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190 IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 KAPFER

Bullsnakes (Pituophis catenifer sayi) are arguably the most impressive snakes in the upper midwestern United States.



When herpetologists weigh their options for new study
locales, the upper midwestern United States (UMUS)

does not leap to mind. This is particularly true of Wisconsin,
which might evoke visions of Holstein cattle and knee-high
snow for six months out of the year. To those who were born in
warm climates, the “Badger State” might as well be the North
Pole — certainly not a destination for herpetofaunal research.
Also for this reason, graduate students in herpetology searching
for tiny bits of space or funding to eke out an academic existence
do not first cast their eyes northward. In addition to the cold,
they perceive a lack of herpetofaunal diversity, which is true
when compared to the tropics. However, the UMUS has a nice
number of native species (I like to say a “manageable” number1),
about many of which surprisingly little is known. Couple this
with the fact that, for many of these species, the UMUS repre-
sents the periphery of their geographic distributions and an
intersection of various habitat communities, interesting research
questions start coming to mind. Therefore, conducting herpeto-
logical research in the UMUS (or, specifically, Wisconsin) can
be a rewarding endeavor for those who pursue it.

Snakes are the most speciose group in this region, with
slightly over 20 native species occurring here. Of these, the sub-
family Colubrinae is largest, represented by six species: Smooth
Greensnakes (Opheodrys vernalis), Racers (Coluber constrictor),
Eastern Milksnakes (Lampropeltis triangulum triangulum),
Western Foxsnakes (Pantherophis vulpinus), Gray Ratsnakes
(Pantherophis spiloides), and Bullsnakes (Pituophis catenifer sayi).
Among the true constrictors in this sub-family, Bullsnakes are
arguably the most impressive in stature, often exceeding 5 ft
(~150 cm) in snout-to-vent length (but I’ve received uncon-
firmed reports of 8 ft, or 240+ cm, individuals in Wisconsin).
While this may not sound impressive to those who are fortunate
enough to study boas and pythons, in a region where people

mostly encounter gartersnakes that are less than a foot (~30 cm)
in length, a five-foot plus snake is impressive.

The distribution of the Bullsnake in North America once
was vast. In fact, members of the genus Pituophis have a historic
range that covers much of the United States, from the eastern to
western coasts, north into Canada, and south into Mexico.
Bullsnakes are the most widely distributed species within this
group, and their range encompasses most of the Great Plains
Region and a portion of the Midwest. The Great Plains Region
once was dominated by prairies and grasslands, and this habitat
has become synonymous with Bullsnakes and Gophersnakes.
Much of this habitat has been converted to agriculture since the
time of European settlement, and, because of this, Bullsnakes
now are most often associated with agriculture and the rural
landscapes where they persist. In fact, the Bullsnake is often
referred to as a “friend of the farmer” because of the voracity
with which it consumes rodents. As early as 1926, Hisaw and

Chasing Bullsnakes (Pituophis catenifer sayi)
in Wisconsin: On the Road to Understanding

the Ecology and Conservation of 
the Midwest’s Giant Serpent

Joshua M. Kapfer

Senior Environmental Scientist and Wildlife Biologist
Natural Resources Consulting, Inc.

209 Commerce Parkway
Cottage Grove, WI 53527

Photographs by the author except the facing page and where indicated.

IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 191BULLSNAKES IN WISCONSIN

�

A map outlining habitat types available to radio-tagged Bullsnakes
within the author’s southwestern Wisconsin (USA) study area from
2003 to 2005 (permission to use copyrighted material granted by the
American Society of Ichthyologists and Herpetologists).

1 Wisconsin has 22 species of snakes, 11 species of turtles, four species
of lizards, and 19 species of frogs, toads, and salamanders.



Gloyd reported on this species’ ability to control “injurious”
rodents and, more recently, Rodríguez-Robles (2002) reported
that mammals such as pocket gophers, mice, and ground squir-
rels make up 75% of the diet. Unfortunately, this association
with agricultural habitats often leads to mortality, as Bullsnakes
spending an appreciable amount of time in agricultural fields
often are killed inadvertently by farm equipment (see below and
Kapfer et al. 2008a).

