United States

Agriulture s Inexpensive Camera Systems for

Forest Service Detecting Martens, Fishers, and

Pacific Northwest f s

Research Station uiuther Animals: Guidelines for

General Techni cal

Report PNW-GTR-306 Use and Standardization

January 1993

'N Lawrence L.C. Jones and Martin G. Raphael

I +~~~~
Authors LAWRENCE L.C. JONES is a wildlife biologist and MARTIN G. RAPHAEL is a

research wildlife biologist, Forestry Sciences Laboratory, 3625 93d Ave. S.W.,

Olympia, WA 98512.
Abstract Jones, Lawrence L.C.; Raphael, Martin G. 1993. Inexpensive camera systems for

detecting martens, fishers, and other animals: guidelines for use and

standardization. Gen. Tech. Rep. PNW-GTR-306. Portland, OR: U.S. Department

of Agriculture, Forest Service, Pacific Northwest Research Station. 22 p.

Inexpensive camera systems have been successfully used to detect the occurrence

of martens, fishers, and other wildlife species. The use of cameras is becoming

widespread, and we give suggestions for standardizing techniques so that

comparisons of data can occur across the geographic range of the target species.

Details are given on equipment needs, setting up the stations, checking and

recording, summarizing data, and research needs.

Keywords: Camera, monitoring, marten, Martes americana, detecting,

standardization, fisher, Martes pennanti
Contents 1 Introduction

I Overview of the Technique

2 Bait and Lures

2 Construction of Camera Components

3 Mounting Stake

3 Camera

3 Trigger Mechanism

5 Preparation in the Field

8 Documenting Station Placement

8 Checking and Recording

8 Tally Sheet and Film Change

9 Film Processing and Recording

9 Census Nights

12 Thievery

12 Data Summaries

13 Storing or Moving Cameras

13 Research Needs

15 Request for Feedback on Information

15 Acknowledgments

15 References

17 Appendix 1

17 Materals

18 Appendix 2

18 Data Form

19 Appendix 3

19 Explanation of codes

20 Appendix 4

20 Monitoring Parameter Worksheet

21 Appendix 5

21 Example of a Detection Summary Table

22 Appendix 6

22 Example of a Target Species Worksheet
Introduction American martens (Martes americana) and fishers (M. pennant') are classified as

management indicator species of mature and old-growth forest conditions in most

National Forests of the Western United States. Abundance trends of these species

therefore must be monitored to meet the intent of the National Forest Management

Act and its regulations. These species are inherently difficult to monitor, though,

because of their secretive habits. Several techniques have been used to detect these

and other furbearers, including smoked aluminum track plates (Barrett 1983, Taylor

and Raphael 1988), hair snares (Jones and others 1991), and winter track counts

(Raphael, in press). Raphael (in press) compares the use of different techniques to

detect martens and fishers. Track plates work well but are bulky (Laymon and others

1991; Raphael, in press; Raphael and Rosenberg 1983). Positive identification of

tracks of similar mustelids (marten, fisher, and mink [Mustela vison]) often is difficult,

and the plates are not waterproof unless a cubby or waterproof roof is provided.

Winter track counts are effective only for determining the presence of martens and

fishers in areas of frequent snow with clearing periods and cold weather. Again, identification of similar mustelids is difficult. Hair snares are inefficient, at least with the

present technology (Jones and others 1991; Raphael, in press). The use of these

techniques may be insufficient to monitor martens and fishers, primarily because identification is tenuous and the techniques cannot be standardized across the geographic

range of the species.

Another recent development is the use of cameras. High-technology systems including a 35-mm camera, infrared sensor, recorder, and battery pack are effective but expensive, averaging over $400 (Mace and others 1990). Joslin (1977, 1988) demonstrates that inexpensive cameras (less than $20) also can be effective. We developed

an inexpensive camera system to detect martens and fishers.1 A pilot study in summer 1990 indicated that such a system can effectively detect martens and other carnivores (Jones and Raphael 1990). The results of the pilot study, a subsequent largescale study in western Washington, and a separate large-scale study in the southern

Sierra Nevada of California will be reported elsewhere (see footnote 1). The purposes

of this report are to provide users of these cameras with a summary of methods and

materials for surveying martens, fishers, and other wildlife and to provide suggestions

for standardizing camera survey protocols across the geographic range of these

species.

Overview of Simplicity is a primary benefit of inexpensive camera systems, but special attention

the Technique must be paid to some details to ensure proper functioning. Our camera system includes four major components (fig. 1): the mounting stake, camera, label stake, and

runner and bait. The camera is mounted on the top of the mounting stake, which is

set securely in the ground. A monofilament line runs from the trigger mechanism on

the camera, down the mounting stake, and out front through a runner (which keeps

the bait in place). Bait is tied to a washer on the other end of the runner with a single

strand of sewing thread. Behind and to the side of the bait is the label stake, which

displays information that will be shown in the photograph. The camera is waterproofed

with a plastic bag. When an animal comes to the station, it pulls on the bait, and a

photograph is taken (see color plates in center spread). The thread breaks after the

photograph is taken, so that the whole unit is not pulled down and dragged off.

'Raphael, Martin G. [and others]. Manuscript in preparation.

1
Camera

Label stake

, Mounting stake Runner and bait

Figure 1-Major components of camera system, side view.

