Winter weasel without snow

I finally got it:  I cam-trapped a weasel in its dashing white winter camo.

But as you’ve noticed, it’s sticking out like a sore thumb because there’s no snow 2 feet underground where the picture was taken.

I’ve wanted that photo since I learned that weasels are frequent but uninvited guests in mountain beaver tunnels.     

Wouldn’t it be cool to show a winter weasel without the benefit of its winter backdrop of snow?

How do you get that picture?

You can nature-fake it – just live trap a weasel (no small feat) and photograph it on soil and leaf litter set in a cage.

Or you can set a camera in a mountain beaver burrow.

But there’s risk and a technical challenge to leaving a camera underground in a rodent burrow for half a year.  

You have to supplement the camera’s normal battery power so it can take flash photos for 6 months. (I wired 4 external batteries -- 2 D and 2 C cells -- to the camera for back up power, and used 2 9-volt batteries to power the controller.)

And you have to retrieve your camera before spring snowmelt floods the burrow and drowns the camera or buries it in silt.

I was ready to deploy in the fall of 2013, but procrastinated, and the snow shut me out that winter.  

I procrastinated again in 2014, but it was a drought year, and I got away with setting the camera in early November.

Disappointment came the following May when I discovered the batteries died 45 days into the bargain and before any weasel made an appearance.  Murphy’s Law.  

Last winter I had the camera in the ground on October 7^th. 

The camera had been out 8 months when I drove to the site a couple weeks ago with Bill and Diane Wilson. 

Our timing seemed okay. The snow was gone at 6000 feet, and the Forest Service road was dry.  The only thing that was worrisome was the Yuba River, which was already roaring from snowmelt.

At 7000 feet snowdrifts blocked the road.   

“Wait here Bill, I think it’s within walking distance.”

I skirted the drifts on the road, but it was solid snow at the creek, which was a choppy gusher.

This was not a good sign because the camera was in an alder thicket on a silt bench a few yards from the creek and only a few feet above water in summer.

A few minutes later I found the alder thicket; normally 8-15 feet high, it was flattened by snowpack.  

I’m standing there thinking it would take a team with shovels and spuds to expose the camera, when I see a bare spot and a piece of weathered plywood.

It was the cover over the tunnel and camera.

I tugged it free like a crazed treasure hunter . . . and “Damn (expletives deleted)!”

The tunnel was flooded.

I yanked the stake free with the camera attached . . . and “DAMN! (more expletives deleted)!”  

Rust-colored water drained from the camera case.

I pulled the precious SD card, dried it, and headed back to the car with the dripping camera trap.

At San Francisco State University’s field campus we downloaded the file.  

The camera took 106 photos before unseasonal rain flooded the burrow at the end of January.

I was resigned to another failure as we scrolled through blank exposures and occasional pictures of vole, shrew, or chickaree.

Then the snow-white weasel appeared. On January 7^th. One image.

It was the last animal picture on the card.

Three weeks before the flood that ruined the camera.

     

Little Earthmover

Little Earthmover

Ever wonder what a mountain beaver does outside of its burrow?

No?

I guess I'm not surprised. 

Well, have a look anyway.

Here's some footage of a mother and her offspring taken during last summer's Camera Trapping Workshop in the northern Sierra Nevada.

There's not much to say.

Mountain beavers are just like big pocket gophers when it comes to moving earth. 

Slinky grim reaper of the underworld

Long-tailed weasel with prey.

There's a good reason weasels are long and skinny.

It's "essential to the profession of a burrow-hunting rodent predator...", wrote weasel expert Carolyn King.

This photo of hunter and quarry was taken in a mountain beaver burrow, and it would seem to prove the point.

But did this long-tailed weasel kill the golden-mantled ground squirrel in the burrow?  Or did it dispatch the rodent above ground and then drag it into the burrow?

Golden-mantled ground squirrels are common in the area, but you find them in dry open coniferous forests rather than the riparian woodland and thickets where mountain beavers dig their burrows.

