THE C120 MAGNUM WITH PAN TRIGGER: A HUMANE TRAP FOR MINK (MUSTELA VISON) Author(s): Gilbert Proulx, Morley W. Barrett, and Stephen R. Cook Source: Journal of Wildlife Diseases, 26(4):511-517. Published By: Wildlife Disease Association DOI: http://dx.doi.org/10.7589/0090-3558-26.4.511 URL: http://www.bioone.org/doi/full/10.7589/0090-3558-26.4.511

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Journal

THE

C120

MAGNUM

WITH

TRAP

FOR

Gilbert Proulx,12 1 Humane Trapping

Morley Program,

W. Barrett, and Stephen Alberta Environmental Centre,

Present

Diseases. © Wildlife

26(4), 1990, pp. 511-517 Disease Association 1990

PAN TRIGGER:

A HUMANE

Vegreville, 2 Present P.O. Box

of Wildlife

MINK

(MUSTELA

VISOM

R. Cook13 Bag 4000,

Alberta, Canada TOB 4L0 address: Forestry Department, Alberta Research Council, 8330, Postal Station F, Edmonton, Alberta, Canada T6H 5X2

address:

Fiberglass

Canada,

P.O. Box 595, Edmonton,

Alberta,

Canada

T5J 2L1

The C120 Niagnum trap, equipped with a 66 x 69 mm pan trigger, which favored strikes in the neck and thorax regions, successfully killed nine of nine wild mink (Mustela in simulated natural conditions. Average times to loss of consciousness and heartbeat were estimated at 79% of all captured mink unconscious in s3 mm (P < 0.05). This is the first mink kill trap to meet the requisites of the Canadian General Standards Board regarding killing traps. Key words: C120 Magnum quick-kill trap, humane trapping, mink, Mustela vison, rotatingjaw trap, experimental study. ABSTRACT:

double vison)

quine trap

INTRODUCTION

Because ciated wildlife

of

the

perceived

with use of management

the

cruelty

leghold authorities

Canadian provinces have ited the use of conventional in land sets for capturing (Barrett et al., 1988). commercially available

asso-

turer)

tnap, the of three

dian General Standards Board’s (1984) threshold values (minimum striking clamping

recently prohibleghold traps most furbearers

trap

Corporation, Lititz, USA) has been promeans for trapping The Conibean 120

(Canadian Trappers Alberta Vocational

However, the with a two-prong tently

strike

standard trigger, mink

al., 1973; clamping recommended

Voigt, energies

Standards

Board

americana)

in

vital

(Cook

and

mink

for

marten

(Cook

et

Magnum

et al. (1989a) trap

(the

developed researchers

the did

et

stronger

the 1989a)

bones

work with demonstrated

This in

al.,

of

the

marten that

respectively,

unconsciousness. the central nervous

ac511

produced

peded imals

the respiratory (Proulx et al.,

strike could

locations, have the

double regions

C120 not

(Pnoulx

ing-jaws,

develop Magnum

Pnoulx,

1989). Pnoulx

mink.

struck

and rapid damaged

mink. The

(Martes

and

and

the

1989a),

mink. (Proulx double

strikes, where animals were simultaneously struck in the head-neck and thorax regions by the distal and proximal notat-

1974) and its impact and are lower than those by the Canadian General (1984)

and

However, et al.,

equipped not consis-

areas

marten marten

region

culature

Federation, Centre, 1987).

C120, does

for killed

kill and

but did not effectively kill mink struck in the neck (Proulx and Barrett 1989). This may be due to the greaten cervical mus-

(C120) is marketed as a quick-kill trap for mink (Mustela vison) and its use is recommended in trapping and conservation manuals 1984;

forces)

quickly

head-neck

In most regions, the rotating-jaw Coni-

bears (Woodstream Pennsylvania 17543, moted as an alternative small furbearens.

a registered trademark so that the can be produced by any manufacwhich rated higher than the Cana-

a trigger trap that

strikes on im-

functions of the an1989a). Given similar

the C120 potential

objectives

consistent Double system

of this system

will

Magnum to quickly study

were for

ensure

trap kill (1)

the C120 consistent

strikes in the head-neck and thorax of mink, under simulated natural

to

512

JOURNAL

OF WILDLIFE

DISEASES,

VOL.