Bait and Lures Martens and fishers have a naturally varied diet, including voles, squirrels, hares, birds, berries, insects, and carrion (Douglas and Strickland 1987, Strickland and

Douglas 1987). Thus, martens and fishers are somewhat opportunistic, and any of

several baits will work. In some studies (see footnote 1), chicken has been used for

bait because it attracts animals, is inexpensive, is readily obtained, and is easily secured to the thread. Raphael and others (see footnote 1) also tested the effectiveness

of raspberry jam and found that martens most often were detected at stations without

jam, although Laymon and others (1991) found that the use of jam with chicken and

a visual lure seems to increase the likelihood of fisher detections. Raphael and others

(see footnote 1) used decayed chicken (unrefrigerated for 2 days before placement at

a station) on occasion, in hopes of gathering early detections, but there was no indication that this was advantageous. Because chicken and other forms of protein provide a growth medium for bacteria that may pose a health problem to wildlife, domestic animals, and field crews, we recommend using fresh chicken. Wings and necks

are inexpensive and easy to tie or sew. Field crews handling chicken should use

latex gloves and wash their hands to avoid contamination.

The use of scents and other long-distance attractants is controversial, because martens and fishers may be drawn from outside the habitat or area being surveyed. If the

objective of a study is merely to see if any animals are nearby, use of lures may be

warranted, however. It is unknown how well lures work, let alone from what distance

a lure will draw the target species. The use of lures needs further investigation.

Construction of Before cameras can be set up in the field, some components must be prepared in the

Camera laboratory. We recommend cameras requiring 110 film because they are inexpensive Components and the quality of prints is adequate. Cameras without a built-in flash can be left in- Components definitely without the risk of battery failure (batteries will die within a few days in

2
cameras having a built-in flash). The connection with an external flash may be problematic, however; often the flash is not triggered (see footnote 1). One solution is to

wire two D-cells to a camera with a built-in flash, thereby extending the life of the batteries for about 3 months. 2 Total cost of materials for one complete 110 camera set

is $15-25, depending on choice of camera and other materials.

Construct the components as follows (the order is unimportant).

Mounting Stake An angle iron is made from a 15- by 3.5-centimeter strip of perforated metal strapping, bent midway at a 904 angle. The top (horizontal surface) of the angle iron

serves as the platform, where the camera will be attached (fig. 2). Glue the hook part

of hook-and-loop tape onto the upper surface of the platform. If this does not provide

for a secure mounting, a wider platform can be attached to the strapping, or the

camera can be attached with wire, rubber bands, or duct tape.

Secure the vertical side of the angle iron to the upper part of the mounting stake. Drill

an 8-millimeter hole through the mounting stake, 3.5 centimeters from the top. Put a

washer on a bolt and push the, bolt through the perforation of the angle iron and the

hole in the stake. Secure the angle iron with a washer and wing nut on the opposite

side of the stake.

Put an eye screw one-third to one-half of the way down the stake on the same side

as the trigger mechanism. Size of the eyescrew does not matter, except that a large

one is unnecessary.

Camera Press a heated eye screw (4 millimeters inside diameter) into a location on the plastic

camera body that will not interfere with the operation of the camera but will allow free

movement of the trigger mechanism (fig. 3). Heat the eye screw with a Bunsen burner

until it is just red hot. If the screw is not hot enough, it will not penetrate well; if it is

too hot, it will melt the surrounding plastic in the camera, and the screw will fall out.

Glue the loop part of the hook-and-loop tape onto the lower side of camera; this will

fit onto the hook part glued to the platform. Make certain that the loop material does

not interfere with the winding mechanism of the camera.

Label the camera with a unique number (engraving works well).

Trigger Mechanism Coat hanger wire is used to make the trigger mechanism, loop, and runner (fig. 4).

Cut the hanger as shown in figure 4A. The hanger portion is not used, so one and a

half coat hangers are needed to make the three components.

To make the trigger mechanism, first construct a prototype from one-half of a coat

hanger. Bend the wire into a shape that will rotate freely in the eye screw(s) or strap

holder and will trip the shutter release when downward pressure is applied. The

distance from the shutter release to where the apex bends down needs to be 13

centimeters to ensure a consistent shutter tripping pressure. Place the prototype on a

5- by 10- by 30-centimeter board and hammer in heavy nails at the points where the

wire bends (fig. 4B). Cut the heads off the nails. The board and nails then can be

used as a template to mass produce trigger mechanisms. Each mechanism must be

tested on a camera to ensure that unwinding off the template did not alter its shape.

2personal communication. 1992. Richard Golighty,

Department of Wildlife, Humboldt State University,

Arcata, CA 95521.

3
Hook and loop

Wing nut Binder clip Thumbtack

'w. f i/Angle iron

V g 0 Camera Station

number n number

Washer- Xt 28

Bolt / JLy- A Month

Bolt Year

Index cards 7 Day

o - Eye screw

Garden stake

Figure 2-Mounting stake (left) and label stakes (right).

Flash bar

Trigger mechanism

Shutter Eye screw

release C/

numberY L /Angle iron

Viewfinder Len platform

Hook and loop Monofilament C

Angle iron+|9 I

1t tv gym ~Wing put

Figure 3-~Components of camera Mounting stake Bl

at top of mounting stake. The loop Washer

and plastic waterproofing bag are

not shown.

4
To make the loop, take another one-half of a coat hanger and widen it into a U-shape

(fig. 4C). It must be wide enough to keep the plastic bag from obstructing the lens,

or at least 8 centimeters. The loop can now be attached to the mounting stake at

the front of the camera with duct tape.

