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.

Saturday, June 11, 2016

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 7th. 

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 7th. One image.

It was the last animal picture on the card.

Three weeks before the flood that ruined the camera.

     

Tuesday, May 31, 2016

A gob of minced meat


There it is, a gob of minced meat of unknown origin, just as I found it next to a pool in the Butte Creek watershed.

Fred sniffed it tentatively and left it alone.

I photographed it with an 8" crescent wrench for perspective.

Here are some other clues to help you solve the riddle.

It was 2:00 on Memorial Day, temperature in the 90s, and Fred barked several times as we climbed down the slope to the pool on the creek.

Now then, what left the gob of minced meat?




Monday, February 15, 2016

Cookie Monster with Velvet Paws


In the wetlands east of Sutter Buttes there’s a rice farm, and on this farm there’s a machine shed.

It’s one of those open machine sheds where swallows swoop in and out and a pair of phoebes may nest under the eaves.

Since farmers get the munchies, there’s a plastic jar with animal crackers on the workbench.
  
When the staff showed up for work last Wednesday the cookie jar was on the floor.
 
The jar was half empty. Something had pigged out on animal crackers.   

There were no bite marks or signs of brute force, but a cookie monster had managed to twist off the plastic screw lid.

So the farmer set a live trap on Monday, and the next morning the cookie monster’s identity was no longer a mystery.

In the trap was the raccoon's svelte cousin, the ringtail (Bassaricus astutus).

The farmer drove it to a remote area where there was plenty of ringtail habitat and let it go.

Energized by cookies and enabled by velvet paws with retractile claws, it dashed up a tree like magic.


That's a happy ending, I told my friend, but if the rascal comes back, I have a camera trap to see how it opens the cookie jar.

[Many thanks to Tony Rosa for telling me about this event, and to Bill and Susan Shaul and Carol and Frank Rosa for assembling the facts.]

Wednesday, September 2, 2015

A saga of the meat bees

The remains of the hornets nest after the skunk's first visit.

"What's wrong, Silly Boy?"

A bewildered Fred had just slinked into the garage and crawled between the table saw and work bench.  

Yellow jackets were crawling in his coat like raging ninjas, probing for dog hide with their stings.

I dragged him out from his hiding place, slapped the spiteful insects, and stomped them on the floor.

We had coexisted all summer with a nest of "meat bees" next to the house, and I had a hunch that Fred had roused them by scratching a dirt bed near their nest.

Sure enough, they were swarming, and I was their next victim.

Only by peeking around the corner of the house could I survey the ninjas safely.

There was no sign that Fred had been scraping a dirt bed.

Then the ground heaved ominously near the nest entrance.

Was a squadron of killer wasps about to erupt?

The ground lifted several more times, tracing a path away from the nest, and suddenly it dawned on me: 

I had just witnessed a rare event -- subterranean predation!

A mole had torn into the meat bee's underground fortress.

Maybe it had the sweet taste of meat bee larvae on its lips, but this mole was beating a hasty retreat from the yellow warriors.

To prove my supposition, I really should have grabbed a shovel, flipped that mole to the surface, caught it, and taken a picture while fending off the meat bees.

I might have tried it in my youth, but the codger was satisfied to marvel at the image of the mole breast-stroking through dirt with mean-assed meat bees stinging his velvet keister. 

Yes, moles are known to feed on the larvae of underground hornets. The paper mache nest is no defense to a hungry mole that scents a comb of tender wasp larvae.

Anyway, the meat bees had to go, because I wanted to see what the mole had done to the nest.

Neighbor Larry delivered some wasp spray, and the next day I donned my running shoes and zapped the nest entrance.

A few dead wasps littered the ground the morning after, but the ninjas were still coming and going. 

I gamely sprayed again, expecting to excavate the next day.

I was ready to start digging until I heard the menacing hum of meat bees underground. 

I sprayed several more days.

Finally the hive was silent, and I began to scratch away the overlying dirt. 

I found the mole's tunnel, and carefully uncovered the domed gray paper roof of the meat bees' inner sanctum. 

The caress of the rake brought them back to life again! 

It took a full week to annihilate the colony, but the coups d'grace was apparently delivered by a skunk. 

The scene looked like someone had taken a small rototiller to the nest.

I buried the remains of the nest and smoothed the surface, but the skunk dug it up again that night and the next. 

Ah, what a saga . . . Hungry mole attacks nest of meat bees, meat bees mount courageous defense, homeowner and dog become co-lateral damage.

Homeowner vainly wages chemical warfare, and a skunk finishes the job, proving that Old Stinky eradicates meat bees better than moles or the petrochemical industry. 

Wednesday, July 8, 2015

Bagging a little impersonator and other surprises

The shrew-mole, Neurotrichus gibbsii, with its flexible nose-probe in action.








