very difficult.
I did some research to try and find out why so many frogs like being on the roads. Scientists aren’t sure their motivation for roadway attraction. At certain times of the year, such as the start and end of the breeding season, they move. This type of movement is known as migration. Young frogs may also leave the area they were born and move to a new one. This type of movement is called dispersal.
Most of the research information I discovered was in reference to spring time movement. This kind of behavior is common in spring and early summer when frogs and toads go looking for mates and suitable breeding sites.
I think the best answer I found was that rain makes everything wet enough the frogs can get around comfortably, without fear of drying out. We have had some good rains here in August and September. With the rain and other factors, we have had a bumper crop of frogs this year. The juvenile frogs need to find new habitat to grow.
The photo below is a Leopard Frog I came across on one of the asphalt trails at the Refuge. I read that the Leopard Frog is known to be very mobile.
Leopard Frog - Sequoyah National Wildlife Refuge - Oklahoma