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Non-Target Animals Trapped. Report from Dr. Donald A. Molde on great number and variety of animals "incidentally" trapped in Nevada.
Contact info@trailsfe.org for more data. 

 

February 20, 2014

Dave McNinch, Chairman
Trapping Committee
Nevada Board of Wildlife Commissioners
1100 Valley Road
Reno, Nevada  89512

Regarding:  Non-target trapping deaths and injuries

Dear Chairman McNinch

On behalf of TrailSafe, this letter provides information to your committee regarding non-target deaths and injuries caused by Nevada trappers which directly bears on the issue of trap visitation, and perhaps on needed modifications to trapping practices as well.  Surely, this deserves a place on the agenda at some point before final decisions are made by your committee.

 None of this information was seen by the legislature during its deliberations regarding SB 213.  Had it been part of the discussion, we believe many members would have found it of interest and pertinent to their deliberations. 

First up is the data compiled by NDOW from trapper self-reports for the time period noted. You have seen these numbers before but the committee has never discussed them.

Non-Target Summary Data Reported to NDOW by 20% or Fewer Trappers
Years 2002-2004, 2007, 2010-2013

Animals

Species

Number

Released Unharmed

Released Injured

Dead

Rabbits

4190

191

400

3145

Dogs

195

163

14

16

Cats

116

33

7

28

Mountain Lions

172

135

8

17

Other

183

15

5

153

Livestock

25

15

3

5

Game

33

20

3

4

Badger

1

0

0

1

Bear

2

2

0

0

Bobcat

1

1

0

0

Chipmunk

5

0

0

6

Ermine

1

0

0

1

Feral Pig

1

0

0

0

Ground Squirrel

11

1

1

9

Pack Rat

193

0

0

191

Pond Turtle

5

5

0

0

Skunk

4

1

0

3

Total

5138

582

441

3579

Birds

Golden Eagle

9

9

0

0

Hawks

11

10

0

1

Owl

1

1

0

0

Blue Heron

1

0

0

1

Chukar

4

0

0

4

Coot

17

2

0

15

Ducks

50

9

7

21

Geese

5

2

2

1

Magpie

97

2

5

89

Quail

3

0

0

3

Rail

1

0

0

1

Raven

35

6

4

22

Total

234

41

18

158

Totals

Species

Numbers

Uninjured

Injured

Dead

Animals

5138

582

441

3579

Birds

234

41

18

158

Total

5372

623

459

3737

 

Next up is new information not yet seen by your committee.  In reviewing NDOW’s lion carcass check-in spreadsheets from 2008 – mid-2013, comments were noted by NDOW biologists and other staff regarding injuries observed during routine inspection of the carcass.  Although staff was apparently not specifically looking for evidence of trap injuries, observers found the following.  Of 986 dead lions checked in during this period, these injuries were noted (each lion counted only once):

Mountain Lion Injuries from Check in Data:  2008 – 2013

Missing toes

43

Foot injuries consistent with trap capture

44

Broken/missing canine/incisor teeth

41

Total

128/986 = (13%)

 

While true that we cannot be certain that all injuries noted above came from contact with traps, it seems likely that some, if not most, did.  Winston Vickers, DVM, MPVM, UC Davis Wildlife Health Center, told us this about his experience examining lions in California: 

That is correct that we have never seen a missing toe or apparent foot or leg injuries here (maybe a past toe dislocation or two) – but nothing else in 145 live captures and a large number of necropsies of animals hit by cars or taken on depredation permits or for public safety

A major difference between Nevada and California regarding day-to-day risks for injury to lions is the absence of leg hold traps in California.  Other risk factors for injury….struggling with prey species and the like… should be about the same.  Therefore, Nevada lions appear to be injured at a 1:7/1:8 ratio most likely due to traps.

