camera-traps and bobcats - j.m. collins

Running Head: CAMERA-TRAPS AND BOBCATS

Camera-Traps and Bobcats: An Introduction to Field Camera

Technology as a Tool for Wildlife Conservation

Jared M. Collins - Global Field Program

Miami University – Oxford, Ohio

CAMERA-TRAPS AND BOBCATS

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Abstract

Modern field camera technology provides a quantitative approach to wildlife research that is

non-invasive, low in cost and labor, and effective at documenting and monitoring the presence of

cryptic wildlife. Essentially, a field camera is comprised of a point-and-shoot style digital

camera with a storage device, flash unit, trigger mechanism, and power supply, encased in a

camouflage, weatherproof shell that can be mounted to a tree. The purpose of this paper is to

introduce this technology and describe how camera-traps have been effectively utilized in the

context of wildlife conservation science. In addition, the Hoosier bobcat (Lynx rufus) is

introduced as a prime subject for camera-trap conservation in northern Indiana. Furthermore, the

author outlines an approach to research that recognizes strategic and systematic logistics specific

to the case of the Hoosier bobcat. The author concludes that a case-specific approach, in which

camera-traps are strategically placed within suspected bobcat movement corridors, may be the

most effective method to detect the presence of the bobcat in northern Indiana.

Introduction

Over the past few decades, the field camera, or camera-trap, has become increasingly popular as

a reliable and effective method to capture visual documentation of extant wildlife. In its most

basic form, a camera-trap is a digital camera equipped with motion sensor or infrared sensor

technology, enclosed in a protective camouflage casing. Photo-trapping with the use of a

camera-trap provides a quantitative approach to wildlife research that is non-invasive, low in cost

and labor and, most importantly, effective at documenting and monitoring the presence of highly

cryptic wildlife (O'Connell, Nichols, & Karanth, 2010). Consequently, conservation scientists

worldwide have begun to utilize this technology more frequently as a key tool for ecological

research and wildlife assessment initiatives (Rowcliffe & Carbone, 2008). Some of the many

important conservation science initiatives of the past that have utilized camera-traps include a

wide variety of baseline presence/absence inventories and biodiversity (i.e., species abundance

and richness) assessment surveys (Rowcliffe & Carbone, 2008). More recently, camera-traps

have been utilized by researchers to study the feeding behavior, activity patterns and population

dynamics of rare, wide-ranging, and/or reclusive species (O'Connell et al., 2010). Ultimately,

there is little doubt that the use of this technology has significantly improved our understanding


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of the complex ecological relationships and population dynamics of many rare and endangered

species.

Perhaps one of the most important applications of the camera-trap to date has been to document

the existence (and, subsequently, the abundance) of rare and elusive mammal species. Many of

these camera-trap studies have been focused on wild felid populations that are inherently

scattered and reclusive, and that inhabit environments of difficult terrain, where traditional forms

of non-invasive observation are problematic, if not impossible. In fact, a literature review by

Rowcliffe & Carbone (2008) has shown that "the single most common use of camera traps has

been to estimate the abundance of cat species, relying on individual recognition from coat

patterns". For instance, camera-traps have become instrumental in the documentation of felid

biodiversity in the inhospitable tropical environment of Borneo. In 2003, a camera-trap survey

in the thick rainforest of Gunung Mulu National Park, Sarawak, Malaysia, was responsible for

the first ever visual documentation of the Bornean bay cat (Catopuma badia), one of the world's

rarest wild felines (Dinets, 2003). In addition, a 17 month (May 2008 - October 2009) survey

conducted by Cheyne & Macdonald (2011) further utilized camera-traps to document the

remaining four of Borneo's five wild felid species, including the Sunda clouded leopard (Neofelis

diardi), the leopard cat (Prionailurus bengalensis), the flat-headed cat (Prionailurus planiceps),

and the marbled cat (Pardofelis marmorata). Elsewhere across the globe, camera-trap

technology and photo-trapping has been equally instrumental in detecting and/or monitoring rare

wild cat populations. For instance, since 2010, camera-traps have been used effectively to

document and monitor rare felids such as the Andean cat (Leopardus jacobita) in the west-

central highlands of South America (Reppucci, Gardner, & Lucherini, 2011), the African golden

cat (Profelis aurata) in the tropical lowlands of central and west Africa (Aronsen, 2010), and the

Iberian lynx (Lynx pardinus) of Spanish Europe (Garrote et al., 2012; Gil-Sanchez et al., 2011).