Despite their nearly pan-geographic distribution in North
America, their importance in rodent control, and reported
declines in several Midwestern states, relatively little research has
been conducted on members of this genus. Although some stud-
ies have focused on habitat selection and movement patterns of
Great Basin Gophersnakes in Utah, California, and British
Columbia (Parker and Brown 1980, Shewchuk 1996,
Rodríguez-Robles 2003) and the Northern Pinesnake in
Tennessee and Florida (Gerald et al. 2006a, 2006b; Burger and
Zappalorti 1998), the Bullsnake has received less attention. Until
recently, the most thorough research on habitat associations and
movements of this species had been conducted by Fitch (1999),
who spent 50 years studying an entire snake assemblage in
Kansas, and an unpublished report from Nebraska by Fox
(1986), whose goal was to control snakes that were eating water-
fowl eggs on a wildlife refuge. With the exception of Moriarty
and Linck (1998), no studies of their ecology in the Midwest
had been conducted. Although interesting, this study focused
on the movement patterns of transplanted Bullsnakes that had
been re-introduced into a recreated prairie, and the results may
not be indicative of natural populations.

In Wisconsin, Bullsnakes are known primarily from dis-
junct populations in the southern and western parts of the state.
Many factors are believed to have contributed to the decline of
this species in the UMUS. Likely explanations include loss of
preferred habitat via conversion to agriculture or encroachment
of woody vegetation and mortality due to anthropogenic causes.
Only a handful of Bullsnake sites in Wisconsin are found on
public land, to which access for research is easily granted. Few
of these sites control vegetative succession (invasion of grasslands
by woody vegetation resulting from fire suppression), and the
persistence of Bullsnake populations at such locations remains
uncertain. This, coupled with their rarity in the state, makes

them a difficult species to study if one hopes to achieve the large
sample sizes necessary for conclusive results.

The Evolution of a Graduate Student Project
In 2002, my master’s research at the University of Wisconsin-La
Crosse was drawing to a close. At that time, I remember becom-
ing intensely interested in the colubrine snakes of Wisconsin.
Prior to that, I had focused my attention on the survival of tad-
poles in agricultural ponds. However, even while collecting data
for that research, I recall spending a substantial amount of time
digging through piles of debris and flipping cover-boards in
hopes of finding a snake or two at my study sites. Although I had
enjoyed my research on frogs, my interests obviously were shift-
ing. Soon, I was scouring literature databases for published infor-
mation on colubrine snakes in the upper Midwest … and find-
ing very little beyond what was contained in field guides. Clearly,
this was the avenue I wanted to pursue as a researcher. Most
snakes in this group were interesting ecologically, research on
them was uncharted territory in the UMUS, and, most impor-
tantly, they were big constrictors (and big equals more fun in my
book). Of species native to the region, the biggest (and therefore,
likely to be the most fun to research) was the Bullsnake.

Looking back, I realize that I had been fortunate as a gradu-
ate student. I wanted to conduct research on Bullsnakes, but that
was only half the battle. I needed a home at a university, a gradu-
ate advisor, and funding (for my research and to pay my bills).
Luckily, I was able to convince Dr. James Coggins at the
University of Wisconsin-Milwaukee that, although he was a par-
asitologist by trade, he really needed to take on a wannabe her-
petologist as a grad student. I also had the support of the
Wisconsin Department of Natural Resources, Bureau of
Endangered Resources Herpetologist Bob Hay (an outstanding
field herpetologist), who proved a source of excellent advice on
countless occasions. In addition, Dr. Erik Wild, a herpetologist I
had known for several years from the University of Wisconsin-
Stevens Point, agreed to be an adjunct member of my graduate
committee, for which I am forever grateful. Had these three indi-
viduals not been willing to be a part of my research, it would not
have happened. On the downside, I would have to conduct my
research on a very tight budget. I was able to acquire small grants
that covered transmitters and implantation, PIT tags, and a GPS

192 IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 KAPFER

This male Bullsnake was the first snake captured and implanted with
a transmitter.

