Several very small under-road tunnels have been built around the country so they can head towards their mating and spawning grounds safely.
But they face another peril; huge numbers of them get washed down the drains whenever there is heavy rain. There has been plenty of that this March.
At Severn Trent's Netherbridge treatment works near Gloucester, sympathetic sewage workers have set up a rescue patrol for amphibians which have fetched up in the settlement tanks there after a long, underground journey.
The smooth, vertical walls of the tanks stop the creatures from escaping.
They face certain death when they are moved on to the next stage of sewage processing.
So the human volunteers cycle round the large works beside the River Severn, looking for victims.
Then they scoop the amphibians out of the tanks and take them to a wetland conservation area on site.
Eventually they are released in the surrounding countryside. Netheridge's manager, Derrick Sorrell, says that more than 2,000 are thus saved in a year.
t Frog numbers are currently declining in over 140 countries
t Drought is the single biggest influence on frog numbers, as they lay their eggs and develop their young in water.
t Frog secretions may hold the key to curing ailments from stomach ache to schizophrenia. A painkiller 200 times as strong as morphine has been found in frog skin.
t Frog bones form a new ring every year when the frog is hibernating.
t Some frogs can survive well below freezing. The grey tree frog can survive even though its heart stops, by making its own body antifreeze.
t Frogs can jump up to 20 times their own body length in a single leap. The South American sharp-nosed frog has the world record - 10.3m.