Also, camera-trap technology has played an important role in establishing the northernmost

extent of the North American range of the jaguar (Panthera onca) and the jaguarundi (Puma

yagouaroundi) in north and central Mexico, respectively (Gutierrez-Gonzalez et al., 2012;

Monterrubio Rico et al., 2012). This plenitude of evidence suggests that camera-trap technology

has become an increasingly important tool for researchers seeking to gain insight on the secret

life of wild felines. Therefore, the goal of this paper is to further examine field camera


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technology as a wildlife conservation tool, and determine how this technology might be used

effectively to detect and/or monitor the presence of the bobcat (Lynx rufus) in northern Indiana.

What is a camera-trap, and how does it work?

Camera-traps are fixed, remotely activated, digital cameras that utilize motion or heat detection

technology to capture images of passing wildlife. Essentially, each field camera is comprised of

a point-and-shoot style digital camera with a storage device (e.g., memory card), flash unit,

trigger mechanism, and power supply all encased in a protective, weatherproof shell that can be

mounted to a tree or post. Camera-traps are designed to imprint the date and time on each digital

image, and many cam-traps are equipped to take both still photographs and short video clips.

The captured footage is automatically written to an SD card where images are stored until they

can be transferred to a tablet or PC. The image storage capacity of most current cam-trap models

can be quite enormous depending on the size of memory card used (e.g., most models support up

to 32GB). Camera traps are triggered by the motion and/or heat of wildlife that comes within a

certain distance (i.e., typically 40-60 ft.) of the trap sensor, and the sensitivity of the trigger can

be adjusted to optimize use according to time of day and time of year (TrailCamPro, 2012).

Furthermore, as a result of improved battery life technology, many current cam-trap models are

capable of remaining operational for up to a year or more on one set of batteries (i.e., typically 8

AA) (TrailCamPro, 2012). Currently, camera-traps are readily available and relatively

affordable, and Amazon.com features a wide variety of Bushnell and Moultrie field cameras at a

range in price from just under $150 per unit, to over $400.

Field cameras are necessarily equipped with either an incandescent or an infrared flash device.

The difference between infrared and incandescent cameras is that the former uses infrared light

to take pictures, and this infrared flash is invisible to passing wildlife (TrailCamPro, 2012).

Most infrared camera-traps also allow for video recording at night, which is another advantage of

the infrared flash device. However, color pictures can be taken only during daylight hours, and

all night-time pictures are monochromatic contrasts (TrailCamPro, 2012). Alternatively,

incandescent cameras allow for stunning full color visuals even in the pitch-dark of the night.

The term "incandescent" refers to the traditional flash bulb device that flashes a bright light to

capture images in full color with clarity and brightness. The primary disadvantage to this


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approach is that an incandescent flash is extremely bright, which has the potential to frighten

passing animals and discourage resident wildlife from entering the observation zone

(TrailCamPro, 2012).

How can a camera-trap be used as a tool of conservation?

The observation and documentation of wildlife distribution and movement patterns is of critical

importance as a source of baseline data for a wide array of conservation initiatives (Kays et al.,

2011), and research from Gibbs (2000) has demonstrated that "population monitoring" plays a

crucial role in ecological studies and wildlife conservation initiatives (as cited in Heilbrun, 2006,

p. 69). Thus, it is not at all surprising that the camera-trap, a device specifically designed to

detect and document, has become such an important tool in the world of conservation science.