"I'm goin' for shrews", I told my friend Terry who lives in California's Humbolt County.

The fog-bathed redwoods of California's north coast is the land of banana slugs, giant salamanders, red-tree voles, and shrew-moles, among other zoological wonders.

A Sonoma Shrew matches the color 
of redwood duff. 
My assertion that I was going to camera-trap shrews was a bluff.

I was hedging my bets.

I knew Terry's cat, "Muir" periodically catches shrews in the garden, and the cinnamon-colored shrew on the left is proof.


I also knew that kneading sunflower seeds into leaf litter and humus attracts shrews as well as mice and rats, and I submit the photos below as proof.


Sunflower seeds lured these Canadian and Alaskan shrews to my camera traps last summer.  


That afternoon we set camera traps (Sony s600s and Pentax Optio E60) in the redwoods, and the next morning found that the plan had paid off.

The pictures were short on resolution but good enough to identify two of the three "Soricomorphs", or "insectivores" as they were once called.

The Sonoma shrews were easy to identify by color and size.

A Sonoma shrew (Sorex sonomae) face-to-face with a baby millipede
(the pale elongate object in front of it).

The other shrews were either Wandering shrews (S. vagrans) or Trowbridge shrews (S. trowbridgii), which look identical unless you give them dental examinations.

My big thrill however was "bagging" a shrew-mole.

This is the world's smallest species of mole, but it's an excellent impersonator of shrews.

There's no question it's a mole; the quintessential mole-features are there in the teeth, skull, and the absence of external ears.

Its scaly tail with black bristles and constricted base is also decidedly un-shrewlike.

At some point in its evolutionary passage the ancestral shrew-mole struck out on an independent path.

It either lost or never acquired the other features of its family -- the over-sized "man-hands", the velvety pelt, and the predilection for subterranean foraging.

The transformation gave us a mole that can't "swim" the soil with the talpid breaststroke, doesn't makes mole-hills, and lacks the napless and velvety mole pelt that once adorned Yankee waistcoats.

Shrew-moles walk on the soles of their forefeet, which is impossible for moles to do, and sometimes they walk on their knuckles, like anteaters, armadillos, and gorillas.

What's more, they can stand bi-pedally like a squirrel and climb into low vegetation, which moles can't do.

And then there's the mole-snout.

Shrew-moles perfected it as a somewhat flattened and flexible walking stick with lateralized nostrils.

The foraging shrew-mole taps its nose center, right, and left with each step.

Dalquest and Orcutt, who studied the species nearly 80 years ago reported that the snout "may be thrown high in the air, twisted to one side or the other, rapped on the ground, or hooked under the body."

When it sniffs out a sowbug or earthworm, the shrew-mole thrusts its nose, and hooks and pulls out the prize like little Jack Horner.

The photo below seems to show it nose-plucking sunflower seeds the same way.

A shrew-mole roots for sun-flower seeds in redwood duff.

Most of the photos were false-triggers probably caused by something scurrying through the frame before the shutter fired.

I was hurriedly clicking through these "blank" images when the time-lapse effect revealed a Brownian swarm of pale larval millipedes.

These I assumed were instars of the yellow-spotted millipedes (Harpaphe haydeniana) so common in the area.

An immature miilipede or instar, presumably
the yellow-spotted millipede. 

In one frame a shrew rooted sunflower seeds in a flock of 12 baby millipedes.

In another frame two dozen baby millipedes grazed together peacefully.


It was like a miniature Serengeti with hunters and hunted drifting on and off the stage of life.


Wow, I had made a discovery!

"No wonder there are shrews here, there's an endless supply of tender nourishing millipedes."  

Or so I thought.

Yes, they looked like "easy pickins", but were they shrew fodder?

It was time to search the literature.

I found that Robert Stebbins, the late and great herpetologist once dropped a couple of millipedes (Tylobolus stebbinsi) into a jar containing a western skink, and despite the lizard's predatory restraint it was dead in 3 hours.  

Millipedes look meek, but their "repugnatorial glands" are highly effective weapons of chemical warfare.

Their many-segmented-bodies are equipped with stink glands, which can be selectively activated to release any number of noxious gases depending on the species.

The gas has a distracting effect on predators such as mice and birds, which immediately lose interest in their meal, blink their eyes, plow their faces in the soil, and go into fits of self grooming.

Yellow-spotted millipedes produce hydrogen cyanide which in low concentrations has a pleasant almondy-smell  (and gives me an appetite for Danish pastry).

According to Bug World the species is toxic to shrews.

Are immature stages also toxic, or as toxic as adults?

Millipede specialist Bill Shear informed me that baby millipedes can produce toxins as early as the 3rd instar.

At this stage of development they are probably too small to interest shrews or shrew-moles as food.