26, NO.

1990

4, OCTOBER

were individually introduced in 5.2 x 4.4 m test enclosures and were a minimum of 3 days to acclimate to simulated natural conditions before any tests were conducted. Enclosures were kept under surveillance with two remote control Panasonic#{174} WV 1854 video-cameras (Avicom Industrial Communications, Edmonton, Alberta, Canada T5S 1G7) equipped with a Comiscar#{174} 15-180 mm F1.9 lens (Avicom Industrial Communications, Edmonton, Alberta, Canada, T5S 1G7) and a high efficiency 500 watt infrared (invisible to animal eyes) light illuminator (Avicom Industrial Communications). Personnel observed the video monitors in a laboratory building approximately 125 m from the enclosures. Proulx et al. (1989b) described the facilities, equipment and husbandry procedures. The C120 Magnum traps used in this study were similar to those of Proulx et al. (1989a). However, they had four clamping bars instead of two to reinforce the trap’s metal frames (Fig. 1). Traps were set in a ground cubby box (Fig. 2) (Proulx et al., 1989b) similar to the one used by trappers (Alberta Vocational Centre, 1987). caught

mink

12.2 x allowed

FIGURE

trap

with

1. Diagram four clamping

conditions; tial of the mink which

of the Conibear bars.

120 Magnum

and (2) to evaluate C120 Magnum to received a double MATERIAL

the potenquickly kill strike.

AND METHODS

The study was conducted in a 2.2 ha forested compound at the Alberta Environmental Centre (Vegreville, Alberta, Canada TOB 4L0). Wild-

0

4

8

cm FIGURE

2.

C120

Magnum

with

66

x

69

mm

pan

trigger

in cubby

set.

PROULX

They

were

operated

equipped on

a

with

pan

movement

confirmation

at

firing

a trigger

on

video of

time.

TRAP

FOR

MINK

513

which

triggers

principle (Fig. 3). A of ranch mink feed was tied down the center of the trap.

tests

(Proulx

et

monitors the

These

by

striking

tests

projecting

bars

were

system that would would be consistently struck and thorax regions. A trigger

on

used

the the

TRAP

JAWS

LEVER

al.,

1989a, b). In order to qualify for each category of testing, traps had to pass the previous category. In approach tests, naive animals that presumably had never encountered a Conibear trap8 were allowed to approach C120 Magnum traps wired in the set position so that the traps could be triggered but not close completely and injure the animals. The strike locations were determined

HUMANE

cam-lever

bait consisting 10 cm behind A test sequence was designed to minimize pain and suffering of animals, to ensure efficient use of mink, and to thoroughly evaluate the killing potential of traps. It consisted of approach tests, pre-selection tests, kill tests, and performance

ET AL.-A

arc

animals

to develop

ensure

that mink in both head-neck system was judged

acceptable if animals were successfully positioned in five or more of six approaches. Two series of six approaches were conducted with a 65 x 100 mm and a 81 x 91 mm pan triggers. However, during the approach tests, it was noticed that mink could accidentally fire the trap before entering it, by stepping on the anterior part of the part of the pan which faced the cubby entrance. The pan was subsequently shortened to a 69 mm length so that it did not extend past the proximal striking jaw (Fig. 2). In the past, a trap was judged “humane” when it rendered three of three animals irreversibly unconscious within 3 mm (Federal Provincial Committee for Humane Trapping, 1981). However, Proulx et al. (1989a, b) considered that a sample size of three was unacceptably low to reach a satisfactory conclusion about the true effectiveness of a trap. They suggested that the assessment of the killing ability of a trap should involve more kill tests and that a trap should be considered “humane” if it has the potential to kill >79% of all target animals in an actual field situation. Such a performance level is considered to be very high and no commercial trapping device has been shown to meet it (Proulx and Barrett, 1989). This study followed previous kill test protocols (Proulx et al., 1989a, b). The killing potential of the C120 Magnum trap was first assessed in pre-selection tests with six traps and six mink (those used in the approach tests with the 65 x 100 mm pan trigger) immobilized with ketamine hydrochloride (10-20 mg/kg; Austin Laboratories, Joliette, Quebec, Canada J6E 3Z1).