Cold Weather Foot/Other Injuries Due To Traps

Recently, Wild Felid listserv, a discussion group where academics, researchers and biologists compare notes about large and small cat issues in the Western Hemisphere, had a discussion about thermal injuries to bobcats: The discussion was prompted by a researcher who posed the following question: 

We are trapping bobcats with MB550s with offset jaws to radiocollar them.  Our trapping protocol calls for traps to be closed if wind chill dips to -10F or below.  I think that is too low, however, we did not have problems during the first 2 years.  This year, on the other hand, we had a bobcat's paw freeze below the point of capture when the ambient low was 16F above.  We warmed the paw and our vet thought it would be okay.  Nonetheless, I do not want that to happen again.  Can anyone recommend a safe protocol?  Any help would be appreciated.

Winston Vickers, DMV, MPVM of UC Davis Wildlife Health Center was one of several who responded.  (A portion of his lengthy comments is presented here.  His entire email response is attached,[can be requested from info@trailsafe.org]

Bold/italics are ours:

Hello Suzie,
Thanks for posing this question because it brings up issues not only with temperature but also as Ivonne says of time in the trap.
Both issues, appropriate temps for trapping and frequency of checks deserve a lot more discussion than has occurred to date in the wildlife research community in my view
Of course on the issue of ambient temps, one is assuming that at either high or low temps animals in the environment have coping mechanisms to handle them. However, when confined the animal may not be able to use some mechanisms such as seeking the coolest shade or water for high temps, or warmer den environments in cold temps.  In either case, since we researchers often are not place trapping devices in the most ideal location for avoiding extremes (ie a shady spot or sheltered spot chosen for a trap might still not be the “best” location the animal would choose to mitigate temp extremes), it is incumbent upon us to not allow the animal to be in confinement long enough for temperatures to be damaging.  So time-in-trap becomes the first area that we can minimize through protocols and technology.
As to effects of the trap or snare itself on the tissues distal to the gripping point and likelihood of damage at a particular temp, the medical literature and research on tourniquets is the best guide for expectations of injury related to foot hold traps (since no one has to date that I know of done any detailed comparisons of biochemical parameters, nerve conduction, or nerve / muscle fiber condition, and pain that compare trapped limb versus matching limb in field trapped animals).  However, typical foot hold traps and snares often produce some level of complete or partial restriction of blood flow to the limb distal to the mechanism and / or damage at some level to the tissues at the gripping pointAdding extreme hypothermic conditions would presumably make the situation worse
Going back to the tourniquet-like effect of many foot hold and snare trappings - the net of the research suggests that after 2 hours of full or partial (which is sometimes even more damaging) blood flow restriction, pain (sometimes significant) is present from the get-go and emanates from nerve fibers both distal and proximal to the gripping point, and damage to tissues begins to occur distal to the gripping point or at the gripping point that can result in long term loss of neuromuscular function or persistent pain.  Damage also occurs with release of the restriction (reperfusion syndrome) that can be local or in worst cases systemic, potentially leading to organ damage or even death.  After 2-4 hours in many experimental models damage and chronic pain can be significant and permanent.
I have attached several review publications and a collection of abstracts relating mostly to the experimental research on tourniquets which is normally conducted in rats, rabbits, cats, and dogs – with the latter two having the most direct potential for comparison.  The net of all of it in my view as a veterinarian and wildlife researcher is that the axiom of “first do no harm” should be uppermost in any trapping activities – recognizing that even a short period of any confinement generates stress “harm” that researchers have the greatest obligation (of all people who deal with wildlife) to minimize, and that leg holds have the most potential of all of our techniques.  When one moves from something like cage traps (least potential physical harm) to foot holds and snares, it becomes incumbent on the researchers to use every means possible to not cause damage to the animal.  Too often I think in the past, wildlife researchers have assumed that if an animal did not die post trapping that techniques were probably fine.  The ability to detect less than lethal negative effects has been minimal, or those effects have not been looked for (“see no evil” syndrome). 