I've camera trapped this mountain beaver burrow almost seven months in the past 4 years, and the graph shows that golden mantled ground squirrels are not among its users.

I suspect the weasel killed the ground squirrel above ground and dragged it into the burrow to feed out of harms way. That's how weasels operate.

But as the graph shows, a weasel is more likely to encounter a mountain beaver in this burrow than a golden-mantled ground squirrel, and the chickarees and voles down there certainly run the risk of meeting this slinky grim reaper as well.

One other observation: the camera failed to record the resident juvenile and adult mountain beaver during the last sampling period. At least one mountain beaver has always been present.

Has the weasel appropriated this mountain beaver's underworld?

Is its nest now lined with the soft pelts of the previous residents?

I'll update you next month.

A chickaree shells a fir cone in the underworld earlier this month.

Reference:

King, C. 1989. The natural history of weasels and stoats. Cornell University Press, Ithaca.

Errant Mountain Beaver

Folks up here on the ridge were recently roused to declare their biophilia when a mountain beaver was reported swimming down the Butte Creek Flume.

One of our local naturalists, a retired bike-riding school teacher known by his avatar Forest, documented the rare event in video.

This is the first verified record of mountain beaver in Butte County, and the discovery begs the question: From whence the errant rodent?

I'm an enthusiast of these guinea pig size rodents, and I recognize their haunts when I see them, but I have never seen their signs in the county of Butte.

They require lush vegetation for food and live in moist habitats with shallow water tables, Their burrows often tap into underground springs.

I guess I have to look a little harder.

Arctos, an extensive database of zoological records, lists mountain beaver specimens from several counties in the Sierra Nevada, including Shasta, Plumas, Eldorado, Sierra, Nevada, Placer, Mono, Mariposa, and Tulare.

I suspect this particular rodent entered the flume voluntarily, swam around, and went with the flow.

But here's the rub. Its flume float could not have been longer than about 3 miles.

If the rodent had embarked on its swim further upstream it would have passed into a deadly siphon that conveys the water down and then up a ravine.

Even Houdini couldn't have made it through that siphon alive.

If the mountain beaver's odyssey started above the siphon, it had to travel by land to bypass the siphon and reach the flume's navigable portion.

Unfortunately, the neighborhood's flumes do not lead to suitable habitat for mountain beavers. So I doubt this rodent's trip led it to greener pastures.

It was an unusual event and it makes you wonder.

Did the mountain beaver abandon its home because of the drought? Or was it just a normal attempt to disperse that few people ever see?

We're lucky to have naturalists like Forest here.

Video vision in the tunnel - Part 2

Our first attempt at subterranean video this year was disappointing.

Had the camera been placed differently the footage could have been better, but there was also the problem of the curious bear cub that dismantled the set.

The subterranean action however was more than enough to call us back.

Our second attempt in August was in a different segment of the same mountain beaver (=showtl) tunnel.

This time I came prepared with a customized mount that could be spiked into the hardpan on the floor of the tunnel and nailed into the log embedded in the silt bench above the tunnel.

Set 519.3 after being disguised
with a large flake of red fir.

The camera post was spiked and wired
to the embedded log. 

We covered the vertical hole with a large flitch of wood.

As you have seen in Part 2, the bear didn't show, and if any subterranean critters bumped into the camera they didn't move it.

















But I still didn't get the angle of the camera quite right. It should have been aimed up into the tunnel. The focus was also off, and the microphone made hideous sounds (which I'll try to remove -- sorry about that).

The camera in situ as we uncovered it
33 days later.

I just replaced the lens of the DXG 567v with a 4mm wide-angle CCTV lens, which will take in a much wider view.

We'll try again next spring.

The Restless Haystack

A mountain beaver or showtl on the job -- is it making hay or pitching its tent? 

In 1995 Mark Johnson published an article on tents that cover the burrows of mountain beavers.