The runner is used to secure the bait in the camera's field of view. Wrap the last

one-half of a coat hanger around a nail to make a small loop at the apex of the coat

hanger (fig. 4D). In soft ground, one-half of a coat hanger length should be sufficient;

in hard ground, a shorter length (one-third of a coat hanger) may suffice.

Preparation in One person can set up the camera in the field, but it is easiest if two people do it;

the Field one person sets up the mounting stake and camera, while the other works on the

runner, bait, and label stake. If one person is doing the entire setup, she or he

should position the mounting stake and camera first to avoid getting the odor of the

bait on the camera and mounting stake. Otherwise, animals may be attracted to the

scent on the camera and cause damage or misalignment. The person preparing the

mounting stake and camera uses the following steps:

1. Clear the area of brush and'other debris to ensure an unobstructed view for the

camera and that debris will not inhibit the functioning of the system.

2. Hammer the mounting stake securely into the ground so that the camera lens will

be pointing toward the bait.

3. Put the trigger mechanism on the camera. The free ends are fed into the eye

screws or strap holder, or both, depending on the camera.

4. Securely mount the camera on the mounting stake with the hook-and-loop tape.

Make sure the winding mechanism is free of the platform.

5. Tie the monofilament onto the apex of the trigger mechanism. Feed this through

the eye screw on the mounting stake and out 2.5 meters to the runner. Feed the

monofilament through the runner and tie it to the washer on the other side.

6. Squeeze the free ends of the runner and push it into the ground (compression

holds it in). Allow 2 centimeters of play in the monofilament.

7. Put film in the camera and advance it to exposure 1. This is done after the camera

is attached to prevent accidental shots.

8. Insert the flash bar, if used. Make sure the flash bar clicks into place, or it will not

make contact with the flash mechanism of the camera. If external batteries are

used, they should be in a waterproof container (for example, a margarine tub)

secured to the mounting stake or another nearby stake.

9. Place the plastic bag over the camera and flash. Cut out the area in front of lens,

inside the loop. Use clear tape to fasten the plastic bag to the loop (fig. 5).

10. Use a thumb tack to attach the bottom of the bag to the mounting stake, below

the loop, allowing the trigger mechanism and monofilament to remain movable.

The following is a list of steps the second person takes:

1. Securely sew a single strand of thread to the bait (or do this in the lab). Sew

around a bone if possible. Alternative options for attaching bait are discussed in

"Research Needs."

2. Tie the other end of the thread to the washer, leaving no more than 3 centimeters

between the bait and the washer.

5
B.

C. D.

Figure 4-Coat hanger is cut in half (A) to make the trigger mechanism

(B), loop (C), and runner (D). The coat hanger is bent around headless

nails on a template to make trigger mechanisms in quantity (B).
Figure 6-A plastic bag protects the camera from rain. The area in

front of the lens is cut away and the bag is taped to the loop.

3. Put thumbtacks through the binder clips on the label stake. The binder clips are

used to hold the label cards and allow easy removal and replacement.

4. Cards for labels should be some color other than white to reduce glare, with date,

camera number, and station number in bold, black letters, at least 35 millimeters

high. Use only indelible ink. Make sure the labels will be legible on the photograph

and that they do not obstruct the view when the camera is triggered by an animal.

The label stake should be about 1 meter behind the bait and off to the side about

0.5 meter. Be sure the label cards will not be so high as to be out of the upper

range of the camera.

5. When the camera is set up, the horizontal and vertical aims need to be checked,

as these can be substantial sources of error (Laymon and others 1991; see footnote 1). Do not do this by looking through the viewfinder. An easy and effective

way to check the vertical aim is to look back at the camera from the bait. If the top

of the camera is visible, it is pointed too far down; if the bottom of the platform is

visible, the camera is pointed too far up. To check the horizontal aim, look down at

the camera and monofilament line to see if the longitudinal axis of the camera is

perpendicular to the monofilament line. Laymon and others (1991) suggest using a

3-meter section of monofilament line to determine both horizontal and vertical

axes, with the bait being lined up at their coincidence. The vertical aim can be

adjusted at the camera by swinging the platform up or down, and the horizontal

aim is adjusted by moving the runner to one side or the other.

7
6. Always do an initial test shot to make sure the camera, flash, and setup are functioning properly. For the test shot, pull on the washer and do not block the view of

the label stake. Be sure to advance the film to the next exposure number. When

advancing the film, make sure the trigger mechanism is off the trigger, and that

the film is being advanced as far as possible. Do test shots randomly after the

camera is up and running to ensure its continued functioning.

Documenting Stations should be mapped on orthophotographic quadrangles. The Universal TransStation Placement verse Mercator coordinates need to be recorded (this can be done after-the-fact with

Geographic Information Systems [GIS]). Data on the position also should be recorded

(for example, left or right side of road in direction of checking; near large log, snag,

or stream; distance to the road; distance to an edge). Various amounts of data should

be collected on vegetative and other parameters in the stand where the station is

placed, but this depends on the objectives of the study. A great deal of habitat use

information is attainable if the sample of first detections is adequate. The GIS overlays can aid in this respect, but it depends on the quality of the GIS data available.

Checking and Every time the camera is visited, change the date and check to see if the camera can

Recording be wound; if it can, an exposure has been made. Also check the flash to see if it

needs to be flipped or replaced. Check to see if the bait needs to be replaced or

retied to the washer. Glance at the entire camera system to see if it is looks functional; a variety of problems can arise after the initial set up, such as monofilament

breaking or being chewed off, monofilament or thread wrapped around the runner,

runner coming out of the ground, platform being tilted up or down, and bag obscuring

the lens.