To my mind this very extensive research into the effects of vascular restriction suggests there is no excuse for not monitoring foot hold traps / snares either continually or at a minimum every 2 hours once set.  and tendencies to bite at traps and damage teeth
I am just urging clear–eyed assessment of the likely realities for the animals, versus hopeful but perhaps unrealistic views of the effects of our capture choices.
Winston Vickers
T. Winston Vickers, DVM, MPVM
Associate Veterinarian, Wildlife Health Center, UC Davis
Co-PI and field lead – Southern California Cougar Project
Hazing group coordinator, Oiled Wildlife Care Network
949-929-8643

twvickers@ucdavis.edu, winstonvickers@charter.net
www.wildlifehealthcenter.org
Staff Veterinarian, Institute for Wildlife Studies
vickers@iws.org
www.iws.org


More on Frostbite

In response to a question from us about trapper claims that bobcats cannot suffer frostbite in traps in below freezing weather, Dr. Vickers said this:


Hello Don – I agree that trappers are full of hooey if they say an animal can’t suffer hypothermic damage to tissues, especially tissues that are deprived of circulation in a foothold, though as I mentioned in my email some research suggests “cooling” the tissues (not freezing them) reduces the damage from circulatory impairment a little.
Winston

There is evidence of probable frostbite injury to ears and tails of lions.  For example, the entry of 5/17/13 on the 2013 NDOW lion check in data spreadsheet, reads as follows:
 
Part of ear missing as well as several inches at tip of tail.

Other examples of ear and tail injury can be found throughout the spreadsheets, suggesting that frostbite has to be strongly considered as a likely cause for these findings.

Why would Nevada lions suffer frostbite injuries to ears and tails?  One possibility is that lions caught in traps and unable to move around can suffer frostbite to ears and tails by virtue of confinement in the trap.  If ears and tails can freeze, it’s clear that foot injuries due to freezing conditions can also occur.

This data also supports the possibility that one of the ways lions in Nevada escape accidental trapping is by suffering frostbite to foot parts, leading to sloughing of dead tissue…e.g. toes/pads….and release from the trap.

Conclusion

It’s clear that the 96-hour trap visitation interval is woefully out of date, trapper claims that there are no problems with current trapping practices are strongly contradicted, and the carnage inflicted upon Nevada’s non-target wildlife and domestic animals demands modification of trap visitation intervals, and perhaps modification of trapping practices as well.   

The capture, injury and death of thousands of non-target species, including hundreds of dogs, cats and mountain lions and many thousands of rabbits is incomprehensible to the non-hunting, non-trapping public.

It cannot be claimed that trapper convenience “trumps” what we have shown here, that this carnage is acceptable “collateral damage” for a virtual handful of Nevada trappers to pursue a dangerous activity, especially on public lands. There is no way the non-hunting, non-trapping public will accept that position.

Therefore, trap visitation must undergo significant revision to improve chances for non-target animals and birds to be released from traps with as few injuries as possible, including injuries that occur due to delay in being released from traps.

Trapping practices need to minimize capture of rabbits, pack rats, mountain lions, birds of prey and all the rest.  Snares should be removed as a legal means of killing wildlife.  Non-target animals and birds have little to no chance of release from snares.  Snares are not necessary, and provide nothing but convenience for trappers at the expense of unacceptable carnage to wildlife. 

Multiple traps/snares deployed at a single trap site should be banned.  Once a rabbit/pack rat/other animal is caught by one device, the area becomes a de facto baited trap site with the trapper claiming no responsibility.  Eagles/hawks/owls are accidentally caught in this manner.

Quotas must be considered since much of this destruction is driven by rising pelt prices, leading to more trapper effort, and therefore more danger to non-target wildlife and domestic pets alike.

Trappers should be directed away from areas where accidental lion capture is more likely.  

NDOW must DEMAND data from trappers about non-target capture as a condition for licensure. Non-compliance by trappers should be met with non-renewal of their trapping licenses.  The non-hunting, non-trapping public is entitled to know this information and we will be asking for it.

 

In short, fur trapping in Nevada is out of control and needs to be fixed.  Significant trapping reform is long overdue.

For your convenience, and for the convenience of your committee members, we have attached the NDOW trapper self-report data, NDOW lion check in data spreadsheets, Dr. Vickers’ WildFelid complete email response, and Dr. Vicker’s tourniquet studies

Sincerely

Donald A. Molde