About Me

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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.

Sunday, July 31, 2011

Herman the Ermine was alurkin'

Herman the Ermine after cropping

"Study your photos carefully", is my codgerly counsel to novice camera trappers. "Its easy to miss the little guys."

As I gleefully reviewed Bill's showtl pictures the other day I failed to notice Herman the Ermine lurking in the background.

This afternoon Herman finally caught my eye.

Here's the uncropped photo, taken two and a half minutes before Showtl appears in its burrow.


Herman the Ermine before cropping

It could have been a close shave.

We've gotten three photos of weasels (long- and short-tails) in the North Yuba watershed, and they've all been in Aplodontia colonies.

This got me to wondering.

How does the showtl avoid or fend off fatal encounters with predators that can enter their burrows?

Does it have any anti-predator ploys?

You just don't see earth-blocked burrows in showtl colonies.

They don't have the pocket gopher's compulsive burrow-plugging habit which seems to hold many predators at bay.

In fact, from the number of burrow openings you'd think they had an open-door policy with weasels.

Here's a sketch of the burrow system and openings from Charles Camp's study of Aplodontia in 1916.




The strange reality is that showtl knows how to block burrows, but reserves the measure for its underground leaf and root pantries.

Camp wrote,
"A singular habit has been noticed in connection with the storage of food. In a burrow excavated at Point Reyes the entrances of two of the food storehouses were found plugged with large pellets of earth evidently manufactured by the animal for this purpose. These earthen balls were one to two inches in diameter and very hard and dry, evidently from being handled a good deal. It is curious that the outer burrow entrances are not similarly plugged." 
Here's a hypothesis.

Short sections of water-filled tunnels, a water seal of sorts, may bar weasels from entering the showtls nest cavity.

Camp didn't describe such water seals, but if we examined more burrows we might find that they exist.

The problem is that recreational burrow-diggers are hard to find these days.

But one thing is certain. The weasel that nails a showtl is well fed for several days.

An adult showtl outweighs an adult male long-tailed weasel by a factor of 3 or 4.

Herman the Ermine is 1/16th the size of the rodent, so the windfall of flesh would be much greater.

But do ermines take down showtls?

I suspect so, at least young ones.

An ermine is a fierce little killer, and if it can wrap its jaws around the showtl's throat the struggle would be brief.

Showtl emerged 2.5 minutes after Herman moved through

References

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

Wednesday, July 27, 2011

Spring cleaning

video


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.

Sunday, July 24, 2011

Sunrise showtl


Dawn chorus and showtl appears
in scattered light of frond and leaf
Through the firs sunlight breaks


As Codger followers by now realize, I am just back from a week at SF State University's Sierra Nevada Field Station, where images of showtls have moved me to feeble attempts at poetic expression. 

The class discovered their camera-trapping instructor was obsessed with the showtl, and if you don't know anything about mountain beavers, sewellels, showtls or Aplodontia rufa, read here.

And by the way, this image was the first attempt at showtl espionage by the ladies of the class.

I'd say they did pretty well. 

As I wind down and unpack, I'll be working up the images.

More on the workshop this week, and thanks to Carl for photoshopping this problematic image.

(Now I am off to the flume where I lost my glasses this afternoon.)

Sunday, July 17, 2011

Young fluffies



We baited this set for small carnivores of the four-legged warm-blooded variety, and that's what we got.

But in addition a pair of young fluffies showed up and used the rocks as a perch.

They seem to be finishing their molt.

As Hans Peeters remarked in Field Guide to the Owls of California and the West, juvenile western screech owls have a loose-feathered look until they molt into their adult plumage.

It's that young fluffy look that makes immature owls so appealing.

Tuesday, July 12, 2011

Bob-tailed possum



Ever surprised an opossum?

If so, you watched it trundle away at a leisurely pace.

When a possum beats a hasty retreat it is not a feat of swiftness, because Br'er Possum is neither built nor wired for speed.

The books that cite 7 kilometers per hour as the opossum's max don't mention that Possum probably never has to go all-out for a mile.

If overtaken by a pursuer Possum plays possum.  

Collapsing, drooling profusely, evacuating bladder, colon and anal gland is no small feat of physiological multi-tasking.  

The hungry predator doesn't have to fight for dinner, because dinner appears to be close to death.

Lying there with that silly grin, Possum blithely faces death with the far-off stare of a meditating yogi; indeed its respiration and heart rate decrease.