Kays et al., 2011 describe the camera-trap as a "visual sensor to record the presence of a broad

range of species providing location-specific information on movement and behavior". As a

"visual sensor" of wildlife, the camera-trap offers researchers the perfect Eulerian approach to

tracking the movement of wildlife, in which a specific location is monitored to capture the

movement of all the wildlife that passes by (Kays et al., 2011). In contrast, the Lagrangian

approach to tracking wildlife movement exists as a more labor intensive (and potentially

dangerous) approach that requires the temporary capture of individual animals for the purpose of

tagging or implanting a radio-telemetry monitoring device (Kays et al., 2011). Consequently,

cam-traps are often championed as an effective and non-invasive biodiversity assessment tool,

and this location-specific solution has quickly become a popular approach to document species

richness and abundance worldwide.

A detailed literature review covering the combined topics of "camera-traps" and "conservation

science" revealed that, over the past decade, wildlife research featuring the use of camera-traps

has primarily focused on baseline systematic assessments such as species richness surveys,

relative abundance studies and other biodiversity-related objectives. For example, rapid species

richness surveys in Malaysia and Lebanon have successfully utilized camera-trap technology to

document the cryptic wildlife of two ecologically distinct habitats. A rapid assessment survey

conducted by Mohd. Azlan & Lading (2006) in the tropical forest environment of Sarawak,

Malaysia, utilized camera-trap technology to capture visual documentation of several rare and


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elusive mammals (i.e., the binturong Arctictis binturong, the bearded pig Sus barbatus, the

Sunda clouded leopard Neofelis diardi) currently listed as Vulnerable by the International Union

for the Conservation of Nature (IUCN, 2012). Likewise, a rapid assessment survey conducted

by Abi-Said & Amr (2012) in the subtropical scrubland environment of Jabal Moussa, Lebanon

also utilized camera-trap technology to capture visual documentation of several rare and elusive

mammals, in this case revealing the southernmost extent of the range of the least weasel

(Mustela nivalis) and the Eurasian badger (Meles meles). Furthermore, camera-traps have also

been instrumental in aiding the analysis of the relative abundance and density of shy, rare and

elusive wildlife populations. For instance, a rapid abundance assessment of carnivores

conducted by Gerber et al. (2010) in the rainforest environment of eastern Madagascar utilized

camera-traps to gather, for the first time, valuable baseline data regarding the abundance and

density of the fossa (Cryptoprocta ferox) in the eastern part of its range. Consequently, their

research discovered that fossa abundance and density may be much lower in the wet forests of

the eastern half of the island, when compared to that of conspecific populations in the western

dry forests (Gerber et al., 2010). Ultimately, each of the studies outlined above have utilized

camera-trap technology to gather important bits of baseline data that will allow for more

complex ecological studies to be undertaken in the future.

Why the bobcat?: Lynx rufus in Indiana

So then, why the bobcat? What is the point of studying a wild cat population that is officially

listed by the IUCN (2013) as a species of Least Concern? Lynx rufus has a long history in

Indiana as a beneficial predator and generalist carnivore. Bobcats are entirely carnivorous, and

while they prefer to prey on rabbits, they also feed on rats, mice, moles and squirrels, as well as

woodchucks, raccoons, feral cats and even deer (Kelly et al., 2008; Whitaker & Mumford, 2009).

Bobcats have been needlessly destroyed due to the misconception that they are vicious predators,

while, in fact, they are a beneficial carnivore, effective at controlling rodent populations and

culling sick or injured deer and mesopredators (i.e., raccoons, feral cats, etc.).

