Transcript Item 32A Kimmer Trapping Ban Implications (FGC 4-14

Legal and
Ecological Implications of the
Bobcat Trapping Ban:
Impacts Upon Numerous State and Federally
Listed Threatened and Endangered Species
Introduction
 Bobcats fulfill a valuable role in the
ecosystem.
 But bobcats significantly influence
numerous species of fauna.
 Consideration of a trapping ban did
not consider ripple effects upon
other species – especially
threatened, endangered and
special status species of concern.
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Fish and Game Commission
Decision-Making
 Commission Mandate
 “State Law requires the Commission
to consider credible science over
opinions or conjecture. Fish and
Game Code Sec. 703.3 states, ‘It is
the policy of the state that the
department and commission use
ecosystem-based management
informed by credible science in all
resource management decisions to
the extent feasible.’ ”
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CA Endangered Species Act
Mandates Upon The FGC
2055. The Legislature further finds and declares that it is the policy of this state that
all state agencies, boards, and commissions shall seek to conserve endangered
species and threatened species and shall utilize their authority in furtherance of the
purposes of this chapter.
2053. The Legislature further finds and declares that it is the policy of the state that
state agencies should not approve projects as proposed which would jeopardize the
continued existence of any endangered species or threatened species . . . . . if there
are reasonable and prudent alternatives available consistent with conserving the
species . . . which would prevent jeopardy.
2061. "Conserve," "conserving," and "conservation" mean to use, and the use of, all
methods and procedures which are necessary to bring any endangered species or
threatened species to the point at which the measures provided pursuant to this
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chapter are no longer necessary.
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Species of Concern
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Pacific Fisher
Ecological Implications
 Predation is the largest cause of fisher mortality,
and bobcats are the # 1 source of fisher predation.1,2
 70-90% of fisher mortality
is from predation.
1
 60% killed by bobcats
…twice as many as by all
other predators.
2, 3

1. CDFW, Fisher Status Review Report, May 12, 2015

2. Wengert, G. Trends in Fisher Predation in California. 2011

3. Spencer, W., et al. Southern Sierra Nevada fisher conservation
assessment. 2015
Bobcat leaving fisher den hole in tree
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Pacific Fisher
Ecological Implications, cont’d
 Bobcats prey predominantly on
female fishers.
 “Mostly female fishers killed by
bobcats.”
1, 2
 “Killing females results in death of
2-4 kits.”
3
Bobcat, dead female fisher
1. Wengert, G. Trends in Fisher Predation in California. 2011.
2. Wengert, G. Ecology of intraguild predation on fishers (Martes pennanti)
in California. 2013.
3. Sweitzer, R. and Barrett, R. SNAMP Fisher Study: Sources of Mortality. 2009
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Humboldt Marten
Ecological Implications
 Bobcats are the # 1 predator of martens.
1
 “44% of marten predation due to bobcats” in
one study.
2
 “All 9 marten mortalities from bobcats” in
second study.
3
 Bobcats killed mostly females with young.
4
 “Predation of martens, primarily by
bobcats…..[the] limiting factor for marten
population distribution and persistence.”
5
Bobcat photographed in marten den tree
1.
2.
3.
4.
5.
CDFW Report to FGC - Evaluation of Petition to List the Humboldt Marten as Endangered Under CESA, October 13, 2015, citing Stone, 2010.
USFWS, 2015
USFWS, 2015
Slauson et al. (2009b)
Slauson et al., 2014; Bailey, Oregon State University, 2014.
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San Joaquin Kit Fox
Ecological Implications
 Predators are # 1 cause of death for SJ kit fox.
 SJ kit fox deaths “78% killed by predators”.
2
 “Bobcat predation on SJ kit foxes” # 2 cause.
 “12 kit fox skulls in one active bobcat den.”
1.
2.
3.
4.
1
3
4
Benedict, Forbes, 1973
Berry, Harris 1987
Standley, Berry, O’Farrell, Kato 1992
Benedict, Forbes 1973
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Kangaroo Rats
Ecological Implications
6 T&E Listed Species
Fresno Kangaroo Rat
 Table 1 - Bobcat Diet 1
 Food Items - Occurrence
 Mammals
100%
 Rabbits
60.0%
 Kangaroo Rats
20.0%*
 Woodrats
10.0%
(Dipodomys nitratoides exilis)
Giant Kangaroo Rat
(Dipodomys ingens)
Morro Bay Kangaroo Rat
(Dipodomys heermanni morroensis)
Stephens' Kangaroo Rat
(Dipodomys stephensi)
Tipton Kangaroo Rat
(Dipodomys nitratoides nitratoides)
San Bernardino Merriam's Kangaroo Rat
(Dipodomys merriami parvus)
 Grasshopper Mice 05.0%
 Pocket Mice
05.0%
 Birds
Tr.0%
___________________________________________________________
Bobcat with kangaroo rat
**K-Rats #2 Most Common Prey**