This Bullsnake was the only female that survived all three years of
radio-telemetry research.



IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 193BULLSNAKES IN WISCONSIN

unit. The rest was borrowed or out-of-pocket, but I didn’t care —
I was going to conduct research.

In the spring of 2003, I began work in southwestern
Wisconsin, an area associated with the “Lower Wisconsin River
Valley.” At the time, I decided that radio-telemetry, a well-estab-
lished method for studies of snake ecology, would be employed
to track snakes for three years. Prior to this research, I had been
involved in a USGS radio-telemetry study on Leopard Frogs
(Lithobates pipiens) in Minnesota, and had learned the subtleties
of using the technology, which seemed (and still seems) to be the
best possible option for elucidating detailed information about
the habitat selection and movement of such secretive critters.
With help, by April of ’03 I had found a site likely to yield
enough snakes to make good use of the transmitters I could
afford (approximately 20).

The first day of fieldwork was quite an experience. Bob
(Hay) and I went to the study site in late April, hoping that the
snakes had started to emerge from hibernation. We began walk-
ing across the prairie on a cloudy day and after only 15 or 20
minutes, I heard Bob say, “There’s one, right there!” Sure
enough, moving across the edge of a sandblow was a beautiful
male Bullsnake. We were both pretty excited. Those who study
amphibians and reptiles know that you can spend hours or days
searching for some species and not find a single individual.

With our first snake in the bag, we split up. I went west,
scouring brushy hillsides, and Bob went straight ahead, toward
a more open hillside. As I worked over the slope, I occasionally
glanced over at Bob to see if he was having any luck, but never
got the feeling that he was finding anything. “That’s alright,” I
remember thinking to myself, “If I can catch one snake every
time I come out here, I’ll still have a decent sample by May.”
About an hour later, we met in the middle on a large open hill-
side, with exposed rocky shelves and outcroppings around us.
For a few minutes, we considered quitting. What we didn’t real-
ize was that things were about to get very busy. After deciding
that we shouldn’t give up so easily, we both started poking
around brushpiles on the hillside where we had met. Within
minutes we found another snake — a big one, then another. A
few minutes later, we found yet another. I was amazed at how
our luck had changed! We could hardly get the pillowcases ready
fast enough to hold one snake before finding another. All in all,

our day ended with eight Bullsnakes captured and ready for
transmitter implantation. What a great start for the research
project! At that time, I had no idea how fortunate we had been.
Later I was to learn just how difficult these snakes are to find.

Bullsnake Populations and Sources of Mortality
That first year (2003), I ended with 21 adult Bullsnakes with
implanted transmitters. This included the eight found on the first
day of the study and four found with help from a UW-Madison
Vertebrate Zoology class of approximately 50 students. This
would be my most productive year for finding new snakes. In
2004 and 2005, I found 20 and 15 individuals, respectively. The
most troublesome part of this decline in the number of new
snakes was that females were encountered less frequently than
males. In general, despite the large number of snakes caught that
first day, Bullsnakes were not very abundant at this site, and I esti-
mated a density of only 0.42 adults per hectare at the end of the
study. Recapturing snakes without the aid of telemetry equipment
also was very difficult. The low number of recaptures with only
one surveyor present (i.e., me) made it unlikely that an adequate
estimate of population size could be made. Only with the help of
the UW-Madison students was I able to get recaptures within a
reasonable amount of time. My only consolation was that low
recapture rates in snakes of this genus are not uncommon (Fox
1986, Diller and Wallace 1996, Shewchuk 1996, Fitch 1999).