This probably explains why the myriad baby millipedes safely grazed while the shrews ate sunflower seeds nearby.


"When frightened, Neurotrichus makes an unbelievably swift, scuttling dash for cover."
(Dalquest and Orcutt, 1944, p. 391)


References:


Dalquest, W. AND D.R. Orcutt. 1942. The biology of the least shrew mole, Neurotrichus gibbsii minor.   American Midland Naturalist, 27:387-401.

Eisner, T. and J. Meinwald. 1966. Defensive Secretions of Arthropods. Science, 153, No. Shear, W. 3742:1341-1350


Shear, W. A. 2015. The chemical defenses of millipedes (diplopoda): Biochemistry, physiology and ecology. Biochemical Systematics and Ecology, 61:78-117.


Stebbins, R.C. 1944. Lizards killed by a millipede. American Midland Naturalist. 32 (3):777-778.


Acknowledgements:

Many thanks for Dave Rentz, Petra Sierwald, and Bob Mesibov for leading me to Bill Shear, who kindly shared with me his excellent and fascinating review of millipede chemical defenses.  

Thursday, June 25, 2015

A white-breasted nuthatchery



I hope the incubating nuthatch in this box was satisfied with its mates' choices of carry-out.  

During incubation he served his lady a lot of legless carpenter ants, and she accepted them eagerly. 



Occasionally he served her a red ant, but . . .




the mainstay was caterpillars (which Mr Smiley identified as those of noctuid moths).  He also delivered shelled sunflower seeds from our bird feeder.  

He was a bit of a show-off. His acrobatics were eyecatching, . . . 



  but he didn't hang around after deliveries. 




I was puzzled by the occasional delivery of squirrel fur, a feather, and perhaps paper mache from wasps' nests. 

At these times he was also photographed peering into a gap in the box. 

The old nest box was coming loose at the backboard, and I gather the materials were intended for nest maintenance -- an attempt to chink the gap with fuzzy bird oakum.  




Finally the hen appeared with a fecal sac, and I knew the eggs had hatched. 

Apparently she made hasty exits, because the camera trap never caught this action again. 




When the chicks hatched, spiders and small beetles were added to the mainstay of caterpillars . . . 











and then moths replaced caterpillars.














The camera snapped one youngster the day before the family suddenly disappeared.




Except for yellow rubber-band lips and short tail, junior looked just like its parents.




The little imp also looked vulnerable, especially clinging to the box.
















The next morning . . . (insert a heart-rending "oh no" here) . . . my camera caught several images of a Steller jay on top of the nest box.



I immediately checked it out with a flashlight.

The box was empty. There were no nuthatches at the feeder either.

I started to think the worse. Did the jay eat the fledglings? (Of course it did, you damn fool. Wasn't it just there, looking for more?)

It would have been so easy to nail the little buggers, and that's probably what happened. (Hey, you're a biologist. This is how it works.)

Two weeks later four nuthatches showed up at the feeder.

If the jay dined on tender nuthatch, it didn't get all of them.

Thursday, June 18, 2015

Scree in Winter

Deadman Lake and its scree, on the north facing slope of Rt 49 (Google earth image)

You are looking at Deadman Lake at 6675 feet, and its ancient field of scree that spills downhill nearly 700 feet.

A camera set in deep boulder-scree
We set camera traps on Deadman's scree slope last November.

It's a strange place.

In summer you can slow-fry eggs on the sun-baked boulders, while cool drafts and the babble of moving water rise from the depths. 

In winter it's a wasteland of ice and snow,  

We've camera trapped Deadman in summer and fall, when little chief hares or pikas raise their squeaky alarm.

Scree isn't plant friendly, and you wouldn't expect many small mammals other than pika to live there.

But we've photographed wood rats, deer mice, chickarees, chipmunks, and golden-mantled ground squirrels far from the more vegetated edges.

The presence of those critters convinced me that talus must be a winter paradise for weasels.

It offers ever-present protection from the elements, thousands of recesses to escape from hungry raptors, and a steady supply of food.

Normally Deadman starts to look glacial in mid October, but winter was late last year.

We managed to get our act together in early November, and set our camera traps in shirt sleeves on a fine Indian summer day.

Six months later we were casting about and scratching our heads looking for our cameras.

I was the one who couldn't find his cameras, and even with the GPS telling me I was there I still had to peer into deep recesses to find two of them.

The camera batteries had died months earlier in most, but two of my cameras set a new record of 6 months -- they were still running on external D-cells.

We didn't have much to show for our patience, and we didn't get a single picture of a white weasel.

But a bobcat made several appearances at the first cam I set at the foot of the scree.



Full frame of scree visitor


The space was too small for a full body shot, but the cat showed us both working ends. 


Another revealing view.