Record the following information at each camera station whenever it is checked: station number, camera number, date, nights run, bait type, bait condition, and comments (see appendices 2 and 3). The exposure number should be recorded only if an

exposure has been made. These data are essential and should be used for standardization, although additional information may be recorded if the study objectives require

such.

Tally Sheet and To keep track of the number of exposures taken on each roll of film, it is important to

Film Change keep a daily tally sheet. The sheet should include the camera numbers in columns

and station numbers in rows. When an exposure is taken, a tick mark is put in the appropriate box. When the desired number of exposures has been made, the film can

be pulled, and the date noted on the tally sheet. The desired number of photographs

depends on the resources and desires of the crew. In general, it is a good idea to pull

film early on, after only two or three exposures, to ensure correct functioning and aim

of the cameras. For example, some people may have a tendency to point the camera

too high, whereas others point it too low, or the label stake may be consistently out

of the view. After an initial check of this sort, the film can be left in until all 12 exposures have been made. A word of caution, however: film left in a camera that is destroyed by a bear or stolen is lost data. It therefore is a good practice to pull film prematurely in areas of high risk from destruction by wildlife or thievery or when target

species are suspected (such as when scats are found where the bait was-a common occurrence with martens).

8
Film Processing Before pulling film from a camera for processing, it should be advanced to the end to

and Recording prevent light leaks. The camera number, station number, and roll number or date

need to be recorded immediately on the film cartridge. When the film is taken in for

processing, the same information should be written on the envelope and receipt. This

is important, because label cards may be obscured by large animals or may otherwise

be out of the photograph. The data on the envelope, along with the exposure number

on the data form and photograph negative, are useful in determining when and where

every photograph was taken.

After the film is developed, the back of each photograph should be labeled with the

species identification (four-letter code of scientific name for mammals, reptiles, and

amphibians; four-letter code of common name for birds), date (as shown on label

stake, because a time lag occurs between the actual exposure and checking), station

number, and camera number. After the photograph is labeled, the four-letter code of

the species is entered on the data sheet. Some species may be difficult to distinguish

from one another (such as species of chipmunks), and they can be given a code with

the first two letters of the genvs, followed by "SP" (for species). If an animal is in the

photograph but cannot be positively identified, it should be entered as "UNKN." If exposures are indicated on the data sheet but lack a species code or "UNKN," it indicates that either the camera was stolen (or film otherwise ruined) or some other problem occurred. For exposures on stolen or ruined film (for example, from a bear

ripping open the camera and exposing the film), the code is "STOL" or "RUIN," respectively. All other exposures taken are given the code "NPIC," for no picture. The

NPICs can occur for various reasons, such as the flash not firing, incorrect vertical or

horizontal aim, runner pulled out of the ground, excessive glare, half or double exposures, shaky mounting, or simply nothing visible in the photograph (see footnote 1).

By itemizing the NPICs, it is possible to determine the major sources of error and, if

human error, which persons in particular are having difficulty.

Census Nights Census nights (CNs) are analogous to trap nights and are determined by the number

of nights run (NR), nonfunctional cameras (NFUN; analogous to sprung traps), and

the visit frequency (VF). One NR equals one 24-hour period, starting from the time

the camera is set up. If the camera is nonfunctional, the species code block on the

data form should have "NFUN" entered while in the field. The camera is considered

functional if an exposure is taken. Examples of NFUN include having the thread

wrapped around the runner or chewed through by insects, or the trigger mechanism

hung up on the plastic bag. The VF is the number of NRs between checks of the

cameras. The number of CNs run during a transect is most accurate if the cameras

are checked daily (VF = 1), but this is not always feasible or necessary. In addition,

daily checking may compromise the amount of surveying that can be done. Regardless of the VF (below the threshold level, see below), the NR will remain the same,

To determine the number of CNs, use the following formula, where NR equals cameras used times number of nights run:

CN= NR NFUN* VF 2

9


Example: 12 cameras are run for ten 24-hour periods; they are checked every other

day; on three visits, a camera is not functioning:

CN= 120 - 3 = 117.

A threshold level of 20 percent visitation rate (by all species of animals to cameras)

per check should be established. If more than 20 percent of the cameras are registering exposures with a particular VF, then they should be checked more often (a

minimum of daily). The threshold level is established to minimize the number of potential photographs lost when an animal visits a station that has already registered an

exposure. This should allow for better comparisons between areas of a lesser and

greater visitation rate. We recommend a VF of 2 (every other day), unless the threshold level is surpassed.

Thievery Humans, being curious by nature, have a tendency to investigate any unknown structure. And some of them feel that a camera in the forest is certainly lost, so it is appropriate to take it home. Therefore, it is necessary to take precautions to keep cameras

from being stolen. The best way to do this is to hide them, or at least make them inconspicuous. We have found that using fluorescent flagging to mark camera locations

off roads is a bad idea, so we switched to using white with blue dots. This resulted in

a marked decrease in camera thefts, and this type of flagging did not conflict with

other color schemes in the forest. Still, it is best to check with the land managers to

see if a certain flagging color is acceptable. In areas with a high level of human

activity, the station can be offset from the flagging by a consistent distance and

azimuth (for example, 40 meters from flagging, southeast when east of a road or

southwest when west of a road). In addition, small tags inscribed with text explaining

the purpose of the camera may be helpful.