The bobcat once ranged widely across the state of Indiana, however, residential and agricultural

pressures from an expanding human population have resulted in widespread deforestation and

the associated loss and fragmentation of bobcat habitat. Consequently, this loss of habitat,


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coupled with detrimental effects of trapping, sport hunting and predator control initiatives, has

resulted in a severe decline of the bobcat population in Indiana over the past century (Whitaker

& Mumford, 2009). By 1970 it became necessary to place the bobcat on the state endangered

species list and, over a decade later, a survey by Mumford & Whitaker (1982) revealed that the

"bobcat was quite rare in Indiana" (as cited in Whitaker & Mumford, 2009, p. 601). Yet, by

2005, the Hoosier bobcat population had recovered sufficiently enough in the forested hills of

southern Indiana to warrant its removal from the state endangered list. However, the reality of

extreme landscape fragmentation in northern Indiana, and the associated lack of quality bobcat

habitat, has resulted in what is essentially a bobcat-free zone across the northern half of the state

(Whitaker & Mumford, 2009). Yet, in spite of this extremely fragmented and unfavorable

environment, the bobcat's presence has been confirmed in northern Indiana on 6 occasions

(representing six individuals) since 1993 (Whitaker & Mumford, 2009). The first two

confirmations occurred in 1993 in the extreme northeastern corner of Indiana (i.e., Dekalb and

Steuben counties) (Whitaker & Mumford, 2009). The Dekalb confirmation is of particular

importance as the first confirmed report of Lynx rufus in northern Indiana since 1970. A third

confirmed report from northeastern Indiana was documented at the Pigeon River Fish and

Wildlife Area in Lagrange County in 1998 (Whitaker & Mumford, 2009). The other three

confirmed reports come from the heart of the Wabash/Tippecanoe watershed in north-central

Indiana; Fulton County (1996), Cass County (1997), and Carroll County (1999) (See Appendix I,

Map 1) (Whitaker & Mumford, 2009). In addition, many unconfirmed reports also exist,

including a 2001 sighting witnessed by the author near Goshen, Indiana (Elkhart County).

Ultimately, the singular situation of the bobcat in northern Indiana presents the perfect

opportunity to utilize camera-traps as an approach to survey an elusive and locally rare mammal.

Discussion

The preceding three sections of this paper were intended to introduce field camera technology,

describe how this technology has been utilized in the context of conservation science, and

introduce the Hoosier bobcat as a prime subject for camera-trap conservation. This final section

is intended to illustrate how field camera technology might be used effectively to detect and

monitor the presence of the bobcat in northern Indiana.


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Questions about Lynx rufus that might be answered with the help of camera-traps include: Are

bobcats in northern Indiana part of a local population, or are they transients moving between

larger populations in Michigan and Kentucky? Or, how might the fragmented agricultural

landscape of northern Indiana effectively limit the movement and interaction of the bobcat

metapopulation? As a norm, wildlife researchers look to use a variety of productive means to

estimate the distribution and abundance of a species of interest, generally utilizing both Eulerian

(location-specific) and Lagrangian (host-specific) technology. However, most host-specific

technologies (i.e., tags, collars, implants, etc.) are labor intensive, and they can be quite difficult

(and even dangerous) to use when monitoring wild carnivores that are rare, elusive or nocturnal,

not to mention unpredictable and aggressive (e.g., many wild felids). In the case of the Hoosier

bobcat, wildlife researcher Scott Johnson of the Indiana Department of Natural Resources

(IDNR) successfully utilized a Lagrangian approach (i.e., fitted radio collars) to monitor 38

individual bobcats in southern Indiana (Whitaker & Mumford, 2009). From December 1998 to

April 2005, Johnson carefully documented the distribution, density and habitat preferences of a

relict population of bobcat in south-central Indiana. By tracking, trapping and the fitting

bobcats with radio collars, Johnson gathered valuable data that would eventually be instrumental

in the development of a bobcat habitat management plan. Johnson's work revealed that while,

the bobcat of southern Indiana prefers to inhabit remote wooded areas, it is not averse to moving

about a fragmented landscape if it can find temporary refuge in swamps and wooded

bottomlands (Whitaker & Mumford, 2009). In 2005, Johnson's long-term management and

research program began to show results as the bobcat was officially removed from Indiana's

endangered species list and reclassified as a Species of Special Concern (Whitaker & Mumford,

2009).

