Managing for massasaugas - The eastern massasauga - Edward Lowe Foundation
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Land
® Stewardship
Managing for massasaugas
T he eastern massasauga
rattlesnake, a federally
threatened species, plays an
important role in biodiversity.
“Massasaugas serve as both predator
and prey, which makes them a critical
component in the environment,” says
Mike McCuistion, vice president of
physical resources at the Edward Lowe
Foundation.
Because the massasauga’s
primary diet consists of mice, voles
and other small mammals, they
help control rodent populations
— which, in turn, helps reduce the
tick population. The snakes also
provide food for hawks, owls and
other predators. “For biodiversity
to thrive, you want as many native
(Top) An eastern massasauga rattlesnake found at Big Rock Valley.
species as practical,” McCuistion (Inset) Mike McCuistion, vice president of physical resources, helps
explains. “If one plant or animal researchers find snakes to collect data for a longitudinal study.
begins to decline, it can disrupt the
balance of an entire ecosystem.” some of the snakes often migrate Fields vary between tall, dense grasses
to drier upland areas that can range and open areas with more light. This
Encouraging biodiversity from forest openings to old fields gives the massasaugas greater access to
Although the Edward Lowe and prairies. Disturbances in these rodents — and makes it easier for them
Foundation’s primary focus is grasslands while snakes are foraging to regulate body temperature — while
entrepreneurship, it is also committed (e.g., mowing, haymaking or cultivation) simultaneously protecting the snakes
to land stewardship. Big Rock Valley can cause high mortality. To prevent from birds or other predators.
(BRV), the foundation’s 2,000-acre that from happening, the foundation’s
property in southwest Michigan, environmental team limits management Slowing down succession
features a broad variety of landscapes in areas near known massasauga To prevent trees and brush from
and ecosystems, with massasaugas habitats to dates when the snakes are in taking over wetland areas and converting
adding to species diversity. hibernation. the habitat to woodlands, the foundation
To encourage its massasauga The foundation also has converted thins wetlands by hand and through
population, the foundation’s many established cool-season prescribed burning. “Yet we conduct
environmental team engages in grasslands to prairies. In contrast to the burns in colder months when the
a number of practices, such as cool-season grasslands, prairies offer snakes are hibernating,” McCuistion
establishing grasslands near known greater diversity of height, texture and says. “In addition, we use back-burning
habitats. structure. Prairies generally support techniques when practical to create slow
From fall through spring, a much greater number of individual moving flames so wildlife can escape.”
massasaugas typically live in wetland plant species (often 50 to 100) per acre Education is also important
areas. In summer months, however, than cool-season grasslands. The result: to correcting misperceptions of
LAND STEWARDSHIP | Edward Lowe Foundation
thinning out trees and brush around the context and a better understanding of
hibernaculum so the ground could what normal survival rates look like, she
Best practices heat up more quickly. adds.
In 2009 the foundation Eric Hileman, the EMRSSP’s
at BRV forged a partnership
with the Eastern
quantitative ecologist and an assistant
research professor at Mississippi State
Massasauga Rattlesnake University, has conducted several
The foundation encourages its massasauga Species Survival massasauga studies of his own at BRV,
population in a variety of ways: Plan® (EMRSSP), and the resulting data has been used to
a consortium of enhance the EMRSSP’s annual findings.
about 17 zoos. Since In one project, which leveraged data
• Establishing grasslands near habitats from BRV and 46 other sites, Hileman
then, the group has
the snakes are known to frequent. been conducting demonstrated how life history traits
• Introducing more native prairie plants. an ongoing field vary across the snakes’ range, such as
• Managing key habitats to slow down study at BRV to offspring being heavier in regions with
natural succession. collect genetic and higher annual precipitation.
demographic data — In another project, Hileman
• Educating staff and neighbors about data that is being used for developed a more precise tool for
the importance of conserving population modeling and to determining when snakes emerge from
eastern massasaugas. inform conservation plans. hibernation. In the past, April 15 was
“The partnership is important used as an arbitrary calendar date for
because few long-term datasets exist emergence. Yet by leveraging soil probes
for this threatened species,” points out and game cameras near hibernaculas at
massasaugas, Lisa Faust, senior director of population BRV, Hileman demonstrated that when
and the foundation has hosted ecology at the Lincoln Park Zoo in soil temperatures at 30 centimeters and
workshops on the massasaugas Chicago, who serves as EMRSSP’s field 60 centimeters invert and the shallower
in conjunction with the Michigan conservation adviser. “To understand soil becomes the warmer temperature
Department of Natural Resources for how a population is changing, you need for a few days, snakes begin to emerge.