Data Summaries The simplest summary of a camera survey should include three tables. A monitoring

parameter table (appendix 4) should include basic information about the study design:

number of transects, number of stations per transect, total number of stations, census

period, number of NFUN, CN (do not include NFUN), VF, pattern, spacing between

stations, habitat selectivity, bait type used, use of lures, and any other information that

may have a bearing on the results or determine interarea bias.

A detection rate summary (appendix 5) is used to calculate relative abundances. The

parameter table should reflect consistencies to effectively demonstrate relative abundances. Relative abundance comparisons are based on detection rates and not on

individual animals, because one animal may visit more than one station and several

animals may visit a single station. The detection summary should include a list of species (avoid lumping nontarget species into broad categories, such as "squirrels"),

number of photographs per species, detection rates for each species, number of stations with detections, and station detection rates (number of stations with detections

divided by total number of stations). This should be done for each area (or transect if

monitoring is not extensive). These figures should be subtotaled, with UNKN, NPIC,

STOL, and RUIN entered into the total.

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A target species worksheet (appendix 6) includes specific information on the detections of those species of concern, with some inferences about the number of animals

that may be in the area. The information summarized should include the total number

of target species photographs (TSPs), the number of stations with TSPs, the number

of the night run (NR) when each photograph was taken, the NR and station number

of first detections, the distance to the nearest station that also had a TSP, number of

nearest station with a TSP, and suspected number of individuals of each target species. A word of caution: the number of individuals is a best guess and probably has a

low degree of precision. The best guess is based on spatial and temporal detections.

An estimate must reflect information gathered on natural history (particularly home

range size and age classes of target species present at a given time). The estimate

of individuals present may be important as a tool to identify areas where target species have a low density vs. high density but may never be statistically powerful.

Optional summaries and analyses may include habitat use information gathered from

either the field or GIS, or both. Data gathered from the field are useful for determining

microhabitat parameters, such as tree species composition, canopy closure, stem

basal area, snag or coarse woody debris density, nearness to streams (can be done

on GIS if overlays exist, but GIS may not cover ephemeral streams), vertical canopy

hierarchy, ground cover, and an assortment of other parameters. Again, clearly outline your objectives so you can develop a sound data form. Information from GIS has

less resolution than field data, and generally is applicable to landscape level variables, such as stand age class of each station and surrounding stands, elevational

and aspect parameters, perennial riparian usage, and distribution of stations with or

without detections in relation to one another.

Storing or The camera sets can be kept intact during moving or storage by carefully winding the

Moving Cameras monofilament around the mounting stake. Use duct tape to keep the monofilament

from forming a "bird's nest' and to keep the runner in place. If the cameras and

flashes are left on the stake, they often will fire in transit, so we recommend

removing them.

Research Needs Using inexpensive cameras to document occurrence or monitor population trends is a

new and little-tested technique. Additional research is needed to improve the camera

system design, determine optimal surveying schemes, and determine how well the

cameras detect target species, especially when compared to other techniques.

Several suggestions have been made onimprovements to the basic design. Some of

these include:

Using wire rather than monofilament for the trip line.

Using polyvinyl chloride (PVC) pipe to cover the monofilament.

Using a plastic tent stake with a hole drilled near the top as a runner.

Putting bait in a cheesecloth bag to protect it from insects.

Using surgical thread to tie bait.

Using an alligator clip to attach bait to monofilament.

Putting a cover over the bait to protect it from ravens, bears, and other common

nontarget species.

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Using a U-shaped piece of metal strapping as the mounting stake in areas of

loose soil.

Housing the camera in a plywood box for use in snowy areas (Bull and others, in

press).

Attaching the camera directly to a tree to minimize shaky photography.

Whatever modifications are made to the camera system, they should not cause the

camera to function differently. For example, using a trigger mechanism made from an

L-shaped piece of metal and tightened by a nut and bolt may present problems. The

tightness of the bolt may differ from camera to camera, which causes a differential

trigger pressure and introduces a source of bias.

Temporal and spatial influences on detection success need investigating. The time it

takes to get a desired proportion of first detections is not well known and may differ

among geographic areas and target species. Raphael and others (see footnote 1)

noted that first detections of martens at different stations averaged about day 8 in

their 1990 survey, and they got first detections up to 29 days after the cameras had

been set up. On one transect that they ran for more than 8 days in their 1991 survey,

they found that most first detections occurred after day 8. It was not known how many

individuals were being photographed, or which of the photographs were repeats of

martens already photographed at other stations. A relation probably exists between

the spacing of the stations and detection success, but it currently is not known. There

also is the possibility that the target species will be leery of camera stations early on

and may not visit the stations until they get comfortable with their presence. Optimal

spacing and length of running time need to be researched in different areas for different target species. Radio telemetry alone is not sufficient to do this, because several individuals of the target species may be present in the area being surveyed.

Individuals must be marked in a manner allowing for their recognition in a photograph.

This means that as many individuals as possible (preferably all of them) must be livetrapped, marked, and released before the camera survey period, which is a timeconsuming endeavor. Suggestions for marking include hair shaving, freeze-branding,

and attaching colored collars or ear tags. Ear tags may be a problem with animals

that have thin ear tissue and the animal must be posed in just the right position to

determine its identity. Until further research is done, we recommend running cameras

for 3 weeks. We recommend a spacing regime allowing four cameras inside the home

range (the average home range of the sex with the smaller average) of the target

species. Use a home range size based on a study done in the same geographic area

if possible, or in the most similar habitat. Home ranges rarely are circular, but if four

cameras are placed within a radius of a home range, it is hoped that at least one will

fall within the true home range.

