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A study on scat:
How predator distribution and diet varies across different habitat types
Stephanie Tang
INTRODUCTION
Predators play an integral role in communities by keeping prey numbers in check and
promoting the growth of primary producers. Limiting the population growth of grazers can have
beneficial effects to the rest of the surrounding ecosystem. An illustrative example comes from
Yellowstone, where gray wolf predation on elk reduces browsing on young trees. One study
found that cottonwood tree regrowth declined in areas where wolves were extirpated, which
resulted in much higher rates of grazing related to increasing elk herd size and reduced
movement (Beschta 2005). Another example is the top-down effect of sea otters on sea urchin
populations in kelp forests. Sea otters in southern California prey on sea urchins and prevent
urchin populations from decimating kelp forests, increasing kelp productivity and biodiversity
(Pearse 2006).
Large predators are generally most vulnerable to direct anthropogenic threats such as
hunting due to their need for expansive ranges and competition with livestock, and many species
have thus suffered population declines in areas close to human development and activities. Other
indirect anthropogenic effects such as climate change have harmful bottom-up impacts on
predators because of prolonged drought stress on primary producers and resulting dwindling
populations of grazers. It is crucial to understand how predators are currently responding to a
changing climate and related impacts, so that conservationists can implement conservation
strategies to ensure optimal predator survival.
The relative rarity of large mammalian predators in an ecosystem is attributed to their
high energy demands as top predators of food webs (Ripple et al. 2014). Movement in a food
web results in a loss of energy in each successive trophic level and results in “degraded,
dispersed, and diminished…energy within a food chain” (Odum 1988). Detecting these predators
and analyzing their ecological impacts on a community may be difficult to directly measure
because of their relative scarcity compared with the abundance of herbivores and primary
producers. A useful proxy for collecting predator occurrence data is scat sampling. Scat provides
valuable information about an animal’s diet, habitat distribution, and abundance in a given area
and does not require one to follow an animal throughout its habitat. Scat analysis also is much
less intrusive and expensive than radio collar technology. One study compared scat detection
dogs, cameras, and hair snares and reported that scat detection was the most effective method to
collect data on carnivore occurrence, distribution, and abundance (Long et al. 2010). Scat
samplings saves time and money, and is much safer for both researcher and animal than a more
hands-on approach of directly pursuing predators.
We examined predator occurrence, habitat use, and diets in a California wilderness area
by collecting primarily bobcat, mountain lion, bear, coyote, and fox scat. We collected scat along
the roads and trails at Sedgwick Reserve to study carnivore distribution and prey composition in

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relation to habitat type (oak savannah, grassland, chaparral, oak woodland, and pond). The data
that we collected in the field allowed us to study the correlation between predator distribution
and diet and the locations the scats were found. The information gathered from this study helped
determine predator diet composition and predator habitat preference. Because the prey of these
carnivores also have varying ranges, we expected diet composition to also differ among the
different location types.
METHODS
STUDY SITE
We conducted this study at Sedgwick Reserve (34°69’28” N, 120°04’06” W) in the Santa
Ynez Valley of Santa Barbara County in California (Figure 1a). The reserve is one of the thirty
nine Natural Reserve System sites managed by the University of California campuses and
primarily consists of oak woodland, savannah, chaparral, and annual grassland habitats. These
habitats support a diverse range of animal species including deer, ground squirrels, skunks,
bobcats, mountain lions, coyotes, foxes, and bears. We started this study on July 1 and concluded
on July 10.
STUDY DESIGN
Figure 1(a). Sedgwick Reserve is located in Santa Barbara County in the Santa Ynez Mountains.
Figure 1(b). The map on the right shows the trails on which we traveled and each species’ scats collected.

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Our 6-person research team traveled along the trails in grassland, chaparral, oak
savannah, woodland, and pond habitats to find and collect scats (Figure 1b). We collected every
carnivore scat sample we found and recorded the date, habitat type, species, general location,
relative age of scat (fresh, mid, old), and GPS coordinates. After collection, we further analyzed
the scats and their contents. We first used an electronic caliper to measure and record the length
and width of the largest continuous scat and then dissected the scats, noting their general
contents (fur, bones, arthropods, scales, feathers, and plant matter). We used the Field Guide to
Animal Tracks and Scat of California by Mark Elbroch, Michael Kresky, and Jonah Evans to
help identify each species’ scats. We discussed scats of unknown identity and reached a general
consensus for final determination of species. Scats that could not be identified after discussion
were thrown out as lost replicates and not included in our data. After scat collection and analysis,
we input the GPS waypoints into ArcMap (ESRI 2016) and overlaid them onto a map of
Sedgwick Reserve to visualize patterns of varying scat abundance in certain habitat types.
On July 2, we set up four camera traps where we found numerous scat scamples to
capture photographs of predators across different habitats within Sedgwick Reserve. We allowed
six days to pass and collected the cameras on July 8 to save photos of wildlife. After saving these
photos, we set up the cameras in new locations and allowed another three days to pass before
collecting the second set on July 11. Predator photos supplemented our scat data and further
allowed us to find correlations between predator densities and certain habitat and soil types. The
cameras were placed facing either north or south to avoid sun glare and to ensure clear images.
After installing the cameras, we recorded the GPS location of each one so we could also input
their locations into ArcMap.
STATISTICAL ANALYSIS
We input recorded data (species, scat content, prey richness1, and habitat type) into JMP
statistical software and conducted a chi-square test for scat species and habitat. We also
conducted two one-way ANOVA tests for prey richness by scat species and prey richness by
habitat. Lastly, we input the GPS waypoint data into ArcMap to visualize all the predator scat
distributions throughout Sedgwick Reserve.
RESULTS
We collected and identified a total of 230 scat samples from 5 different habitat types:
chaparral, grassland, oak savanna, oak woodland, and pond. The majority of scats found were
from bobcats, and the lowest abundance was from striped skunks (Table 1).
1 Prey richness does not include plant matter found in the scats because we wanted to know the richness of
animal prey species in the predators’ diet compositions. We also believed plant matter found in bobcat
and mountain lion scats were primarily accidental.