"Supporting sticks were placed over and across the entrances. Then, sticks were placed perpendicular to these over the entrances. Finally, leafy sticks of big leaf maple (Acer macrophyllum), sword fern (Polystichum munitum), or both were placed across the sticks concealing the entrances." 

The tents were clearly the handiwork of the showtls and not the caring gesture of a passing Sasquatch.

Not all burrows had tents, but Johnson thought they may keep burrows dry in a rainy climate.

Though usually agreeable, showtl enthusiasts have at times disagreed about the animal's tolerance of water.

A pioneering student of the showtl, C. A. Hubbard opined that the rodent shuns watery tunnels, "because Aplodontia cares for water only as  a drink."

Lloyd Glenn Ingles on the other hand averred that, "Living as it often does near water, the animal is a fine swimmer."

Yours truly and his student camera trappers have also given photographic proof that showtls and their neighbors have no qualms about scooting through watery tunnels.

I have the feeling that the showtl's tent may be a drying rack for plant cuttings, that is, nothing more than a haystack, and haystacks have also been reported numerous times in the scientific literature.

The big question is about the criss-cross arrangement of the sticks.

Are they an act of God or an act of mountain beavers?

I've assumed they were an act of God, that they just happened to be there as they had fallen from the trees.

We have actually removed a few sticks from some burrows for better pictures, and if the rodent replaced them with others, I for one didn't notice.

But I am greatly intrigued by Johnson's suggestion, though apparently based on circumstantial evidence rather than direct observation.

A rodent that builds a tent or a drying rack by dragging sticks over its burrow is a remarkable rodent.

It's a tool user.

So confirming Johnson's tent-building observation is on the list for next year's showtl work.

If you haven't seen a showtl's haystack, here's a sequence of 30 photos taken during a week near Yuba Pass, California.

Try to stay awake. It's less than a minute and the action gets exciting at the end.

References

Hubbard, C.A. 1922. Some data on the rodent Aplodontia. The Murrelet 3(1):14-18.

Ingles, L.G. 1965. Mammals of the Pacific States. Stanford University Press, Stanford, California.

Johnson, M.K. 1975. Tent building in mountain beavers (Aplodontia rufa). Journal of Mammalogy, 56(3):715-715.

Will the real Ermine please stand up

September 3, 4:39AM -- in the showtl's underworld

We are just back from the north fork of the Yuba River.

Yesterday, the Codger, the Redhead, Audrey, and Fred pulled the last three camera traps, and I am terribly amped.

The picture above is one of the reasons.

You may recall that the codger was uncertain that "Herman the Ermine" was correctly identified in a recent "underworld post".

A few commentors thought the suspect was an American mink.

The unmistakable ermine pictured above confirms that the previous mustelid was indeed Slinky the Minkie.

This ermine was photographed in the same Aplodontia (=showtl) tunnel where the mink made its appearance last month.

To get an idea of the relative sizes of this little predator and its prey, compare the two pictures, which I have cropped more or less to the same size.

Like the mink, the ermine evidently failed to find the showtl, which showed up 6 days later.

Its absence makes you wonder if predator detection changed the rodent's use of the tunnel system.

Anyway, we're not done yet.

We staked out several Aplodontia burrows for camera trapping next year.

Our winter work is cut out for us. We've got to get faster cameras so we can diminish the number of false exposures down there in the showtl's underworld.

There's a lot of traffic and probably a few visitors that are just too fast for our cameras.

And to give you a bigger view of the showtl's busy underworld, here's an uncropped photo.

Showtl's Underworld, Part 2

Six hours after we left, Showtl made its first appearance.  

What a difference a month can make during the growing season.

We bumbled about looking for the underground cams.

Alders in full leaf and knee-high grass covered the landmarks we expected, and we fell back on the GPS and Audrey's cognitive map to find the underground cameras.

But showtl didn't let us down.

Our rodent made almost daily appearances, which means the site was probably located near its nest.

Only 21% of 281 exposures however contained animals. The rest were blank images.