1. Ellis, Schemnitz, 1958
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Desert Tortoise
Ecological Implications
 “Carnivores,
especially coyotes
and bobcats prey on
tortoises.”
1
 Even “Large
tortoises may be
eaten by . . .
bobcats.”
2


1. San Diego Zoo, 2012
2. San Diego Zoo, 1982-2012
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Endangered CA Bighorn Sheep
Ecological Implications
Threat to Several Races of
CA Bighorn Sheep
 CDFW Helicopter Photos
Threat to Young and
Female Bighorn Sheep
Bobcat Kills CA Bighorn Ewe
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“Bobcats threaten Sierra Nevada bighorn sheep survival.” – USDA, APHIS 2000
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Greater Sage Grouse
Ecological Implications
“...documented sage-grouse
predators [i.e., bobcats…]”
Predator-Attacked
Sage Grouse?
– ZB Lockyear, et al. 2013
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How many more special status species
which are highly-susceptible to bobcat
predation, must be put at risk?
Burrowing owl
Least tern and western snowy plover
California clapper rail
Salt marsh harvest mouse
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Trapping Implications
 Bobcat live cage trapping is the most
effective means of mitigating this main
impediment to T&E species recovery.
1
 Trapping is the only viable means to control bobcat populations,
accounted for 73% of all bobcat take.2
 Trapping does not harm other wildlife populations.
 Trapping of bobcats is selective by sex, males only taken
(females and young released alive unharmed.)
 Annual trapping records quickly monitor bobcat population
trends. CDFW’s main accepted method.2
1. Wengert, G. Trends in Fisher Predation in California. 2011
//////
2. Garcia J. Bobcat Harvest Assessment 2014-2015. 2015
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Trapping Implications
 Three main trapping options:
 CDFW staff trappers – un-budgeted taxpayer $$, staff?
 USDA APHIS – uses taxpayer $$, scarce staff allocated
 PRIVATE TRAPPERS – little, if any, use of taxpayer $$,
no government trapping staff needed, PLUS trappers
pay license fees into state coffers, PLUS trappers are
main eyes and ears in the field to report poaching to
wardens reducing the number of DFW wardens needed
to patrol, PLUS private trappers make biggest impact
by trapping all over the state daily for an entire season.
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Request to Commission
 Reinstate bobcat live-cage trapping
seasons in California
 In light of this new, significant scientific biological
information regarding major adverse bobcat predation
impacts which jeopardize the continued existence of
numerous threatened and endangered species and
species of special concern.
 Trapping is the most effective tool available to CDFW and
the Commission to control bobcat populations in order to
protect these imperiled species and aid their recovery.
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Works Cited

Wengert, G. Trends in Fisher Predation in California. 2011.

Wengert, G. Ecology of intraguild predation on fishers (Martes pennanti) in
California. 2013.

Sweitzer, R. and Barrett, R. SNAMP Fisher Study: Sources of Mortality. 2009

Halsey, S. Modeling predator habitat to enhance reintroduction planning. ​2015.

Spencer, W., et al. Southern Sierra Nevada fisher conservation assessment. 2015

CDFW Status Review Report Pacific Fisher, May 12, 2015

CDFW Petition Evaluation Humboldt Marten, Oct. 13, 2015

CDFW, Garcia J. Bobcat Harvest Assessment 2014-2015. 2015

USFWS, Predation on Humboldt marten 2015

USFWS, Pacific fisher assessment, 2015
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Works Cited, cont’d

Benedict, Forbes, San Joaquin Kit Fox, 1973

Berry, Harris, San Joaquin Kit Fox, 1987

Standley, Berry, O’Farrell, Kato, San Joaquin Kit Fox, 1992

Stone, Humboldt marten predation in Oregon, 2010

Slauson, Humboldt marten predation study, 2014

Bailey, Oregon State University, Humboldt marten study, 2014

Ellis, Schemnitz, Food items in bobcat stomachs collected in OK, 1958

Lockyear, ZB et al., Sage grouse nest predators in NW Nevada, 2013

USDA APHIS, FONSI predator damage management to protect endangered Sierra
Nevada bighorn, 2000

San Diego Zoo, Desert tortoise study, 2012
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