Bullsnakes face numerous daily pressures in addition to the
long-term loss of suitable habitat. Traffic, farm equipment, wan-
ton killing by unknowing landowners, and (I found during my
research) predators all pose significant threats (Kapfer et al.
2008a). When I began tracking Bullsnakes in ’03, I felt confi-
dent that few, if any, natural predators would consider taking an
adult snake. I was fairly certain that birds of prey probably con-
sumed juveniles and numerous predators likely ate hatchlings.
However, I never believed that mammalian predators (such as
coyotes) would be much of an issue, thinking that more abun-
dant prey would result in a greater caloric payoff per unit effort
than snakes. In fact, on numerous occasions, I saw coyote kill
sites containing the remains of rabbits, turkeys, pocket gophers,
and even deer. However, my assumptions were incorrect. In one
year (2004), nearly all of the snakes consumed were taken by
coyotes. Most of this mortality corresponded with heavy spring

The author holds a male Bullsnake, the largest individual tracked dur-
ing the study. Unfortunately, it was killed and eaten by a coyote.

This female was killed by a plow during the crop harvest in early fall
2005.



rains, which Jackson (1961) suggested could result in higher
than normal leveret (= baby rabbit) mortality due to exposure.
Could this have caused coyotes to shift from a preferred prey of
rabbits to snakes? Possibly, but without having examined prey
availability more closely, I can’t say for certain.

In 2003 and 2005, farm equipment was, by far, the great-
est cause of mortality in radio-tagged snakes, with females invari-
ably experiencing higher mortality rates than males. In fact, in
all three years pooled, the mortality rate for females with
implanted transmitters was nearly 44%, compared to 14% in
males (and nearly 27% for all snakes). Furthermore, most of the
females taken by coyotes were gravid and likely killed prior to
egg deposition, which is not a good omen for the persistence of
these snakes in the region.

I did find that, despite equipment-related mortality, most
local farmers were sensitive to this species. Many actually liked
having Bullsnakes around, due to their effectiveness as rodent
predators. Several of the local landowners actually accompanied
me when I tracked my test subjects, hoping to get a look at them
and see exactly what I was doing. Yet, agricultural equipment
posed a definite threat to Bullsnake survival at this site. I found
it strange that, despite the presence of suitable non-agricultural
habitat readily available to the snakes I was tracking, many ven-
tured into agricultural fields and often died. Considering my low
Bullsnake density estimates compared to apparently abundant
prey, competition for food seemed an unlikely reason for them
to enter agricultural fields. Regardless, the tendency of this
species to enter a burrow when danger approached did not save
them from the digging tines of equipment used to harvest crops.
Although most of the local farmers would not actively harm
Bullsnakes, snakes hidden in burrows below crops were inadver-
tently killed by plows on several occasions.

Preferred Habitat and Movement Patterns
Aside from determining sources of mortality, a principal goal of
my research was to document movements and habitat selection.
The best available information on preferred habitat of this snake
in Wisconsin was anecdotal, and came from Richard C. Vogt’s
(1981) field guide, Natural History of Amphibians and Reptiles in
Wisconsin (Milwaukee Public Museum Press). Because
Bullsnakes are considered rare or declining in several states in the
UMUS (i.e., Minnesota, Iowa, and Wisconsin), a rigorous study
on preferred habitats and movement patterns was necessary to
facilitate their conservation.

Generally, this species is reported to prefer open canopy,
short-grass prairie, or grassland habitats. I believed that these
would be the habitats selected by the snakes I was tracking as
well. The result of my research, however, was not so cut-and-
dried. Throughout the year, I located individuals in habitats that
I would never have imagined them using. For example, on more
than one occasion, I followed individuals through dense under-
brush in closed canopy hardwood forests on bluff sides (not a
desirable task in the high humidity, 90°-days of July or August).
I found later that these habitats were not preferred when their
availability was considered (combined with agriculture, they
equaled nearly 65% of the available habitat). This was not ter-
ribly surprising. What did surprise me, however, was that the
traditional Bullsnake habitat (i.e., prairie and grassland) also was
not preferred when based on its availability. 

The habitat that was preferred by males and females in all
three years of the study was open canopy, south- or west-facing
bluffs. This was despite the fact that this habitat comprised only
~3% of available habitat (Kapfer et al. 2008b). Communal den-
ning sites often are found on exposed bluff slopes such as these,
so I had previously believed this habitat would be important to
the Bullsnakes only immediately before and after winter dor-
mancy. I had not anticipated that it would be used by snakes
more than other available habitats in every season.