AM

FIGURE

3.

Diagram

ger of the Conibear

of the

66

120 Magnum

x 69 mm trap.

This preliminary assessment allowed searchers to determine if the C120

generated fering

not

sufficient

effectively

unlikely that

impact

that are

aware

kill

what

do so with is

the reMagnum

clamping

en-

causing sufdevice would

immobilized

it would of

and

mink, without If a trapping

to quickly kill to the animals.

ergies

pan trig-

animals,

active

happening

it

is

animals to

them

and would “fight” the trap (Proulx et al., 1989b). The C120 Magnum would pass the pre-selection tests if it rendered at least five of six animals irreversibly unconscious in 3 mm (Canadian General Standards Board, 1984). Irreversible unconsciousness was diagnosed by loss of corneal and palpebral reflexes (Walker, 1979; Horton, 1980; Rowsell et al., 1981) with inevitable subsidence into death (loss of cardiac activity determined with a stethoscope). The immobilized animals were situated in traps in a position that duplicated placement in the approach tests (Proulx et al., 1989b), and the presence of their eye reflexes was confirmed before firing the trap. Upon success at the pre-selection test level, a second assessment of the potential effectiveness of the C120 Magnum was carried out in six kill tests with each trap equipped with a 66 x 69 mm pan trigger and placed in a cubby set. The C120 Magnum would be considered potentially effective if it successfully rendered at least five of six animals irreversibly unconscious in 3 mm. Thereafter, the C120 Magnum was evaluated in additional kill tests, termed performance confirmation tests, in order to be 95% confident that it could be expected to effectively kill >79% of all captured mink (Proulx et al., 1989a). On the basis of the normal approximation to the binomial distribution (Fleiss, 1981), the C120 Magnum would be expected to effectively kill >79% of mink on traplines if, during the kill and performance confirmation tests, it rendered nine of

514

JOURNAL

TABLE reflexes

OF WILDLIFE

DISEASES,

26. NO. 4, OCTOBER

VOL

of strikes, time intervals and major trauma of

1. Location and heartbeat,

between trap firing mink in preselection after

Loss

Mink number

Weight (kg)

87-975

Location Sex

1.0

F

(

and

1990

firing

and

irreversible

tests

with

M

1.4

Top

of

of double strikes

and

Magnum

trap.

(sec)

reflexes

Heartbeat

137

324

T/’ sktill

C120

Corneal/ palpebral

Major Severe

T

5

180

trauma

and

Compression

muscles 87-998

loss of corneal/palpebral

the

at

impact

Dorsal

compression

of temporal

Severe

meningeal

hemorrhage.

ventral

compression

Lungs

of

laceration

sites.

severely

of

muscle. Dorso-

muscle

congested

at

and

T.

edema-

tous. 87-991

0.8

F

Top

of

skull

5

T4

and

152

Transverse

fissure

at impact (2

site

cm

brain.

laceration

87-992

1.7

F

of skull

Top

and T,

140

187

of

Lungs

bone

hemorrhage

dorsal

surface

of

compression

muscles spinal

and

Dorso-ventral with bone

on Severe

of

fracture gested

discrete

diameter)

frontal

of frontal

(1 cm)

and

at

T

process.

and and

small

Lungs

con-

edematous. compression deformation

congested

and

of the skull but no fracture. possibly

edema-

tous.

