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Native Californian, biologist, wildlife conservation consultant, retired Smithsonian scientist, father of two daughters, grandfather of 4 small primates. INTJ. Believes nature is infinitely more interesting than shopping malls. Born 100 years too late.

Tuesday, January 13, 2015

Return of the Fisher

The football game wasn't going my way; so I decided to get physical and pull 3 cameras that had been soaking in the rain.

I headed up Skyway, parked the truck, mountain-biked a couple miles, surmounted a blow-down across the trail, and fell on my butt on the way down the ravine.

The first camera was dry, but three bears had bumped it off target during a  bumble-fest of scent-rubbing.

The news from the second camera was good and bad.

The bad news was the water in the case; it shorted a circuit and shuttered pictures like a machine gun.

The good news was a photo of a radio-collared fisher.

And the camera in the next ravine had more pictures of the same critter.

Discovering the scent lure
A good thing has happened.

California Department of Fish and Wildlife, the US Fish and Wildlife Service, and Sierra Pacific Industries (SPI) have joined forces to restore the fisher to the northern Sierra Nevada.

This radio-collared animal might be one of 40 fishers that were translocated from the northwest corner of the state to SPI land near Stirling City.

But it could also be one of the 48 offspring born to the colonizers over the past three years.

The historical occurrence of fisher in California has been a puzzle.

California's great academic naturalist, Joseph Grinnell, assumed fishers ranged throughout the Sierra Nevada.

Since Grinnell's time however, fishers were found to be missing from a 420 km section of the northern Sierra Nevada.

This "dead zone" is an enigma, because the habitat seems to have everything a fisher needs . . . a fisher-friendly climate, lots of trees, water, cover, squirrels, and maybe even a few porcupine.

Biologists have assumed that logging and trapping divided the population, leaving one in the southern Sierra Nevada and the other in the Trinity Alps and coastal mountains of NW California.

A recent study based on DNA from museum specimens and living animals tells a different story.

California's fishers became divided populations about 1000 years ago.

In other words, we can't blame the fisher gap on the Spanish colonization of California and the gold-lust-mayhem of the 49ers.

Fur trapping and intensive logging in the early 1900s, however, caused the continued decline of fishers across North America, and in 1946 California was the last fisher range state to enact protective legislation.

The two populations are now genetically different, which raises questions about their conservation.

Like, should we connect the northern and southern populations, and risk genetic pollution of their gene pools?

Or should we colonize the gap with fishers and brace the population against future environmental unknowns?

I rather like the idea of filling the fisher gap. California's just an experiment, isn't it?

Having a few more fishers around makes the place more interesting.


Grinnell, J. 1913. A distributional list of the mammals of California. Proceedings of the California Academy of Sciences, 3:265-390

Grinnell J, Dixon JS, Linsdale JM (1937) Fur-bearing mammals of California: their natural history, systematic status, and relations to man. University of California Press, Berkeley. 375 p.

Powell, RA. 1993. The Fisher, life history, ecology and behavior. University of Minnesota Press, Minneapolis. 237 pp.

Powell, RA,  RC Swiers, AN Facka, S Matthews, and D Clifford. 2013.  Reintroduction of Fishers into the Northern Sierra Nevada of California,  Annual Report for 2013 For the period of October 2009 to December 2013, 35 pp. 

Tucker, JM, MK Schwartz, RL Truex, KL Pilgrim, and FW Allendorf. 2014. Historical and Contemporary DNA Indicate Fisher Decline and Isolation Occurred Prior to the European Settlement of California. PLOS One 7(12):1-13


Gabriel, MW,  et al. 2014.  Anticoagulant Rodenticides on our Public and Community Lands: Spatial Distribution of Exposure and Poisoning of a Rare Forest Carnivore. PLOS One 7(7): e40163. doi:10.1371/journal.pone.0040163

Zielinski WJ, Kucera TE, Barrett RH (1995) Current distribution of the fisher,

Martes pennanti, in California. Calif Fish Game 81: 104–112.


john said...

A very informative post. Congratulations on getting those photos.
I wonder about what other factors are at work that limit the natural range of Fishers. I also wonder whether these transplanted Fisher populations will survive in the long run?

Woody Meristem said...

Pennsylvania reintroduced fishers a number of years ago after having been extirpated during the days of heavy logging and unregulated trapping. The population is now thriving and has occupied suitable habitat far from the reintroduction sites.

They are an interesting species and more adaptable than many of us thought.

Anonymous said...

Great photos of the Fisher. An historic factor in the loss of some of the rarer carnivores, particularly in the west, could be the result of wide-scale poisoning of predators carried out in the 1920s and 30s. Federal (Bureau of Biological Survey) and State predator control agents broadcast small poisoned baits on State, Federal, and private lands including National Forests and National Parks. They also put out poisoned grain to kill rodents and these poisoned rodents, in turn poisoned the scavengers including the smaller carnivores—a real mess. Many ranchers and farmers were complaining that there was little or no fur to trap (a source of rare dollars for near-subsistance rural folk). First predator and rodent control agents killed off the predators resulting in population release for rodents—so then they had to kill off the rodents.
Best wishes,

Nograyhere said...

Old codger, you are my favorite part of the internet.

christian said...

Awesome post all around.

I dig their radio collar, like an elegant little bow tie.

John W. Wall said...

If the gap is suitable habitat, what's to stop them from expanding into it? Maybe establishing wildlife corridors would do the trick.

Camera Trap Codger said...

Having driven through the northern Sierra many times, I'd say it doesn't look like there's a forbidding barrier in sight. But the tools for making such calls these days are much more sophisticated than eyeballing habitat from one's car.

Lucas Machias said...


Saw this looking for directions on making a fisher house

Camera Trap Codger said...

Thank you, Lucas. I'll be following Aaron's blog from here in out. Great news to learn about evidence of porcupines in the area. Back in the 60s they were common in the region --especially in Plumas County.

Camera Trap Codger said...

Thank you, Lucas. I'll be following Aaron's blog from here in out. Great news to learn about evidence of porcupines in the area. Back in the 60s they were common in the region --especially in Plumas County.