Cameras are most easily checked along roads or trails, but the influence a road has

on the behavior of an animal is unknown. Also, roads tend to follow topographic

features such as riparian areas or ridgetops or areas of timber harvest or development. Target species may find some of these features preferable, whereas other features may be avoided. Research needs to be done in roaded areas (experimental

transects) concomitantly with areas away from roads (control transects) to determine

inherent biases associated with road surveys. The best study would include control

and experimental areas in the same stand.

14
The best time of year to survey depends on the geographic area, natural history of

the target species, objectives of the study, and logistics. Cameras are easiest to run

during the late spring through early fall when snow is absent, but detections are probably most difficult to get in the summer, when prey and other food items are in abundance. Because most animals give birth in the spring or summer, nonresident animals

may be present during this time. Transects run during the spring before inclusion of

young will not be comparable to transects run after young have started foraging in

the summer.

Other techniques for monitoring target species exist, and some may be quite effective.

More research is needed to determine how well cameras detect target species when

compared to other techniques. Cameras have mostly been used to detect martens,

fishers, and other forest carnivores. Track plates also have been used successfully.

These two techniques in particular need further comparisons in several areas to

weigh the costs and benefits of each technique.

Request for The authors would like to receive feedback on how well this system works for others;

Feedback on include data summaries, as described above, and any helpful suggestions. By comInformation piling information from various locations, we can make better recommendations on

the use and efficiency of cameras for detecting occurrence or monitoring. The address is given on the inside front cover.

Acknowledgments We thank Paul Joslin for demonstrating this simple and cost-effective technique to us.

Jim Swingle, Gus Bekker, Warren Michaelis, and Deborah Ferber monitored cameras

in the field and supplied valuable input on improvements and troubleshooting. Teresa

Ritter, Mary Rasmussen, Diane MacFarlane, Mike Knowles, and crews of the Sequoia

and Stanislaus National Forests contributed summaries of their camera monitoring

efforts and many helpful suggestions. Many others have contributed to our knowledge

of monitoring with cameras, and we thank them all. We thank Janet Jones for her

editorial assistance. The manuscript benefitted from review by William Zielinski and

Steve Laymon.

References Barrett, Reginald H. 1983. Smoked aluminum track plots for determining forbearer

distribution and relative abundance. California Fish and Game. 69(3): 188-190.

Bull, Evelyn L.; Holthausen, Richard S.; Bright, Larry. [In press]. Comparison of

three techniques to monitor marten. Wildlife Society Bulletin.

Douglas, Carman W.; Strickland, Marjorie A. 1987. Fisher. In: Novak, M.; Baker,

J.A.; Obbard, M.E.; Malloch, B., eds. Wild furbearer management and conservation

in North America. Toronto: Ontario Ministry of Natural Resources: 511-529.

Jones, Lawrence L.C.; Raphael, Martin G. 1990. Ecology of marten in the Pacific

Northwest. 44 p. Progress report. On file with: Pacific Northwest Research Station,

Forestry Sciences Laboratory, 3625 93d Ave., SW, Olympia, WA 98512.

Jones, Lawrence L.C.; Ruggiero, L.F.; Swingle, J.K. 1991. Ecology of marten in

the Pacific Northwest: technique evaluation [Abstract]. In: Ruggiero, L.F;; Aubry,

K.B.; Carey, A.B.; Huff, M.H., tech. coords. Wildlife and vegetation of unmanaged

Douglas-fir forests. Gen. Tech. Rep. PNW-GTR-285. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 532.

Joslin, Paul. 1977. Night stalking: setting a camera 'trapline' for nocturnal carnivores.

Photo Life. 7: 34-35.

15
Joslin, Paul. 1988. A phototrapline for cold temperatures. In: Freeman, H., ed.

Proceedings of the fifth international snow leopard symposium; 1986 October;

Srinagar, India. Bombay, India: Conway Printers Private Ltd.: 121-128.

Laymon, Steven A.; Overtree, Lynn; Collins, Gary; Williams, Pamela L. 1991.

Final report on the distribution of marten, fisher, and other carnivores in the

Starvation, Tyler Creek, and Capiro Creek and White River drainages of the

Sequoia National Forest: summer 1991. 13 p. Report. On file with: Kern River

Research Center, P.O. Box 990, Weldon, CA 93283.

Mace, Richard; Manley, Tim; Aune, Keith. 1990. Use of systematically deployed

remote cameras to monitor grizzly bears. 25 p. Report. On file with: Montana

Department of Fish, Wildlife, and Parks, Box 67, Kalispell, MT 59901.

Raphael, Martin G. [In press]. Techniques for monitoring fishers and American

martens. In: Buskirk, S.W.; Harestad; A.S.; Raphael, M.G: Powell, R.A., eds.

Biology and management of martens and fishers [Location of publisher unknown]:

Cornell University Press.

Raphael, Martin G.; Rosenberg, Kenneth V. 1983. An integrated approach to wildlife inventories in forested habitats. In: Bell, J.F.; Atterbury, T., eds. Renewable

resource inventories for monitoring changes and trends: Proceedings of an international symposium; 1983 August 15-19; Corvallis, OR. SAF 83-14. Corvallis, OR:

College of Forestry, Oregon State University: 219-222.