But the summation of the stimuli emanating from this hot heap of flesh is enough to make at least some predators lose their appetite.

Playing possum however is an anti-predator ploy that develops with time.

It is not in the weanling possum's bag of tricks, at least not in its full-blown manifestation.

That may explain why the little guy in the picture is missing its tail.

Whatever happened, it was lucky to get away.




Reference


Gabrielson, G. W. and E. N. Smith.  1985. Physiological responses associated with feigned death in the American opossum. Acta Physiologica Scandinavica, 123(4):393–398.  

Sunday, July 10, 2011

The number 6 grizz catcher



Grizz traps -- god-awful devices and troubling reminders of the past.

Gone are California's grizzlies, and gone are the absent-minded vaqueros who undoubtedly stumbled into those gaping jaws of steel hidden in the chaparral.

And woe betide any latter day codgers who play Russian roulette with such deadly toys.

Have you noticed that those springs are wired open?

Well, that's why. Codgers and teen age boys are attracted to such things.

According to A.R.Harding's Project Gutenberg EBook of Steel Traps:
"This is known as the No. 6 or Grizzly Bear Trap and has a spread of jaws of 16 inches. It weighs complete, 42 pounds. This is the strongest trap made. The manufacturers say they have never heard of anything getting out of it when once caught. It is often called 'the Great Bear Tamer.'"
The treadle in the Ebook was simply labeled "No. 6", but this particular one was also stamped with the name of our extinct state mammal:



My friend Paul -- proud owner of a Lickety Splitter, collector of old gadgets, old bottles, old Italian sports cars, and antique tractors among other things -- found it recently at a swap meet.

We get together twice a year, and since we inevitably talk of old things I always ask if he's found any grizz traps.

It's kind of a joke, but damned if he didn't find one, buy it, and give me right of first refusal.

The problem was this -- where do you put a grizz trap?

So I tactfully posed the question. 

"Don't you think it would add a wonderful touch of frontier California to the patio?" 

The redhead didn't agree.

And so I wistfully demurred.

"No problem," said Paul, "I can always find a buyer or swap it for something else."

But he agreed to hold onto it until I stopped by to take some pictures.




A month later we spent a fine day together, and I could tell he was growing fond of the Number 6.

"At our age," he reflected, "you have to decide what you don't need, and what you want to own when you die."

"I think I may just keep it."

"There's a screw-clamp that came with those traps," he continued, "to clamp the springs and open the jaws."

steel trap setting clamp


"I've seen a few for sale, but I never knew what they were."

"I may get one of those too."

A memento of Alta California -- a 42 lb contrivance of spring steel, forged in Massachusetts 130 years ago, shipped to California, forgotten in someone's shed --- has found a new home.

The rest of No. 6's story we will never know.

Friday, July 8, 2011

Ocelot cam-trapped in AZ

Some hunters were cam-trapping in Cochise County, Arizona and got a picture of an ocelot.

You can find the link and other wildlife news items at Outdoor Pressroom, and the article here.

Thursday, July 7, 2011

A sore nose



At least two raccoons muddied their paws at the beaver drag, and this one is missing a chunk of its nose.

I am sure it hurts a lot more than those ticks on its ears..




This is clearly a wound and not a runny nose or a natural discoloration and deformity.

Maybe it was acquired in a scrape with another coon, or maybe Br'er Coon's dinner fought back.

By comparison, this young fellow shows what a healthy nose should look like.

Wednesday, July 6, 2011

Mouse mischief



While the codger was in the field a couple weeks ago the redhead was being a dutiful wife cruising around town in our 20 year old Honda and running errands.

When I got home however she reported somewhat emphatically that she was finished with the Honda.

The story unfolded that our beloved Accord had "gone Nascar".

On her way home it revved mightily and bolted like a race horse

She managed to get it into neutral and pulled over with the engine roaring.

Fortunately a number of gentlemen stopped to offer help, and one of them de-jammed the throttle.

"I'm not getting in that thing anymore", she said.

I started the car up expecting a wild horse ride, but it purred like a kitten, and no amount of foot play could get the throttle to jam.

But my assurances didn't change the redhead's mind, so I took the car to our mechanic and explained the problem.

A day later he handed me a plastic bag filled with acorns and stuffing from the car seats, along with a rodent-chewed air filter.

In all likelihood, he said, some mouse debris had temporarily jammed the throttle.

The redhead still wants nothing to do with it.