Drought
By Frederick Boyce
This year North Carolina experienced one of the driest springs on record, with
drought conditions occurring in the eastern part of the state during May that
were finally alleviated by the coming of rains in June. Whereas we typically have
a drought in the middle of every summer, this one was earlier than usual and
may have disrupted the normal cycle. While long and severe droughts can have
devastating effects, there are also benefits to the natural drought cycle for many
animals.
The significance of swamps and ditches as vital wetland habitats that basically
function as freshwater estuaries is often overlooked. With their shallow water,
both are very susceptible to the action of drought. Not surprisingly, the effects of
drought can be catastrophic for such aquatic animals as fish and amphibians, but
as it so often seems, the misfortunes of some can be a bonanza for others.
A shy and normally very aquatic spotted turtle takes refuge in a cavity
under the roots of pine tree.
these include nonvenomous banded and red-bellied water snakes as well as
ribbon snakes and the ubiquitous black racers, which have a taste for amphibians
(along with practically everything else). Above aU, however, it is a feast for the
cottonmouths, the most abundant snakes at this location and the primary subjects
of my long-term behavioral study.
K'i .
catfish.—Photos by Fred Boyce
As water levels recede in the shallow swamps and ditches, fish and amphibian
A large male cottonmouth engulfs a dead'Bullhea
larvae (tadpoles) are stranded in shallow puddles, becoming easy prey for a wide
variety of animals. Raccoons and opossums, otters and turtles, a wide array of
birds and even bears partake of the all-you-can-eat buffet, but among the greatest
beneficiaries are snakes, especially semi-aquatic species that feed largely on fish
and amphibians. At my study site in eastern North Carolina (not on Bogue Banks)
Sometimes the tables are tuh^ Ajuvehile cottonrnouth’wascaugHl
traversing an open patch of woods during the drought by a foraging eastern
kingsnake.
IWi.
Hi
A beautiful swamp, empty of water.
Despite their much-exaggerated and mythologized reputations, cottonmouths
are actually rather clumsy and awkward predators that seem to have a difficult
time just capturing tadpoles stranded in a puddle. They are certainly not able
to compete with anglers for healthy fish. Scavengers such as cottonmouths and
snapping turtles actually help clear the waterways of dead and dying fish, keeping
both water and fish healthy. My observations of this population of cottonmouths
over the last three or four years indicate that the^adults are dedicated scavengers
that hardly ever capture live prey. I have often seen adult cottonmouths basking
peacefully on the banks of ditches, taking no interest at all in the abundance of
nearby leopard frogs sharing the bank. Whereas young cottonmouths will use
their bright yellow tail tips as lures to attract small frogs and lizards within range,
the adults seem to have become dependent upon the scavenging opportunities
provided by the annual cycle of drought, much as African predators in the
Serengeti have come to depend on the annual concentrations of prey animals that
crowd dwindling water holes during the dry season.
(Continued on page 9)
4 The Shoreline I July 2021