its staff and the community. Although a solid baseline of what that population This is important knowledge for land
the eastern massasauga is venomous, used to be like.” managers so they can better time
it’s a docile, nonaggressive species that Armed now with 12 years of data, prescribed burns.
rarely threatens humans. In Michigan the researchers estimate that BRV has
few massasauga bites occur with no about 150 adult massasaugas — and Ongoing monitoring
known fatalities in 40 years, according the population seems to be healthy and Not many properties have habitat
to the U.S. Fish & Wildlife Service. have good reproductive rates. This is management and research activities
especially good news in light of a recent going on at the same time, says Yu
Researchers at BRV fungal disease. “There is some evidence Man Lee, a conservation scientist
The foundation also promotes its of the disease being present at BRV, but with the Michigan Natural Features
massasauga population by hosting we don’t see it impacting the population Inventory, which has partnered with
researchers on its property. in a meaningful way like in other sites,” the foundation on educational events
For example, while a graduate Faust says. and research.
student at Central Michigan University, In addition to its longevity, the Active monitoring is especially
Matt Cross conducted a two-year study BRV field study is also important important when it comes to animal
on how eastern massasaugas react to because it takes place in the middle of species, Lee points out, noting it’s
prescribed burns. Cross also found a the snake’s geographic range, Faust important to make sure management
hibernaculum in a woodland area with adds. “Most massasauga studies have practices are effective and determine
a full tree canopy — unusual because focused on areas in the extreme south which techniques are better.
massasaugas like the sun. or north. Because climate change is “When managing vegetation, you
After consulting with several changing environmental conditions, can tell what’s happening,” she says,
massasauga experts, the foundation’s having a study in the dead center of “but it’s difficult to know what’s
environmental team began the massasauga’s range is very helpful.” happening to an animal species
modifications to encourage the And in contrast to studies that look at without actively monitoring them —
snakes in this area, such as creating declining snake populations, data from especially massasaugas, which are hard
a corridor to a nearby wetland and BRV’s healthy massasaugas provides to see.”
LAND STEWARDSHIP | Edward Lowe Foundation
In search of snakes
Zoos conduct multiyear study
on massasaugas at BRV
I n 2009 the Edward Lowe
Foundation partnered with the
Eastern Massasauga Rattlesnake
Species Survival Plan® (EMRSSP) to
conduct research at Big Rock Valley
in other circumstances.
“We discuss how many births we
need to support the population, which
snakes we want to breed, and with
whom,” says Lisa Faust, senior director
(BRV), the foundation’s home in of population ecology at the Lincoln
southwest Michigan. Park Zoo who serves as the EMRSSP’s
Like other SSPs sanctioned by the field adviser and coordinates the group’s
Association of Zoos & Aquariums, work at BRV. “Then based on those
the EMRSSP is a collaborative science- recommendations, we move the animals
based management program that strives around to different zoos.”
to enhance the captive population of A good portion of the group’s time
a particular species and promote its at BRV is spent outdoors, combing
conservation in the wild. With members wetlands, woods and marshes in search Billie Harrison, a technician at the Milwaukee Public
from about 17 North American zoos, of snakes — part of a longitudinal Museum, has been working on the massasauga
the EMRSSP focuses on the eastern study that will determine, among other study at BRV since the EMRSSP’s inception in
2009. “The property is a gem,” she says. “It has
massasauga rattlesnake, a species that things, survival and reproduction a spectacular variety of wildlife and has been so
became federally listed as threatened in rates. “The goal is to find as many well managed, I really look forward to coming back
fall 2016. massasaugas as possible and then follow every year.”