What I believe is important regarding my results on habi-
tat preferences is that most long-term plans for prairie habitat
management with which I have experience seem to focus mostly
on eliminating woody vegetation (even native species, such as
oaks) in flatland habitats. While helping native herbaceous

194 IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 KAPFER

Snakes frequently came into contact with humans. This individual
was found near a farmhouse and might have been killed if the
landowner had not been sympathetic toward snakes.

D
A

N
 N

ED
R

EL
O

Table 1. Comparison of the percentage of the study site com-
prised of different habitats and proportion of total snake loca-
tions occurring in each habitat type.

Habitat Type Percent Snakes Percent Availability
in Habitat Types of Habitat Types

Bluffside Forest 10 37
Row Crop 7 28
Flatland Forest 4 5
Pasture 3 5
Roadside 2 2
Edge (ag/nat) 6 3
Open Grassland 13 7
Oak Savanna 15 6
Open Bluff 33 3



IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 195BULLSNAKES IN WISCONSIN

prairie vegetation proliferate is obviously important, a habitat
with greater structural heterogeneity might be of greater value
to wildlife — including reptiles, for which the elimination of
woody vegetation tends to eliminate thermoregulatory oppor-
tunities. Ground temperatures on sand prairies are very high and
often exceed 50 °C (pers. obs.). Although some reptiles may be
able to tolerate such temperatures, I found that the average
ground temperature where I observed Bullsnakes ranged from
29.8–30.7 °C (with body temperatures of 25.2–26.7 °C; Kapfer
et al. 2008c).

Very open, short-grass habitats also contain fewer types of
refugia from predators. Bullsnakes, for example, often were
observed seeking shelter in fallen oak trees, brushpiles, or tan-
gles of native woody vegetation (e.g., raspberry). If large expanses
of such open flatland habitat are the goal for habitat managers,
maintenance of edges or savanna-type habitats should also be
considered. These can create refuges and movement corridors
for wildlife. Regardless, in the UMUS, open south- or west-fac-
ing bluffs are critical habitats for this species. Therefore, clearing
these slopes, if they are present on a particular site, may be nec-
essary for the persistence of these snakes.

Understanding the spatial ecology of this species is also
important for their conservation. For example, knowing the dis-
tances that individuals travel or the areas they typically patrol
during the active season can provide insights into the critical
sizes of habitats that should be preserved. Something that
became apparent early in the study was that these snakes are
capable of moving long distances. On average, individuals
moved nearly 35 m/day (Kapfer et al. 2008b). They also
patrolled large home ranges. I measured home range using two
different methods: (1) Minimum convex polygons are deter-
mined by simply connecting the outermost locations of an indi-
vidual on a map, which then becomes the boundary of its home-
range; and (2) Kernel estimates use the density and spread of
location points for a radio-tagged individual as if they were plot-
ted on a histogram, resulting in a greater proportion of the home
range centered around areas where the highest density, or inten-
sity, of locations occurs. Isopleth lines are generated, based on
relative intensity of point concentrations, which allows core areas
of the home range to be delineated. With this method, one can
estimate the area that the animal is likely to patrol, while elimi-
nating locations determined to be outliers. Minimum convex
polygon home ranges ranged from 20 to nearly 50 hectares in
tracked snakes, whereas kernel estimates for the same snakes
ranged from 40–95 hectares. Both methods, however, indicated
that these snakes moved about in large areas, suggesting that very
large habitat preserves might reduce travel into agricultural fields
or across roads, where mortality is high.

Although I rarely found snakes in the same location in sub-
sequent observations, they often returned to the same locations
after varying periods of time, resulting in a high fidelity for spe-
cific spots within their home ranges. This has obvious conserva-
tion and management implications: (1) Snakes that return to the
same spots frequently may be accidentally killed during intense
management practices (i.e., burning or cutting of undesirable veg-
etation that are conducted at the same locations annually); and
(2) unscrupulous snake collectors can have a profound effect on
Bullsnake populations by checking the same locations annually.