Normally we'd blame this on moving vegetation and phantom puffs of hot air which the infra-red sensor can't distinguish from animals, but this doesn't explain false exposures in the showtl's cool burrow.

It is more likely the rodent was zipping back and forth, and the camera was often too slow to get pictures of it.  

Despite false exposures, we still got 57 images of our quarry, and what you see here are the best. 

What you don't see are the two predators lurking in the tunnel.  

They're coming soon. 

The Showtl's Underworld

My obsession with showtls took a new turn this summer.

We attempted our first subterranean camera trap sets.

Two hours later two cameras were positioned to capture photos of the beastie in its underworld.

The showtl's tunnel was squarely in the middle of an alder thicket, and Montana Carl announced his intention to stay clear of alder, which he claimed had taken liberties with his person ever since the first day of the workshop.

In point of fact, springy alder limbs had been goosing all of us.

Making the sets therefore fell on the shoulders of the more agile young folk, while the two codgers sat on the sidelines to kibbitz.

The first task was to find the best location.

Several cave-ins had left gaping holes, much bigger than showtl burrows, that murmured of water and mosquitos within.

"Who's gonna stick their arm down there and take some pictures of the tunnel?"

Seabass volunteered.

The pictures showed us that the tunnel was anything but straight, and passed through a morass of buried timber and roots.

In some places it was an open trench. 

Next, we had to decide which cave-in gave the best subterranean perspective.

Snow water had created a small cavern immediately inside one of them.

It was an ideal situation for a camera trap: we could stake the camera and yield right-of-way to passing showtls.

Seabass drove a 1" pipe into the bed of the subway, and lowered the cam on its mount to just above the water.

The afternoon dragged on as we fine-tuned the camera's position, but we were all fluffed up with our cleverness, and for good measure we hurriedly staked a second camera down another chute.

Then we headed back to camp for a well-deserved happy hour.

Spring cleaning

We descended on the alder thicket on the Yuba River back in June-- a band of eager camera trappers hungry for photos of the enigmatic but endearing showtl.

When it comes to camera trapping, showtl seems to be on the bashful side.

You have to wait a week or more before the adorable head with humanoid ears pokes out of the burrow.

But this time Bill Wilson got a nice series of showtl pictures over a period of two weeks.

This animal's watery burrow had an apron of knuckle sized rocks, and as you can see in these stitched photos, those rocks weren't washed out by water.

Showtl was doing its spring cleaning, while the plants were growing like crazy.

I wonder how much gold the showtls have unearthed since the 49ers?

Thanks Bill, for letting me show your catch.

Aplodon done gone away

It's always a thrill to get a weasel,

but I was looking for Aplodon (= mountain beaver).

West branch of the Yuba River, Sierra County, California

This wasn't the lush alder thicket I had worked back in early summer. 

The undergrowth was trampled and dry.

Deer had broken the dense clumps of Delphinium, and only a bear could have demolished the red fir log I had used a few months ago as a walkway into the thicket.

But I found the camera trap right away, and expecting an assortment of birds and small mammals I opened it to see if the camera still had power.   

Damned if the batteries didn't work! 

The next move in the ritual is NOT to start viewing the pictures. 

First I check the number of photos to find out if the catch was good or bad. 

What!  Only 4 photos?

That explained why the batteries still had power.

Yes, I was pleased to get the long-tailed weasel.

It is evidence that they forage in mountain beaver burrows, and you have to marvel at a predator that takes down prey 2-3 times larger than itself.

But how could this runway and burrow yield so few photos in a period of 2 months?

Last year the burrows were teeming with activity.

There's always something to learn  from this game and here are my thoughts.

First, I don't think the weasel cleaned out the colony.  

After giving it some thought, I remembered camera trapping  in Point Reyes National Seashore  a couple years ago.

Aplodon burrows that were active in early summer seemed abandoned in late summer. 

In both areas the active burrows were damp and the inactive ones were dry and dusty.