Since 2009 EMRSSP members them through time,” Faust says.
have been traveling to BRV each May Easy to say, hard to do, for the of ecosystems and habitats, including
to hold their annual planning meeting eastern massasauga is a shy snake that wetlands, which are the massasaugas’
where they review breeding practices likes its privacy. In fact, during the preferred habitat. In addition, the
for massasaugas within member zoos, group’s first visit, EMRSSP researchers foundation has an active management
which are managed collectively. These and foundation staff members found program to enhance its rattlesnake
snakes are not usually captured in the only 16 snakes — which took 275 man- population. “That was also important
wild. They are typically bred in captivity, hours to accomplish. because we wanted to go somewhere
come from nature centers or have been The foundation was selected for that had a healthy, stable population of
rescued by law enforcement agencies the EMRSSP study due to its known snakes to study,” says Faust.
that discovered the animals being population of massasaugas. Comprised When researchers find a massasauga,
illegally traded in the pet trade or held of 2,000 acres, BRV has a wide variety they first collect environmental data
Looking for massasaugas is tough work. Researchers spend hours combing through wetlands — a favorite habitat for the eastern massasauga —
as well as woodlands and grasslands looking for the shy snakes.
LAND STEWARDSHIP | Edward Lowe Foundation
or so later, a recapture could provide
about conditions in which snakes are Recaptures are essential to the valuable information.”
found, such as humidity and temperature research — not only to study survival Twelve years into the project, the
levels, both at ground level and six inches rates but also so researchers can more researchers have found and collected
below. They also take GPS waypoints so accurately determine how large the data from more than 950 unique
they can return the snake to the same snake population is. individual massasaugas at BRV. “That
location it was found. Yet not all recaptures are taken back sort of dataset is rare for any species
Then using large tongs, the to the lab. If the discovered snake is an other than long-lived mammals,”
researchers carefully lift the snakes Faust says. The data
and place them in special cloth
bags inside large plastic containers, “The goal is to find as many is being used to build
computer models that
which are taken to the foundation’s
EcoLab. There, researchers
massasaugas as possible and then could determine which
life stages are more
measure and weigh the snakes. Sex
is determined and blood samples
follow them through time.” vulnerable — and other
information that could
are taken for future genetic, — Lisa Faust help state and federal
nutritional and disease analysis. agencies enhance
Because massasaugas have unique adult that had been captured just conservation management practices for
coloration patterns (known as saddles), a couple weeks before, researchers massasaugas.
they are photographed to help identify typically leave it undisturbed. “We “People don’t always appreciate the
recaptures. Adult snakes have a small take the new GPS coordinates, so we fact there are some really important
PIT tag inserted under their skin (the can learn about its movements, but species in their own regions that
same type of microchip used in dog we wouldn’t be able to get any other are endangered,” adds Faust. “It’s
and cat identification tags). Newborn data off the animal,” explains Eric not just lions in Africa that warrant
snakes, for whom PIT tagging would be Hileman, assistant research professor at conservation.”
too invasive, are marked with medical Mississippi State University, who serves
cautery units, which put a unique as the EMRSSP’s quantitative ecologist. To learn more about the EMRSSP, visit www.
number on each snake’s belly, similar to “With young snakes, however, their rate emrssp.org. For more info about the Edward
tiny tattoos. of growth is very rapid, so even a week Lowe Foundation, visit www.edwardlowe.org.
Distinguishing the eastern massasauga from look-alikes
I n Michigan there are several other regional species that appear
similar to the eastern massasauga, such as the northern water
snake, eastern fox snake, milk snake and hog-nosed snake.
Although these species lack rattles, they can produce a buzzing
sound similar to a rattle if found in leaf litter.
How to tell the real McCoy? Here are a few characteristics
that distinguish the massasauga from its Michigan mimics:
• Medium-size, thick body (24 to 36 inches in length).
• Segmented rattle at the end of its tail.
• Triangular head.
• Large heat-sensing pits or openings between
the nostrils and the eyes.
• Gray, gray-brown or brown background.
• Dark brown rectangular blocks down the back; two burrows located in wetland areas. Yet the snakes have been
or three additional rows of dark spots along its sides known to use rock crevices, holes created by rotted tree
with alternating dark and light bands along the tail. roots, submerged trash and barn floors. Massasaugas usually
return to the same site each year and hibernate alone or in
Massasaugas usually hibernate in crayfish or small-mammal small groups of two or three.
Copyright © 2021 by the Edward Lowe Foundation
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