While the future of the bobcat in southern Indiana seems very promising, the status of the bobcat

north of Indianapolis is a big question mark. Perhaps a strategic and systematic camera-trap

survey could shed some light how the bobcat uses the fragmented agricultural landscape of

northern Indiana. One important strategic aspect of this study should logically concern the

current distribution of the bobcat in northern Indiana (i.e., as reported by Whitaker & Mumford,

2009), and how this information might be used to augment decisions concerning cam-trap

placement at a state-wide level. For instance, a comparative examination of a map of this simple


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distribution superimposed over a map of Indiana's major watersheds suggests that Lynx rufus

could be using the remnant gallery forests of these drainage basins to actively penetrate the

northern half of the state (See Appendix I, Maps 2 & 3). Therefore, placing camera-traps

strategically within an inferred range based on a combination of extant location data and

educated reasoning may allow for the most efficient use of limited resources. One important

systematic aspect of this bobcat camera-trap study would naturally concern the most effective

design of research methodology to properly suit the specific case of Lynx rufus. For instance, as

a crepuscular carnivore, Lynx rufus is shy and elusive, and most active after dusk, making it a

difficult species to observe in the wild. However, a study by Heilbrun et al. (2003) revealed that

bobcat individuals can be accurately identified on a consistent basis by the unique markings of

their pelage, and thus, capture-mark-recapture population studies can be effectively conducted by

camera-trap alone. Furthermore, the collective experience of researchers worldwide has shown

that the unique color and spot patterns of wild felids can be best recognized in full color images.

Therefore, a logical approach to photo-trapping the bobcat might consider a rotation of both

incandescent and infrared field cameras, thereby providing a supply of full color, nighttime

photographs for comparative purposes, while also limiting the spooking potential of incandescent

cameras alone.

Conclusion

The observation and documentation of wildlife distribution and movement patterns is of critical

importance as a source of baseline ecological information (Kays et al., 2011). Hence, it is not at

all surprising that the camera-trap, a device specifically designed to detect and document, has

become such an important tool in the world of conservation science. Many researchers have now

adopted the use of camera-trap technology as an Eulerian (location-specific) approach to meet

wildlife observation and population assessment objectives (Kays et al., 2011). Furthermore, a

plenitude of published literature suggests that camera-trap technology has been of exceptional

importance in the context of wild felid population monitoring initiatives. However, field camera

technology has yet to be utilized in the case of the Hoosier bobcat and the status of this cryptic

carnivore remains a mystery in the northern half of Indiana. Yet, perhaps a properly funded,


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state-wide cam-trap investigation of bobcat movement could yield the load of data necessary to

properly distinguish zones of bobcat residency from zones of bobcat transience.

Literature Cited

Abi-Said, M., & Amr, Z. S. (2012). Camera trapping in assessing diversity of mammals in Jabal

Moussa Biosphere Reserve, Lebanon. Vertebrate Zoology, 62(1), 145-152.

Aronsen, G. P. (2010). New photographic evidence of the African golden cat (Profelis aurata

Temminck) at Mainaro, Kibale National Park, Uganda. African Journal of Ecology,

48(2), 541-545.

Cheyne, S. M., & Macdonald, D. W. (2011). Wild felid diversity and activity patterns in

Sabangau peat-swamp forest, Indonesian Borneo. Oryx, 45(1), 119-124.

Dinets, V. (2003). First photo of a bay cat in the wild. Cat News, 38, 14.

Garrote, G., Gil-Sanchez, J. M., McCain, E. B., de Lillo, S., Telleria, J. L., & Simon, M. A.

(2012). The effect of attractant lures in camera trapping: a case study of population

estimates for the Iberian lynx (Lynx pardinus). European Journal of Wildlife Research,

1-4.

Gerber, B., Karpanty, S. M., Crawford, C., Kotschwar, M., & Randrianantenaina, J. (2010). An

assessment of carnivore relative abundance and density in the eastern rainforests of

Madagascar using remotely-triggered camera traps. Oryx, 44(02), 219-222.