Strickland, Marjorie A.; Douglas, Carman W. 1987. Marten. In: Novak, M.; Baker,

J.A.; Obbard, M.E.; Malloch, B., eds. Wild furbearer management and conservation in North America. Toronto: Ontario Ministry of Natural Resources: 531-546.

Taylor, Cathy A.; Raphael, Martin G. 1988. Identification of mammal tracks from

sooted track stations in the Pacific Northwest. California Fish and Game.

74(1): 4-11.

16
Appendix 1 Materials needed for camera sets are as follows:

Camera: 110 type that will take flash bar and has no battery. Alternatively, a 110

Materials with built-in flash with two D-cells wired to camera battery connections.

Film: 12 exposure. We have found that 100 ISO works well; 200 ISO is rather

grainy.

Flash: whatever type fits the camera.

35- by 35- by 600+-millimeter garden stake for mounting camera.

35- by 20- by 600+-millimeter garden stake for label cards.

Label cards: 76- by 127-millimeter nonwhite cards to label station number,

camera number, and date. We typically use one card with the month, one with

the day (reusable), and one with the station and camera number.

Thumbtacks: for anchoring plastic bag and binder clips.

Binder clips: small ones attached to label stake with thumbtacks to hold label

cards.

Plastic bag: 1-gallon freezer bag (not sealing type) with the part over and in front

of the lens cut away.

*Clear tape: to attach freezer bag to loop of coat hanger.

Duct tape: to attach loop of coat hanger to mounting stake and securing the

system while moving or storing.

Glue: to glue hook-and-loop tape. Airplane glue or similar works well.

Strapping: perforated metal strapping 35 millimeters wide and 150 millimeters

long for the angle iron and platform. The perforations should be 9 millimeters in

diameter.

Bolt and wingnut: to attach platform to stake; 8-millimeter size.

Hook-and-loop tape: to attach camera to platform.

Coat hangers: for (1) triggering mechanism, (2) runner, and (3) loop over lens to

support waterproofing bag. Use templates to make these in quantity.

Eye screw: one or two small ones in camera, attached by heating them and

sinking into camera body. Another eye screw is put in the stake to guide the

monofilament.

Monofilament: 1 0-kilogram test; strung from triggering mechanism to washer.

Washers: one attached to monofilament and bait thread just past runner and

another for the bolt and wingnut; 9-millimeter size.

Thread: normal gauge sewing thread to tie to bait and washer.

Bait: chicken wing or other small piece of chicken (back, neck).

Tools needed:

Tool box or tacklebox to carry items.

Hatchet or hammer.

. Scissors.

Pliers (lineman and needle-nose).

Waterproof marker.

. Flagging.

Extras of everything listed under "Materials."

All normal field gear and data sheets.

17
Appendix 2 OBS c-kS WEATHER 3 TEMP _____TRANSECT NUMBER___ P I OF 3

LOCALITY OL'YMPIC. egNiItStLAL- HO4MPTULIe5 DOtAIY"AnE

Data Form GENERAL COMMENTS M1ANY HUN-rI6RS AROUwND

STN CAM EXP NIGHTS BAIT

NUM NUM NUM SPECIES DATE RUN BAIT COND. COMMENTS

Pall ILC z/o/ 7 t I 

P.20oa oil NFAN 2- 3 z ct.e

Pao3 Ole, IB 0

Ploq 0 i &l r1AAM z S -

P206 I>? 3 CAFA _ _3 0 rc!

P:ZO(, o01 3 MAAM 3 6. (b0 PIC!

P.o7 1 33 -

PZo8 I 37 _ 2

PF2(9 I o_ 1. 0

P21zo 001 H NPIC _ 3 ScT-APIPL|

Pll1 I39 3 MAPS _ _ _ __ 3

P2aa Oil - 0O _ _ _ _ (~~~~~~A.' sro tsN1 P113 O;A Li STOL i- 3 S H/o/cqja

Paiq1 059 - 0 

P115 6H 11 T _ . r

Pa14 I147 NFUN 9 8 _ z -1M4a

PI17 io: - 2. 0 

P21 8 -i Li G1R 5A _AZIPNZ' I 2 

p~i9 Iq0 I12 LARAIA2 3

P2a o o06 7 NPIC 3fume?, "l 

PaM 062 - / O

P22 It 3 $PE6, _ , _ 2 <skun k'

P243 oI3 I P _ 2. o 

18
Appendix 3 Code sheet and explanations of codes for Camera Monitoring Data Form

Explanation of Codes (appendix 2).

HeaderOBS: Observer's initials.

WEATHER:

1 = dry 7 = moderate snow

2 = fog/mist 8 = heavy snow

3 = light rain/drizzle 9 = mixed rain/snow

4 = moderate rain 10 = freezing rain

5 = heavy rain 11 = hail

6 = snow drizzle/light snow 12 = other (explain)

TEMP: Temperature in Celsius.

TRANSECT NUMBER: Chronological.

P OF : Page number of total pages-if more than one person runs the

transect, then total pages are combined.

LOCALITY: General locality of transect.

GENERAL COMMENTS: Anything that concerns overall pattern of checking stations.

Data entrySTN NUM: Station number, chronological; may use abbreviations of locality (for

example, "N" for North Cascades) and transect number. Example: N323 = North

Cascades, third transect, 23d station of this transect.

CAM NUM: Number inscribed on camera.

EXP NUM: Exposure number-recorded onlywhen the shutter has been tripped by

an animal (does not include test shots, accidental firings).

