January 2024 - 17

by placing eight audio recorders in areas with
known or suspected breeding populations of
amphibians. The recorders were placed in
early April and removed in mid-July. They
are battery-operated and turn on to record
10 minutes of every hour between 10 p.m.
and 4 a.m.
" They only record 60 minutes a night, "
Nikirk said. " But if conditions are good, the
frogs or toads call so prolifically that even
in that short time window the recorder will
pick them up. "
The recorders are checked periodically for
maintenance. When they are dismantled, the
recordings are downloaded and run through
specialized software that identifies calls from
every species recorded.
" All eight acoustic recorders picked up
Great Plains toads in 2023 compared to only
five recorders in 2022, " Nikirk said. " So little
is known about their distribution. We are
still learning about the areas they inhabit.
If documented in one location one year, we
purposefully move to a new location the
next year. "
The recorders also documented Plains
spadefoots, Rocky Mountain toads, and
boreal chorus frogs.
In July and August, surveys moved up
in elevation as Sheridan Region personnel
joined efforts with herpetological technicians
to survey 15 sites in the Bighorn Mountains.
According to Nikirk, the Bighorns support
glacial relict populations of Columbia spotted
frogs and wood frogs that are isolated
from populations found elsewhere. Northern
leopard frogs also occur there and represent
some of the few high-elevation populations
remaining for this species in Wyoming.
The surveys are conducted by two individual
observers or two teams of two observers
who walk the perimeter of designated water
bodies for a timed period. The observers
record the species, number and age - juvenile
or adult - of every frog seen.
" We were excited to see several Columbia
spotted frogs near Sibley Reservoir this year, "
Nikirk said. " The last handful of years we
found very few. "
Surveyors also captured, carefully swabbed
and released five individuals from each species
at each water body to test for chytrid
fungus. Chytrid fungus, Batrachochytrium
dendrobatidis or Bd, has caused amphibian
declines worldwide and was first detected in
the Bighorns in 2010. Any population-level
The Bighorn Mountains support a population of northern leopard frogs, which represent some of the few highelevation
populations remaining for this species in Wyoming. (Photo by Patrick Owen/WGFD)
A tadpole from a wetland was surveyed below Twin Lakes Reservoir in the Sheridan Region in July 2023.
(Photo by Christina Schmidt/WGFD)
effect it might have on frogs in the Bighorns
is yet unknown.
" If a population is susceptible to chytrid
fungus, it could decline or go extinct,
depending on how susceptible that population
is to the fungus, " said Estes-Zumpf.
" Fortunately, we are finding that several of
our native amphibians in Wyoming seem to
be relatively tolerant or resistant to chytrid
fungus. But other species, like the boreal
toad and Wyoming toad, have been severely
impacted by the pathogen. Susceptibility
also can vary between populations of the
same species. "
Estes-Zumpf noted that survey data is still
being analyzed, but capturing calls of the
Great Plains toads across multiple locations
is a positive finding.
" In places where we are concerned about
populations, these annual surveys at established
sites allow us to track population
trends and respond more quickly if there is
a problem, " she said.
- Christina Schmidt is the information and education
specialist in the Sheridan Region and a regular
contributor to Wyoming Wildlife.
Wyoming Wildlife | 17

January 2024

Table of Contents for the Digital Edition of January 2024