87-1011

1.5

87-995

1.1

cervical thoracic

SI: male,

and

T

Muzzle

and

48

compression

of muscles

Lungs

at

and

congested

impact

slightly

279

Compression at

C5 and C.

and

slightly

and laceration Lungs markedly edematous.

of

muscles

congested

vertebrae U: unkown

or

of

13

failures)

(two

14

mink

(one

failure),

irreversibly

or 18 uncon-

in

3

mm

(Proulx

et

al.,

mentation.

RESULTS

All strikes

Mild sites.

edematous.

,,

C

1989a). The kill tests were conducted from October 1987 to February 1988. Upon firing of the trap, researchers ran to the test enclosure to monitor the state of consciousness of the animals. Animals were necropsied by a veterinary pathologist at the Alberta Environmental Centre (Vegreville, Alberta, Canada TOB 4L0). The pelts were examined for damage before and after skinning the animals. Animal husbandry and research procedures were conducted in accordance with the guidelines of the Canadian Council on Animal Care (1984). Protocols for the kill tests were referred to the Council for their review prior to implescious

226

26

vertebrae

F: female,

20

C

U

(0 failure),

nine of

M

approach tests in the head-neck

resulted in double and thorax regions.

In pre-selection of consciousness (±63) sec and (Table system pression

tests,

average

times

and heartbeat 225 (±66) sec,

to loss

were respectively

60

1). Damage to the central nervous was apparent in two cases. Comand/or laceration of muscles and

congestion of lungs were common in all kills (Table 1). The trap successfully passed (six of six) the pre-selection tests. All the kill and performance confirmation tests majority reflexes the

were (78%) had

observers

successful of cases,

been and

lost

(Table 2). corneal/palpebral prior

to

average

time

arrival to

consciousness was 79% of captured mink unconscious in s3 mm (P < 0.05).

trauma

vertebrae

animal

and nal

F

64’

T1 and

-

Major

67

T

and

Heartbeat

vertebrae

thoracic

M:

0.8

reflexes

and T,,1’

Joint

87-962

palpebral

DISCUSSION

The

C120

Magnum

with

pan

trigger

the first mink kill trap to meet the requisites of the Canadian General Standards Board (1984). Because of its longer springs, the C120 Magnum is easier to set than the C120. It is a safe trap the springs are equipped identical to those of the

to work with when with safety hooks Conibean 220 trap

is

516

JOURNAL

OF WILDLIFE

(Woodstream

DISEASES,

and

Corporation)

Conibear

Safety

Corporation) gether while

VOL. 26. NO. 4, OCTOBER

Gripper5

when tothe

al. (1989a, to increase However,

b), illustrates the killing it also points

should

exercised

be

statements past, double mainly

devices. Proulx

of

et

that it is possible potential of traps. out that caution

in expressing

general

about types of strikes. In the strikes were not acceptable

because

such

strikes

had

critically evaluated. nary work on double

Some strikes

of the prelimiinvolved only

a few

inconsistent

animals

and

never

been

strike

cations (Novak, 1981) or trap designs were much less powerful than the Magnum (Gilbert, 1981). Research animals

in simulated

natural

is necessary to confirm of trap whose energies kill thresholds nadian General These ment

cation and time the accumulation essary mances

the killing potential meet or exceed the by Board

lead to the between

to unconsciousness, of background

to interpret of traps on

which C120 using

environments

recommended Standards

animal studies of relationships

lo-

the working

the Ca(1984). establishstrike lodata

and nec-

killing perfortnaplines.

ACKNOWLEDGMENTS C. Dulberg and A. W. Hawley for statistical advice; B. Dew, D. Hobson, D. Nelson and J. Nolan for technical help; A. Lopez for postmortem examinations; and E. Rudik and M. We

thank

Schultz

for machine

ALBERTA

VOCATIONAL

shop

LITERATURE and

CENTRE.

work.

CITED 1987.

Trapping

5th ed. Alberta Advanced Education and Alberta Forest, Lands and Wildlife, Lac La Biche, Alberta, Canada, 524 pp. BARRETT, M. W., C. PROULX, AND N. JOTHAM. 1988. Wild fur industry under challenge-The Canaconservation

manual,

North

Resources

CANADIAN

the jaws Although

to that of commercial study, and the work

response.