Gil-Sanchez, J. M., Moral, M., Bueno, J., Rodriguez-Siles, J., Lillo, S., Perez, J., ... & Simon-

Mata, M. A. (2011). The use of camera trapping for estimating Iberian lynx (Lynx

pardinus) home ranges. European Journal of Wildlife Research, 57(6), 1203-1211.

Gutierrez-Gonzalez, C. E., Gomez-Ramirez, M. A., & Lopez-Gonzalez, C. A. (2012). Estimation

of the density of the Near Threatened jaguar Panthera onca in Sonora, Mexico, using

camera trapping and an open population model. Oryx, 46(03), 431-437.

Heilbrun, R. D., Silvy, N. J., Peterson, M. J., & Tewes, M. E. (2006). Estimating bobcat

abundance using automatically triggered cameras. Wildlife Society Bulletin, 34(1), 69-73.

Heilbrun, R. D., Silvy, N. J., Tewes, M. E., & Peterson, M. J. (2003). Using automatically

triggered cameras to individually identify bobcats. Wildlife Society Bulletin, 748-755.


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IUCN. (2012). The IUCN Red List of Threatened Species. Version 2012.2. Retrieved from

<www.iucnredlist.org>.

Kays, R., Tilak, S., Kranstauber, B., Jansen,P. A., Carbone, C., Rowcliffe, M., Fountain, T.,

Eggert, J., & He, Z. (2011). Camera traps as sensor networks for monitoring animal

communities. International Journal of Research and Reviews in Wireless Sensor

Networks (IJRRWSN), 1(2), 19-29.

Kelly, M., Caso, A. & Lopez-Gonzalez, C. (2008). Lynx rufus. In: IUCN. (2012). The IUCN Red

List of Threatened Species. Version 2012.2. Retrieved from http://www.iucnredlist.org.

Mohd. Azlan, J., & Lading, E. (2006). Camera trapping and conservation in Lambir Hills

National Park, Sarawak. The Raffles Bulletin of Zoology, 54(2), 469-475.

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Pureco Rivera, M. Q., & Leon Paniagua, L. (2012). Evidencias fotografica, biologica y

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Mexico. Revista Mexicana de Biodiversidad, 83(3), 825-833.

O'Connell, A. F., Nichols, J. D., & Karanth, K. U. (Eds.). (2010). Camera traps in animal

ecology: methods and analyses. Springer.

Reppucci, J., Gardner, B., & Lucherini, M. (2011). Estimating detection and density of the

Andean cat in the high Andes. Journal of Mammalogy, 92(1), 140-147.

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future?. Animal Conservation, 11(3), 185-186.

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University Press.

http://www.iucnredlist.org/


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Appendix I

Map 1: The 92 counties of Indiana.


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Map 2: Major Indiana Watersheds - The greater Wabash watershed includes the Wabash River (10) and eight

smaller tributaries: Raccoon Creek (16), Sugar Creek (15), Wildcat River (11), Deer Creek (12), Mississinewa River

(13), Salamonie River (14), Eel River (31), and Tippecanoe River (6) (Whitaker & Mumford, 2009).


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Map 3: Confirmed reports of Lynx rufus in Indiana from 1970-2001 (42 reports from 25 counties).


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Appendix II

Image 1: Incandescent field camera used by the author to take the following pictures

Image 2: Resident wildlife of Norton Lake, Indiana - Northern Raccoon (Procyon lotor)


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Image 3: Resident wildlife of Norton Lake, Indiana - Virginia opossum (Didelphis virginiana)

Image 4: Resident wildlife of Norton Lake Indiana - Raccoon and Opossum


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Image 5: Resident wildlife of Norton Lake Indiana - White-tailed Deer (Odocoileus virginianus)

camera-traps and bobcats - j.m. collins

Documents

device specifically

african golden

fragmented

wildlife society

iucn red list

automatically

infrared flash

norton lake