When the soil dries up mountain beavers seem to move to areas where the soil is moist. 

In winter and spring when soil moisture is more uniform they move back into the old burrow systems.  

That's my working hypothesis. 

 

The seldom seen showtl (or aplodon)

I set four camera traps in Sierra county a month before the camera trapping workshop, and was mighty pleased to find that mountain beavers -- hereinafter show'tls or aplodons -- occur in the drainages feeding the Yuba river.

Yes, from here on out I am calling them "aplodons" or "showtls". They deserve a catchy vernacular tag or a name (like "simple teeth") befitting their unique evolutionary position.

Let's forget the term "mountain beaver". Yes, like beavers they are excellent swimmers and waterway engineers, but there the resemblance ends. The name boomer doesn't cut it either. The only report of such a sound is now over 130 years old.

Then there's the name "sh'auch" used by the Indians of Puget Sound. It meant "creature that creeps in the undergrowth", and you can guess why that didn't take. The other moniker -- "sewellel" -- is said to have been the Indian term applied to robes made of their furs.

Enough. Back to the workshop. . .

When it commenced on July 21, the cams had been in the field for a month. Knowing that camera trapping is often slow business, I wanted to fire up the class at the outset by showing them the seldom seen showtl.

The gamble paid off. After I had rambled at length the first morning about camera trap sets and camera attachment methods, we climbed into the nearby thicket, found the cam, and clicked through the pictures.

A beady-eyed rodent finally appeared in the LCD, and being topless, she disclosed her sex within the first few pictures (notice that I don't confuse sex with gender). We didn't realize this until she was displayed on the computer screen.

The fact that she was bare-breasted has special significance. Female aplodons have very hairy nipples when cycling, pregnant, or lactating. We're talking about "dense patches of black hairs". Though a sign of showtl womanhood and of certain adaptiveness, it is not an enviable trait. It's likely that this bare-nippled girl was born this spring.



Aplodon colonies in this part of the sierra are in sprawling alder thickets bordering the Yuba river and its tributaries. We found numerous nipped twigs of alder, but the pruned stubs were dry and gray. I was almost convinced that alder is a springtime food until we found a burrow with leafy wilting branches.



Lewis and Clark were the first to report on aplodon's climbing ability, but University of California mammalogists Joseph Grinnell and Tracy Storer had their doubts. Lloyd Ingles proved it with photography.

Ingles built an enclosure at Huntington Lake in the southern sierra, and stocked it with two females from a nearby colony. They climbed 20 ft up into white firs and lodgepole pines, and in 4 weeks pruned off most of the branches. Aplodons are respectable if not acrobatic climbers of trees and shrubs, but they have to descend butt-first.



I thought that aplodons would be easy pickings for the workshop participants, but I was wrong. No one else got their photos.

When I checked the date and time stamps on my own pictures I realized why. The animal had visited the burrow only on three occasions, and the first visit wasn't until three weeks had passed. Aplodons have extensive burrow systems with multiple openings.

During the course I tried to get more photos by planting my small camera traps in underground tunnels with caved in ceilings. Every sign indicated they were active tunnels, but no aplodon showed it face.



References

Camp, C.L. 1918. Excavations of the burrows of the rodent Aplodontia, with observations on the habits of the animal. Universitu of California Publications in Zoology 17(18):517-536

Godin, A. J. 1964. A review of the literature on the monjtain beaver. Special Scientific Report -- Wildlife No. 78. U.S. Department of the Interior, Fish & Wildlife Service, Bureau of Sport Fisheries and Wildlife, Washington D.C.

Ingles, L.G. 1960. Tree climbing by mountain beavers. Journal of Mammalogy, 42(3):120-121

Scheffer, T.H. 1929. Mountain beavers in the Pacific Northwest: their habits, economic status, and control. US Department of Agriculture, Farmers' Bulletion No. 1598:1-18

The distraction of fire

You're damn right the codger's been quiet. The Humbolt fire, which started on June 11 was too close for comfort and a lot of good people lost their homes. We packed our bags the first day, and then sat around listening to the radio. The fire started on Doe Mill Ridge as seen above from our place. It crossed Butte Creek Canyon, climbed the next ridge, and swept through lower Paradise, the next town down the slope from us.

