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September 17, 2010
DENVER, CO - Colorado Division of Wildlife Director Tom
Remington announced today that the state's lynx reintroduction
project had accomplished its goal of establishing a breeding
population in the Southern Rockies and that biologists are now
transitioning to monitor the cats' long-term persistence in
Colorado's high country.
The announcement comes following the discovery this spring of 14
lynx kittens in five separate dens, including the first two dens
documented in Summit County, outside the core reintroduction area.
As only some breeding-age female lynx are equipped with satellite
collars, the 14 kits represent the minimum number of lynx births
this year.
Between 2003 and 2010, researchers documented that at least 141
lynx kittens were born in Colorado. Analysis of observational data
indicates that the cats' reproductive rate has outpaced mortality
in the 11 years since the reintroduction program was launched,
which is the hallmark of a self-sustaining population. DOW
biologists believe lessons learned from this program could be
helpful in developing a plan to reintroduce wolverine to Colorado.
Gov. Bill Ritter hailed the success of the reintroduction project.
"Protecting and enhancing Colorado's wildlife heritage takes hard
work and dedication," said Gov. Bill Ritter. " I commend the
Division of Wildlife for this accomplishment. It's an example of
what we can do when we have a vision and the will to see it
through."
Remington said the lynx project is one of the most ambitious and
significant state-led reintroductions in recent years.
"The Division of Wildlife has a long tradition of restoring and
recovering native species in Colorado," Remington said. "This is a
tradition that ranks among the Division's finest achievements. I
applaud the wildlife professionals whose commitment and expertise
have made the lynx project a success. Today is a proud day for the
agency."
The DOW began reintroducing lynx in 1999, releasing lynx captured
in Alaska and Canada into the remote San Juan Mountains in
southwest Colorado. From 1999 to 2006, the DOW introduced a total
of 218 lynx, monitoring radio- and satellite-collared lynx as they
colonized the core area and expanded their range into other parts
of Colorado's high country. The mid-sized lynx has proved adept at
adjusting to Colorado's rugged mountains, finding both food and
habitat necessary for successful reproduction in at least six of
the past eight years.
Lynx reproductive rates have varied greatly since kittens were
first documented in 2003. After den visits identified 16 kittens
in 2003, researchers found 39 kittens in 2004; 50 kittens in 2005;
11 kittens in 2006; 11 kittens in 2009; 14 kittens in 2010. During
the 2006, 2009 and 2010 seasons, DOW field crews documented that
Colorado-born lynx had successfully produced third-generation
Colorado kittens. In 2010, researchers estimated that between 30
and 40 percent of female lynx bore litters of kittens.
DOW biologists suggest the lack of documented reproduction in 2007
and 2008 and the variability in the number of kittens produced by
collared females year-to-year is consistent with what researchers
know of lynx populations in their traditional strongholds in the
northern boreal forest. There, lynx populations track the cyclical
abundance of snowshoe hares, the primary winter food source for
lynx. Numerous studies in Alaska and Canada document that lynx
reproductive success oscillates with snowshoe hare numbers. DOW
researchers say 2007 and 2008 represented low years in snowshoe
hare abundance in Colorado.
Biologists also documented the Colorado lynx population's ability
to successfully target their traditional secondary food source,
red squirrels, in times of snowshoe hare scarcity. In 2009, scat
analysis suggested squirrels made up 66 percent of lynx diets.
"What we've seen from lynx in Colorado is exactly what we'd expect
to see from lynx in their northern habitat," said retired DOW
biologist Tanya Shenk, the lead researcher on Colorado's lynx
project from 1999 to 2010. "This supports our strong belief that
the habitat in Colorado will sustain lynx over the long term."
However, biologists caution that climate change, events such as
wildfires and bark beetle epidemics along with future development
could alter key portions of potential lynx habitat in Colorado in
unforeseen ways. To track the lynx population, biologists will now
pursue a site occupancy monitoring strategy, using minimally
invasive techniques like trail cameras, snow-tracking and genetic
sampling to monitor the presence or absence of lynx in established
and potential habitats. This will replace the strategy of
capturing and collaring individual lynx to gain detailed knowledge
of their movements, habits and fate. The new approach will give
biologists a better understanding of the lynx population
throughout Colorado, although yielding less data on individual
cats.
"This is a more cost-effective strategy that avoids subjecting
individual cats to the stress of capture," said Scott Wait, DOW
Southwest Region senior biologist. "But it will give us a better
way to track the persistence and hopefully expansion of lynx
populations."
"We've done everything necessary to restore lynx to Colorado,"
added Rick Kahn, the retired DOW terrestrial resources manager who
spearheaded the reintroduction program for over a decade. "Now
it's up to the cats to continue to respond as they have for the
past 10 years."
Colorado launched its reintroduction program despite the
possibility that lynx would be added to the federal Endangered
Species List. In 2000, the lynx was listed as threatened under the
ESA due to their inadequacy of existing regulatory mechanisms to
protect the species and its habitat in the contiguous United
States. DOW officials will continue to work with the Fish and
Wildlife Service to define federal benchmarks for the continued
recovery in Colorado -- such as the creation of a Recovery Team
and a Recovery Plan for lynx in Colorado and nationwide.
The Colorado Lynx Reintroduction Program required the support of
numerous personnel in the DOW, other state and federal agencies,
the Colorado General Assembly, the administrations of three
different governors and the general public. Such sustained
dedication has resulted in the successful reintroduction of this
species to Colorado's ecosystems. Funding for the reintroduction
program was provided by Great Outdoors Colorado, Vail Associates,
the Colorado Wildlife Heritage Foundation, the Turner Endangered
Species Foundation, the U.S.D.A. Forest Service, private donations
and the DOW.
To view a detailed summary of Colorado's Lynx Reintroduction
program, please visit the following link:
http://wildlife.state.co.us/Research/Mammal/Lynx/
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