Finale
The following example of this species’ tendency to end up in
strange places also illustrates how the unpredictable nature of
field research generates a need for future exploration of observed
phenomena. This particular event came on a day when a friend
of mine (Tim Muehlfeld) and I were tracking a male Bullsnake
around a farmhouse. I had heard the snake’s signal in the vicin-
ity two days prior, but had not yet been able to ask the
landowner for permission to enter his property. On this day,
however, we did talk to the gentlemen who owned the property,
and he was very willing to let us track the snake. I told him that
it might be near his house and he seemed to become even more
eager, wanting the snake moved so it would not scare his wife.
We obliged and began searching for this snake’s signal around the
house’s foundation, but I was surprised to find that the signal was
very weak unless I pointed the antenna almost straight up.

At first I thought the snake might have moved to the back-
yard, and the signal became slightly stronger when we made our
way around to the back of the house and into the entrance to
his garage. I wondered if the snake was in the garage, behind the

Snakes might be attracted to agricultural fields because winter-wheat
fields look like grasslands in early spring. Tim Muehlfeld is an enthusi-
ast and a good friend who assisted the author on numerous occasions.

Bullsnakes have a unique pattern unlike that of any other snake in the
midwestern United States.



garbage cans, or in a corner hunting rodents, but the signal
seemed to be overhead. Not only was it overhead, it grew
stronger as we moved toward the entrance to his house from the
garage. I could tell that the landowner was uncomfortable with
the thought of the snake being in his house. He looked at us and
said, “Do you want to go inside the house?”

Within minutes, and after removing our dirty field shoes,
we were cautiously moving about his living room in our stock-
ing feet (I have to admit, it felt strange having to worry about
breaking ornamental glassware with a telemetry antenna, which
was something I never thought I would have to consider during
my research). The signal strength quickly guided us to the upper
level of the house, down a hallway, and into the bathroom. My
first thought was “you’re kidding! This snake is actually going to
be in the toilet — the urban legend will come to life before our
eyes!” Fortunately, that was not the case. What we did determine
was that the signal was higher still, and strongest in a small area
of the ceiling directly above the shower. The landowner immedi-
ately turned to me and asked, “Do you want to go into the attic?”

So, with him as our guide, the three of us marched to a lad-
der that led to a small rectangular opening in the ceiling of his
home. Upon entering the attic, Tim and I shared the same feel-
ing of dread. It was incredibly hot and not at all what I imag-
ined a place where I would find a Bullsnake to be like. My first
thought was that the animal had been eaten by a raccoon, which
had swallowed the transmitter and was now in this man’s attic.
Looking back on it, such a scenario was as unlikely as us find-
ing a Sasquatch, but strange things come to mind when you’re
in bizarre situations.

The next problem was that the attic was pitch black and
not a “finished” room. We had to walk across cross beams
between which insulation had been packed. Wearing only socks,
balancing on narrow wooden beams in the dark, and holding a
large telemetry antenna, I attempted to locate the snake in the
beam of two small flashlights. The increasingly strong transmit-
ter signal told us that the snake (or at least its transmitter) was
somewhere in the attic.

Trying to get my bearings in the dark, I swung the antenna
to the left and the signal got stronger. “It’s somewhere over
there,” I said. “We’ve got to get this snake out of here before my
wife gets home,” the landowner replied uncomfortably. So, care-
fully stepping on crossbeams and grabbing anything overhead
that we could use to stabilize ourselves, we moved in that direc-
tion. As the roof sloped downward, we noticed a long crack that
allowed a small amount of light into that corner of the attic and,
upon our arrival, saw a small group of birds make a hasty exit
through the crack. At that point, I knew if that crack was large
enough for birds to get in, it was large enough for a snake —
and maybe we weren’t looking for a dead snake after all. Then
Tim spoke up: “I see it,” as the beam of his flashlight rested on
a Bullsnake coil, barely visible in the insulation. “Can you grab
him?” I asked, as my hands were full and Tim was closest to the
snake. He leaned against a nearby support beam so that he was
almost vertical and snatched up the visible coil. He later con-
fessed to me that he was certain the snake would be “mush” in
his hand when he grabbed it (i.e., he’d be grabbing the decaying
body of a dead snake). On the contrary, the second he laid a fin-
ger on the animal, it instantly curved its neck into a defensive
posture and hissed loudly. It was alive and, we determined later,
in perfect health.