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Species Scat Count
Bobcat (Lynx rufus) 81
Coyote (Canis latrans) 59
Mountain Lion (Puma concolor) 34
Gray Fox (Urocyon cinereoargenteus) 28
Black Bear (Ursus americanus) 15
Raccoon (Procyon lotor) 8
Striped Skunk (Mephitis mephitis) 5
Table 1. Frequency of collected scats and their respective species
We found that certain species’ scats were significantly more likely to be found in certain
habitats and were not randomly distributed (n=230, df=24, , χ2=69.150, P<0.0001; Figure 3).
We found that prey richness varied significantly with scat species (n=226, F=10.8472,
P<0.0001; Figure 4). Prey richness also varied significantly with habitat type (n=226, F=4.1918,
P=0.0027; Figure 5).
Abundance of Species’ Scats
Frequency of Species’ Scats by Habitat
Figure 2. Scat frequency by species among the five sampled habitats. Data represent total number of scats
collected over a five day sampling period.

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Figure 3. Chi-square test displaying detected scat per species by habitat. Contingency table displays scat
species proportion in relation to habitat type. The number of scat detected per species are significantly
differently distributed in each habitat (n=230, df=24, χ2
=69.150, p<0.0001).
Scat Species by Habitat
Prey Richness by Scat Species

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Figure 4. One-way ANOVA test shows prey richness in scat varies significantly with predator species
(n=226, F=10.8472, P<0.0001). Horizontal lines in diamonds indicate mean values and upper and lower
lines indicate confidence intervals.
Figure 5. Prey richness varies significantly among habitat type (n=226, F=4.1918, p=0.0027).
The camera traps captured fox, bobcat, and coyote images exclusively at night (Figure 6).
Figure 6. Gray fox (left) and bobcat (right) images captured by camera traps in early July, 2016 at the
Sedgwick Reserve, Santa Barbara County, California.
Prey Richness by Habitat

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DISCUSSION
Overall, predators in Sedgwick Reserve did not use each habitat type equally and showed
significantly different preferences for certain locations over others (Figure 3). Bobcats occurred
most frequently among all predators in chaparral habitats while mountain lions appeared to
prefer oak savanna and grassland habitats. There was a strong distributional overlap in grassland
and oak savanna use among mountain lions, coyotes, and gray foxes. This overlap was
interesting because we did not expect competing predators to share territories. One explanation
for this phenomena is the temporal separation in each predator species’ habits: coyotes tend to be
diurnal, foxes and bobcats nocturnal, and mountain lions crepuscular, being more active during
dawn and dusk (Suttle 2016). This temporal separation may be linked to niche differentiation in
which each predator species possesses different hunting strategies to maximize hunting success.
The camera traps further supported the notion of temporal separation; the photographs of a fox
and bobcat were captured at night (Figure 6).
One interesting observation was that bears occurred exclusively in high elevation
habitats. Unlike all of the other predators, which had overlapping ranges and seemed to be found
in varying distributions in most other habitats, bears were only found in the northernmost higher
elevation areas of the reserve. One study showed that bears selected habitats away from open
roads and human settlements, and that availability of foods did not have any significant limiting
factor on their density in other habitats (Ciarniello et al. 2007). This suggested that direct human
threats such as car strikes and hunting had great influence on bear habitat preferences, and
deterred bears from selecting habitats close to human settlements.
The niche differentiation and varying hunting strategies among these predators and
preference for more open habitats (oak savanna and grassland) related to that of African lions
(Panthera leo). One prey species, zebras (Equus quagga), stayed in open grassland after
encountering lion predation near water holes, causing lions to then select grasslands and open
bushlands during the day (Courbin et al. 2015). The high abundance of predators in Sedgwick in
open areas seemed to resemble this same pattern, and suggested that there are a lot of prey
species within these open systems as well.
The methods used in this study were not completely reliable; several factors and
assumptions may have caused some errors. Identification errors were highly possible; we did not
have a lot of experience identifying species based on scats. Secondly, we started this study with
the assumption that there would be an equal distribution of scats found along both roads and
trails. Thirdly, we did not design a very systematic approach of planning which trails and how
much distance we should have traveled. Therefore, we could have had a skewed number of
samples on trails that were traveled more frequently than others. In future studies, we will need
to plan and record travel distance and spend more time learning how to identify scat species.
Future studies could be done in different temporal scales such as season and year. It
would be interesting to see the results from a cooler season and non-drought year; we would
probably see a higher abundance of scats and different scat composition. If DNA analysis were

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available, we could use it to determine the exact species of each scat, the prey contents, and
number of individuals in the reserve (Hare et al. 2016).
The results of this study provided valuable information on carnivore habitat use and prey,
and revealed the many trophic interactions within the community. This information allowed us to
recommend conservation efforts based on predator hunting strategies and behavior as well as
their habitat preferences. Because these carnivores appeared to be highly distributed among more
open habitats such as oak savanna and grassland, we can strive to protect these types of lands and
the prey species that inhabit them. Our research showed that scat sampling is an extremely
effective way to collect crucial data on carnivores and in conjunction with more rigorous prey
studies and perhaps even genetic ID techniques, scientists and conservation biologists can work
together to understand predator use across large regions with increasing anthropogenic
influences.

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