The Bewitching Fog shrew

Getting a half-way decent shrew picture is an occasion for jubilation and a bottle of beer.

And this, kind readers, appears to be a Fog shrew (Sorex sonomae) -- two-toned and in the middle of its fall molt.  From the wilds of Marin County,

Bewitching, wouldn't you say?

Did I hear someone say BS?

Okay, I don't know it's a Fog shrew for certain, because shrews are buggers to identify and it helps if you're nearsighted.

You really need to get their skulls out of their heads, or at least give them a microscopic dental exam.

But among Western North American shrews the Fog shrew is a biggie -- up to 150 mm in total length, and if you know the size of big leaf maple leaves, like the one next to this shrew, then you know this is a big shrew.

The Fog shrew also has a unicolored tail, while most western shrews have bicolored tails with much darker dorsal surfaces.

An identity crisis has dogged this shrew for many years.

Hartley H.T. Jackson, who by the way wrote his first scientific paper at the tender age of 15 when most boys are doing other things,  called it the Pacific shrew (Sorex pacificus).

But not for its peaceful disposition. It's at home in the cool coastal forests from northern Oregon to Marin County in California.

Three and a half decades later a young Jim Findley demoted it from full species to a subspecies of the puny but more widespread Wandering shrew (Sorex vagrans sonomae). It was the macro-shrew at the end of the Rassenkreis.

The late medical doctor-mammalogist Murray Johnson and B.T. Ostenson took issue with that decision, but the demotion stuck for forty-five years.

Then Leslie Carraway, a high-powered lady from Texas with an obsession for shrews concluded that it was not the wandering vagrans.

She elevated its rank to the foggy sonomae, and for the time being her word is final.

Such is taxonomy.

Christian and I set the camera close to the ground at a small spring that debouches from a patch of ferns.

We were lucky.

If you want to camera trap shrews you really have to enter the netherworld of duff and detritus.

You need a tiny camera trap with a short focal length.

You need a lure that smells like slugs, centipedes and worms.

It was just good fortune. The Fog shrew ventured out of the duff.

References

Carraway, Leslie N. 1985. Sorex pacificus. Mammalian Species, No. 231, pp. 1-5.

Verts, B.J. and L.N. Carraway. 1998. Land Mammals of Oregon. University of California Press, Berkeley

Cautious coyote

August 21, 7:21 PM, Set 320

"Whenever the pressure of our complex city life thins my blood and numbs my brain, I seek relief in the trail; and when I hear the coyote wailing to the yellow dawn, my cares fall from me - I am happy."

Hamlin Garland

Couldn't agree more.

Four visits -- four views

August 17, 1:27 AM -- Day 6

Back from a few cool days on the Chimineas, the camera trapping wonderland, but I am running a bit low on material.

The previous trip was a hard act to follow, and this time there were no surprises -- only the usual suspects

So we're serving up a few shots of bobcat(s) from a 38-day set made by the team in mid-August.

This is on top of the rock pile where we photographed a bobcat last winter.

The bait is secreted in the crack between the two rocks at the right.

None of the pictures was cropped, so you can see how the cat(s) moved around on the 4 occasions it visited the set.

August 22, 1:33 AM -- Day 6

Yes, the first two pictures of the same cat.

Aug 22, 9:39 PM -- Day 11

And it looks like she visited again 5 days later.

August 27, 10:28 PM --  Day 36

Not sure it was the same cat on the last visit, because it's behind the rock on the left.

It was upstaged by a moth impersonating a bat with landing gear deployed.

Barny moves on

It was twenty-five days into Barny's nocturnal escapades when the she-pig came back.

She downed the camera trap with porcine recklessness, but paid it no further heed.

It lay on its back, three round eyes to blazing sun and starry night.

Our good fortune with Barney though wasn't yet over.

Two nights later --  at 9:41 to be exact, she appeared out of the darkness like a red-eyed Valkyrie, and the camera recorded her passing.

It was the only photo of her that night. If she touched down in the swale she kept her distance.

She made 8 more visits during the next 11 days, but we don't know if she played with the seed heads.

On each visit however she peered at the waylaid camera, sometimes looking down through her toes  . . . and sometimes leaning in from the side.

Then she disappeared into the night.

We'll be back at the grassy swale looking for Barny next year. 

Barny's adventures, continued

It seemed that Barny was a-huntin'.

Like a Peeping Tom she spent a lot of time peering -- peering into the trampled grass.

A wee sleekit beastie' was probably crepitating therein, and Barny, it seemed, was channeling the sound with her facial disk.

That's how I read the photos, but I needed confirmation.