Hale and rain arrived 10 days later, but not enough to have an effect. Instead, a spot fire broke out under a power line about a mile away from home, and this is what we saw.



A spotter plane and a tanker showed up that afternoon, and 6 dumps of retardant put it out.

Bearing witness is a helpless feeling, and a lot of strange and foreboding thoughts flash through the mind, but your esteem of firefighters soars.

By Sunday the 22nd, it was time to get away. There was no call for evacuation in our neighborhood, it was just that the redhead was fretting so much. We drove 125 miles to the Sierra Nevada Field Campus to meet Jim Steele and put out some camera traps.

We passed a new fire that had just started in the lower Feather River Canyon, and just beyond Quincy we saw this. No, those are not clouds.



SF State's field campus was well beyond the lightning strikes. It was a lovely afternoon, and we set four camera traps.



I couldn't resist placing two in an alder thicket.



The signs of mountain beaver were everywhere.

One good thing has come out of the smoke and fire. I've been housebound and busy hammering out a camera trapping manual for the workshop in a couple weeks.

Red Sally, the cold blooded night stalker

October 25, 7:27PM: We are back at Point Reyes National Seashore again, where a cold blooded night stalker padded past the camera looking for edible victims in the leaf litter.

This record of an Eschscholtz salamander (Ensatina eschscholtzii) was a stroke of good fortune. The camera's passive infrared (PIR) sensor does NOT respond to cold moving bodies. A warm moving body -- brush rabbit, deer mouse, or wood rat -- must have triggered the camera just before the salamander moved out of the frame. Whoever it was, I am grateful.

Ensatina, a salamander without lungs . . . I remember it well from collecting forays on the San Francisco peninsula. Its fruity (ripe persimmon) complexion, laterally compressed tail, and constricted tailbase give it away as the yellow-eyed subspecies xantoptica -- commonly called the red salamander.

Red Sally's fiery coloration reminds some predators of bad dining experiences. It is believed to trick birds by looking like a newt. It is a mimic of newts. We have three species of newts here, and all of them have skin laced with tetradotoxin, the same stuff that makes pufferfish deadly poisonous. Birds that have gagged on toxic newts are tricked by Red Sally the imitator. But the salamander probably doesn't fool snakes, that have limited color vision, but a powerful Jacobson's organ.

Red Sally chooses a subterranean existence until the fall rains. Ninety-four years ago and not far from here the California naturalist C.L. Camp found a red salamander nest 2 feet deep in a mountain beaver burrow. Why not? Coastal scrub offers little in the way of ground cover and fallen logs, but mountain beaver burrows and woodrat nests offer a stable microclimate and plenty of insects, though they don't guarantee freedom from predators.

Stebbins notes that "When the surface is damp and temperatures not too high, considerable time is spent above ground where most feeding probably occurs." That's probably what Red Sally was doing here.



References

Stebbins, R.C. 1951. Amphibians of Western North America. Berkeley and Los Angeles.

http://www.santarosa.edu/lifesciences2/ensatina2.htm

Hark, the Mountain Beaver

Hark to the mountain beaver, one of California's most mysterious and best kept secrets. It's not a beaver, and it doesn't live exclusively in the mountains. So . . . you may want to call it by its other name --boomer. Not that that is any better, because they don't "go boom" either.



We should take pride in this lovely, furry muskrat-sized rodent with a stub-tail. It's a living fossil and a unique American mammal. Aplodontia rufa is the only member of its family, the Aplodontiidae. Its ancestral relatives were digging up the Great Plains back in the Late Oligocene and Miocene, and were related to the Mylagaulids, which were more diverse and included the horned gopher -- Ceratogaulus of the Great Plains. That makes the mountain beaver a sole survivor of a once diverse assemblage of rodents.