The man asked me to remove the snake from his property.
Although I was reluctant to do this, as it would confound the
data I was collecting, he had been pretty understanding about
the whole incident. So, I moved the snake nearly half a mile (0.8
kilometers) away and released it within its normal home range.
A few days later, however, I discovered that the snake had obvi-
ously known where it wanted to be. It had returned to this spe-
cific property again, and was resting comfortably in the hollow
of a maple tree along the landowner’s driveway.

I’ve always wondered what that snake was doing in that hot,
stuffy attic. Eating baby birds? It was too dark to see if any nests
were present. What was a “prairie” snake species that is not
thought to be very arboreal doing in the attic of a farmhouse?
How did it find enough purchase on the house’s exterior to climb
up there? Was the attic part of its normal home range (it never
did return to the attic)? I have no answers to these questions, but
a desire to find such answers (in other words, curiosity) drives

196 IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 KAPFER

An open bluff used by Bullsnakes in the upper Midwest. Note also
the extensive agriculture in the adjacent flatlands.

Although snakes used this incredibly thick understory vegetation
under a dense canopy, it was used infrequently compared to its preva-
lence at my study site.



IGUANA  •  VOLUME 15, NUMBER 4  •  DECEMBER 2008 197BULLSNAKES IN WISCONSIN

those of use who choose to engage in science. Fortunately for me,
snakes seem particularly effective in raising new questions.

Acknowledgments
I thank Jim Coggins, Peter Dunn, Linda Whittingham, Jerry
Kaster (UW-Milwaukee), Erik Wild (UW-Stevens Point),
Robert Hay (WDNR), Mike Pauers (Medical College of
Wisconsin), Craig Berg (Milwaukee County Zoo), and Rich
Sajdak for advice regarding experimental design, field method-
ology, and help with data analyses. Colin Bennell, Chad
Hopper, Max Kapfer, Tom Kessenich, Tim Muehlfeld, Greig
and Bjorn Stanton, Nick Schiltz, Vannessa Torti, and Scott
Craven’s Vertebrate Zoology class (UW-Madison) provided field
assistance. Steve Richter and Paul West at The Nature
Conservancy (Madison, WI) and numerous private landowners
allowed access to their property. Jean Pare, Joanne Paul-Murphy,
Chris Hanley, Kurt Sladky, Anne Stewart, and their students at
the UW-Madison School of Veterinary Medicine surgically
implanted radio transmitters. John Laedlein (WDNR), Shawn
Weick (USGS), and Chris Pekar (Natural Resources
Consulting) provided GIS assistance. Travis Livieri, Eric
Anderson (UW-Stevens Point), and Brian Cade (USGS) pro-
vided advice on movements and site fidelity analyses. Pat

Gregory, Karl Larsen, and the Crescent Lake Wildlife Refuge
(Nebraska) provided copies of unpublished reports and theses
on Pituophis catenifer.

Funding was provided by the Society for the Study of
Amphibians and Reptiles Grants in Herpetology Program, the
Milwaukee Zoological Society, The Wisconsin Academy of
Sciences Lois Almon Foundation, The Prairie Biotic Research,
Inc. Small Grants Program, the Chicago Herpetological Society,
The University of Wisconsin-Milwaukee, Department of
Biological Sciences Ruth Walker Memorial Fund, and The
Wisconsin Department of Natural Resources-Bureau of En-
dangered Resources. Permission was granted from the Wisconsin
Department of Natural Resources to work with a protected wild
animal, and research was conducted under animal care and use
protocol (02-03 #145) issued by UW-Milwaukee.

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In addition to open grasslands, management should consider preser-
vation of Oak savanna and other habitats that are structurally hetero-
geneous and could provide refugia for wildlife.

The infamous “attic snake” nearly scared a local landowner and his
wife to death!