Natural

C120 Magnum is more powerful than the C120 (Proulx et al., 1989a), it did not damage mink pelts. The efficacy of this trap under controlled conditions now warrants field studies to compare its capture efficiency This

dian

a

(Woodstneam

is used to hold setting the trap.

1990

American

Wildlife

COUNCIL

ON

ANIMAL

1984.

CARE.

to the care and use of experimental 2. Ottawa,

Ontario,

GENERAL

CANADIAN

and

53: 180-190.

Conference

Canada,

208

STANDARDS

Guide

animals,

BOARD.

1984.

humane mechanically-powered, ger activated. Report CAN 2-144.1-M84, imal

traps,

wa,

Ontario,

CANADIAN

Canada,

TRAPPERS

an trappers da, 231 pp. CooK,

L.,

M.

tario

manual.

North

1984.

Bay,

Canadi-

Ontario,

L. WALKER. furbearer animal

AND

of some

Ministry

of

An-

trigOtta-

9 pp.

FEDERATION.

NOVAK,

fectiveness

Vol.

pp.

Natural

Cana-

1973.

Ef-

traps.

On-

Resources,

Toronto,

Ontario, Canada, 39 pp. CooK, S. R. , AND C. PROULX. 1989. Mechanical evaluation and optimization of the rotating-jaw Conibear 120 trap. ASTM Journal of Testing and Evaluation 17: 190-195. FEDERAL

PROVINCIAL

TRAPPING.

1981.

COMMITTEE

FOR

Final

Committee

report

the Federal Provincial Wildlife nadian Wildlife Service, Ottawa, ada, FLEISS,

J.

172 L.

pp. 1981.

proportions, York,

New

Conference, Ontario,

Statistical

methods

2nd ed. John

Wiley

York,

321

HUMANE

for

of CaCan-

rates

and

and Sons, New

pp.

the humane potential of traps-The Vital and the Conibear 120. In Proceedings of the Worldwide Furbearer Conference, J. A. Chapman and D. Pursley (eds.). Worldwide Furbearer Conference Inc., University of Maryland, Frostburg, Maryland, pp. 16301646. HORTON, J. M. 1980. Use of anaesthesia, care of the unconscious. British Medical Journal 281: 3840. NOVAK, M. 1981. Capture tests with underwater

GILBERT,

snares,

F.

F.

1981.

leg-hold,

Maximizing

Conibear

and

Mohawk

traps.

Canadian Trapper 9: 18-23. PROULX, G., AND M. W. BARRETT. 1989. On the development and implications of the Conibear 120 Magnum trap to harvest marten and mink. In Proceedings Northeast Fur Resources Technical Committee, R. Lafond (ed). Beauport, Quebec, Canada, pp. 194-209. AND S. R. CooK. 1989a. The C120 Magnum trap: An effective quick-kill trap for marten. Wildlife Society Bulletin 17: 294-298. S. R. CooK, AND M. W. BARRETT. 1989b Assessment and preliminary development of the rotating-jaw Conibear 120 trap to effectively kill marten (Martes americana). Canadian Journal of Zoology 67: 1074-1079. R0wSELL, H. C., J. RITCEY, AND F. Cox. 1981. Assessment of effectiveness of trapping methods in the production of a humane death. In Proceedings

of the

A. Chapman

Worldwide and

Furbearer D.

Pursley

Conference, (eds.).

Worldwide

J.

PROULX

Furbearer

land, VOICT.,

Conference

Frostburg,

D.

1974.

American WALKER,

Trap

Trapper A. E.

Inc.,

Maryland,

1979.

testing 3:

University

pp.

of

Mary-

1630-1646.

and

22: Received

in

of cerebral

HUMANE

death.

TRAP FOR MINK

Advances

167-172.

development.

14-17.

Advances

tion

ET AL-A

the

determina-

for

publication

26

May

1989.

in Neurology

517