The old adage that April showers
bring May flowers remains true, even as the planet warms and the timing of many
events in the natural world shifts one way or the other. But what is equally
true is that March showers bring frogs and salamanders. So we should pay close
attention as we drive dark roadways during evening rains this month, because
those amphibians will be on their way to and from their breeding ponds, which
often means crossing roads. It would be a shame if our vehicles bring their
annual migrations to a violent end just before the creatures complete their
mission.
Several species of frogs and
salamanders that are crossing roads this month have the remarkable ability to
hibernate among the leaf litter and in shallow burrows during the winter, at
which time most of the water in their body turns to ice. And yet as
temperatures warm, they unfreeze and go about their regular activities. They can
do this thanks to their ability to produce a concentrated sugar solution that
acts like anti-freeze to prevent damage to sensitive organs. This anti-freeze
is triggered when their body temperature falls and their metabolism drops. Sometimes
their hearts even stop beating.
Wood frogs and spring peepers – both
small, tan colored animals – are perfect examples. They are best known as the
loud-mouthed frogs that congregate in vernal pools and small ponds in March and
April as they seek mates and lay eggs. They are often joined by spotted
salamanders, which are attractively dressed in shiny black with bright yellow
spots. But getting to their breeding ponds is often a dangerous trek, and many
don’t make it.
Compared to birds, many of which may
travel thousands of miles to the Tropics and back each year, the migration of
local frogs and salamanders is nothing to brag about. A 2005 study by
researchers at the University of Rhode Island found that most spotted
salamanders only travel about 150 meters from their wintering site to their
breeding pond. Yet because of the fragmentation of their habitat by roads and
houses, it’s often a trip fraught with danger.
Their migration typically occurs
during nighttime rain storms as the weather warms in mid- to late March, though
it got an early start this year due to our unseasonably warm February. (Cold
winters like last year – when many breeding ponds were still frozen until April
– can delay the trip for several weeks.) If you drive dark roads near wetlands
at this time, your headlights will likely illuminate frogs hopping across the
road. Please be careful.
Last April during a warm evening
rain shower, I walked a one-mile stretch of road adjacent to a series of ponds
near my house, and with flashlight in hand, I found more than 50 wood frogs and
spring peepers attempting to cross the road. I escorted each one to safety in
the direction they were facing. It’s a good deed that youth groups and other
interested parties engage in frequently during this season. And you can, too.
If you want to get even more
involved in studying and protecting our local frogs, become a Frog Watch
volunteer and monitor amphibian calls at nearby ponds. The national citizen science
project is managed locally by Roger Williams Park Zoo.
Most important, however, please drive
slowly and carefully during evening showers for the next few weeks to avoid
migrating amphibians. Thousands of frogs and salamanders will thank you for it.
This article first appeared in The Independent on March 17, 2016.
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