SPECIES: Four-letter code for species is entered or one of the following: NPIC =

nothing in photo or exposure problem; UNKN = animal in photo, but unidentifiable;

STOL = film from stolen camera; RUIN = film ruined by animal, falling tree, etc.;

NFUN = nonfunctional camera (NFUN entered in field-no exposure number can

accompany it).

DATE: Use European method of entering dates; for example, 10 Oct 1992.

NIGHTS RUN: Number of nights elapsed since set-up day.

BAIT: Type of bait used: 1 = chicken; 2 = chicken/jam; add additional codes as

needed.

BAIT COND: Condition of bait when checking the camera: 0 = untouched; 1 =

gnawed (by anything from martens to ants), not replaced; 2 = gnawed, replaced; 3 =

bait gone; 4 = thread chewed off; 5 = untouched, replaced (for example, when

chicken is dried out).

COMMENTS: Anything to help decipher photos in lab, such as accidental firings,

scats found, target species seen in area, malfunctioning camera or flash, stolen

camera info, and so forth.

19
Appendix 4 The following is a monitoring parameter worksheet. It is filled out for each general

area monitored (for example, a Ranger District, drainage, mountain range, and so

Monitoring Parameter forth, depending on the extent of monitoring).

Worksheet

Recorder

Affiliation and address

Contact phone (and DG, if applicable)

Location of study area (area reporting on)

Census period

Number of transects

Transects per station

Total stations

Number of NFUN

CNs (subtract NFUN)

Checking frequency

Pattern (grid, irregular, road transect, etc.)

Spacing (distance between stations)

Habitat selectivity (old growth only, towards streams, random, etc.)

Bait used

Lures used (include olfactory, auditory, visual)

Observations and recommendations

Other comments

20
Appendix 5 Example of a simple detection summary table. Assume 1,000 CNs and 40 stations.

Note that the subtotal and total will usually not be the summation of items listed

Example of a Detection above for, stations with detections or station detection rates, because more than

Summary Table one species may be detected per station.

Species and Number Stations Station

other photo of Detection having detection

designations photos ratea detections . rateb

Marten 4 0.40 4 0.10

Common raven 39 3.90 22 .55

W. spotted skunk 21 2.10 10 .25

Ermine 17 1.70 5 .13

Baird's tapir 1 10 1 .03

Subtotal 82 8.20 31 .78

Unknown 2 .20 2 .05

STOL 21 2.10 2 .05

NPIC 77 7.70 40 1.00

Total 182 18.20 40 1.00

a Detection rates are photographs per 100 CNs.

b Station detection rates are the number of stations with detections per number of

stations monitored.

21
Appendix 6 Target Species MARTeN

Recorder Sr. K. 5W1s6LE

Example of Target Affiliation and Address PWVJ RESGARCH SrATION' 3v2,S q3CAvr S'M

Species Worksheet ly.e'a. WA BaSoZ - LAS Fores4- Seruvce.

Contact Phone (and DG, if applicable) (2oG) 956- 23-iS Do- SZ4LO9A

Study Area Location OL'IMPIC PeNIN SLXLA

Number of Target Species Photographs (TSPs)_ _ _

Number of Stations with TSPs I

Suspected Number of Individuals 3

Station Detection Rate (number of stations with TSPs divided by total

number of stations monitored) -/45 Ol.vo

STATION NUMBER

2.01 20q Z05 206 Z.11 7zq Z3 2

DATE FIRST DETECTION 23/o8 zI/o3 z/o ZZ/6a O 17/0?

NIGHTS RUN FIRST DETECTION 8 7 G 7 5 3 3

NIGHTS RUN NEXT DETECTIONS Iz 2 7 8 _=

8 Ii

____ _-.

NEAREST STATION WITH 209/

DETECTION 2c4 205 20G 205 20o 23Z. Zz9

DISTANCE TO NEAREST STATION I 0.5 0 0.5 .5 Z.5 1.5 1.5

WITH DETECTION I' km km I _ km km 1CM

COMMENTS Sv spev* m osrcn * 201- a l J Z+-3IL; l-oIceC. 4OUA-OC- 9

t4r eApcCY cA 41;s SC irnc 1cMr.

22
Jones, Lawrence L.C.; Raphael, Martin G. 1993. Inexpensive camera systems for

detecting martens, fishers, and other animals: guidelines for use and standardization.

Gen. Tech. Rep. PNW-GTR-306. Portland, OR: U.S. Department of Agriculture, Forest

Service, Pacific Northwest Research Station. 22 p.

Inexpensive camera systems have been successfully used to detect the occurrence of

martens, fishers, and other wildlife species. The use of cameras is becoming widespread,

and we give suggestions for standardizing techniques so that comparisons of data can

occur across the geographic range of the target species. Details are given on equipment

needs, setting up the stations, checking and recording, summarizing data, and research

needs.

Keywords: Camera, monitoring, marten, Marnes americana, detecting, standardization,

fisher, Martespennanti.

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Agriculture is dedicated to the principle of multiple

use management of the Nation's forest resources

for sustained yields of wood, water, forage, wildlife,

and recreation. Through forestry research,

cooperation with the States and private forest

owners, and management of the National Forests

and National Grasslands, it strives-as directed by

Congress-to provide increasingly greater service

to a growing Nation.

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programs will be given equal consideration without

regard to age, race, color, sex, religion, or national

origin.

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Portland, Oregon 97208-3890

* U. G.P.O.: 1993-791.582
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P.O. Box 3890

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