Hans Peeter's Field Guide to Owls of California and the West made no mention of barn owls foraging on the ground . . . had we made a discovery?

I sent Peeters a message and he answered . . .

I myself had never heard of Barn Owls foraging on foot, although it wouldn't totally surprise me. This species, however, is so highly aurally inclined in its hunting that infantry-style foraging would be a surprise. Do you have videos? All owls, having pounced on prey and missed, do a certain amount of walking about and weaving their heads from side to side to obtain auditory clues, and all seem to be far-sighted and therefore back up from the point of impact and try to locate the prey by sight. 

I quickly googled up a minor paper at http://www.fosbirds.org/FFN/PDFs/FFNv26n3p91-93McMillian.pdf which seems to present pretty good evidence of foot hunting by Great Horned Owls, and it mentions other references (though I couldn't locate any discussion of the phenomenon in Johnsgard, which the author mentions. I am also not entirely convinced that his owls actually ate the tern eggs; eggs of ducks and coots not infrequently turn up undamaged in GHO nests, having slipped out of the bodies of prey brought there. Such eggs are not eaten and become part of the nest detritus. 

At any rate, if you can provide more detail or video of the foraging on foot that you have seen, I would very much like to see it. 

Then came another message . . . 

While ruminating about your pedestrian foragers, I remembered that I have seen Burrowing Owls hunt crickets on foot during the day; of course that species is highly visually oriented and more or less cathemeral, so that's no great surprise. The Eurasian Tawny Owl, however, is completely nocturnal but also forages for earthworms on foot sometimes (I've seen Red-shouldered Hawks do so in the daytime, rather surprisingly, since it's such insubstantial prey for such a large raptor).

The codger was highly gruntled with the finding, and began daydreaming about ways of getting the evidence in video.

The problem was time. The days were getting shorter and we hadn't even scheduled the next trip to Chimineas.

Meanwhile, Craig succumbed to curiosity -- he hauled his live traps to Barny's stomping ground, and though he caught deer mice and pocket mice in the neighborhood, harvest mice were the only mice in the swale.

Once again I poured over the photos searching for some hint of the elusive quarry . . . some telling crumb of evidence in the corner of Barny's beak, like the spurred femora of a Jerusalem cricket.

At last I found some frames of suspicious activity -- Oh my God! -- frames of Barny holding something fuzzy in her beak.

I dragged the jpeg into Photoshop and zoomed in.

The victim was no wee mousie -- but the seed head of annual rabbitsfoot grass, Polypogon monspieliensis.  

There was actually a sequence -- Now Barny was gripping a seed head in her talons.

Then she was either eating it or tearing it apart!

Was Barny pouncing on imaginary mice in the form of grass seeds?

And sampling them for texture and digestabilty?

The swale seemed a strange and risky place for Barny to hone her hunting skills, if that is what she was doing. 


A predator could explode out of the grass and catch the owl in the midst of her baffling game.


All good things do come to an end, don't they?

Barny's cakewalk in the swale

A marshy stretch on Barrett Creek . . . . the barn owls' stomping ground. 

Craig thought Barrett Creek was good for another camera trap set.

Though all but dry in early August, a lush swale marked its meandering course, and here and there the ground was even soggy.

It was a little oasis of greenery, but if any critter smelled water there it would have to dig for it.

I predicted that the swale would be a haven for meadow mice and their predators, thinking we might at last get a picture of our long-tailed weasel.

So we trampled down a couple square yards of grass and concealed the camera at the edge of the clearing -- set 388.

Six weeks later the team viewed the photos and found that the camera had taken over 750 photos of pigs, black-tailed deer, and cotton-tails, and not a single carnivore.

But barn owls were the big surprise.

There were 357 photos of them.

Barn owls all look the same to me, but I suspect it was one or two birds that visited 32 times on 26 nights, and almost always before midnight.

On only two successive nights however did a pair of owls show up in the same picture, and in three frames they curtsied.  

I need an experienced owler to tell me if this was courtship, threat, or begging for food.

Or maybe the introduction to a cakewalk?

Who knows?

The bigger question though is what exactly were they doing there?

How to solve the one-way road dilemma?

Oct. 8, 2010, 9:50 PM

Oct. 14, 2010, 1:42 AM

Oct. 18, 2010, 8:44 PM

I think it's the same cat, and it's ignoring the sign.

It seems to think it's on a one-way road.

How to get a head-on picture of this trespasser?

A) Turn the camera around.

B) Change the Posted Sign so it faces the opposite direction.

C) Urinate across the road to turn the cat back.

D) Move the road apples closer to the camera.