Until a few weeks ago I knew the species only from the plush furs of museum specimens and the literature. But I always wanted to know the animals in the flesh, so to speak. My chance came this spring when the National Park Service approved my application to do a camera trap survey of wildlife in Point Reyes National Seashore.



The coastal scrub of California seems an unlikely place for mountain beavers. They live in lush conifer-shaded creekside habitats in most of their range, and usually on steep slopes. In addition to the main populations in the Sierra Nevadas and Cascades, California has two small isolated populations at Point Reyes (285 sq. km.) and Point Arena (62 sq. km.). These are in the fog belt of the north coast.

These island populations were obviously connected at some point in the past. As recently as about 3,000 years ago, mountain beavers lived betweeen these two sites. Gnawed bones from Duncan's Point Cave tell us that carnivores were catching them there near the mouth of the Russian River.

During a state-wide distributional survey of mountain beavers, biologist Dale Steele also discovered an even more unlikely habitat in the alkali scrub of Mono Lake. This truly looks like a no-mans-land for mountain beavers, because water limits its distribution. Unlike other rodents, mountain beavers are unable to produce a concentrated urine by resorbing water, because their kidneys lack the loops of Henle which perform this function. They need plenty of free water and succulent vegetation to survive.

Nonetheless, there they are at Mono Lake, pocketed in an oasis with a questionable future. I don't think it is known whether these particular mountain beavers are brave recent colonizers, or old stragglers from earlier and wetter times.

The coastal scrub at Point Reyes on the other hand is sodden during the winter and spring, and fog-bathed in summer and fall. The coastal scrub forms impenetrable thickets of coyote bush, blackberry, Euonymous, poison oak, cow parsnip, and thistle (among others). Here and there deer and elk have blazed trails through the stuff, which brings coyotes and bobcats a little closer to the mountain beavers' inner sanctum. But I got a clear impression that only smaller predators like weasels, skunks, and perhaps gray foxes can penetrate the tangles to the heart of boomerland.

When wildfire burned 5000 acres of Point Reyes's habitat in 1995 wildlife biologist Gary Fellers and co-workers discovered that mountain beavers were more abundant than previously estimated. With home ranges no larger than a half acre and a fairly tolerant disposition, quite a few can pack into an area, but for the most part they are hidden in the thickets.

During 27 camera trap days, the cameras made 858 exposures of which 31% contained animal images. Of the 8 species photographed, mountain beavers were in only 7% of the photos, and most of them looked like this.



I am not satisfied. I want a full-body shot worthy of a centerfold. Clearly I need more time to catch the boomer disporting itself out of its burrow.



Acknowledgement:
Many thanks for the cooperation of Point Reyes National Seashore, National Park Service. I am grateful for the assistance of Drs Ben Becker (NPS) and Gary Fellers (USGS).

References:
Beier, P. 1989. Use of habitat by mountain beaver in the Sierra Nevada. Journal of Wildlife Management, 53(3):649-54.

Carraway, L.N. and B.J. Verts. 1993. Aplodontia rufa. Mammalian Species, No. 421, 1-10.

Fellers, G.M, D. Pratt, and J.L. Griffin. 2004. Fire effects on the Point Reyes Mountain Beaver at Point Reyes National Seashore, California. Journal of Wildlife Management, 68:503-508.

Martin, P. 1971. Movements and activities of the mountain beaver (Aplodontia rufa). Journal of Mammalogy 52(

Steele, D. T. 1974. An ecological survey of endemic mountain beavers (Aplodontia rufa) in California (1973-83). State of California, The Resources Agency, Department of Fish and Game. 51 pp. (pdf)

Steele, Dale. Mountain Beaver (Aplodontia rufa) Journal

Wake, T.A. 2006. Archaeological sewellel (Aplodontia rufa) remains from Duncan's Point Cave, Sonoma County, California. Journal of Mammalogy 87(1):139-147.