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, December 31, 2006

A year of camera trappin'

Luck--or being at the right place at the right time accounts for some success, but not all success. I wanted to measure my camera trapping success under different conditions. After all, who wants to trudge through cold rain and mud only to find 20 exposures without critters. It’s like the Earth Goddess forgot to put your packages under Nature’s Christmas tree. So it's time to summarize the many days I squandered in the woods (when I could have been doing something useful, like raking leaves or cleaning gutters).

On a spreadsheet I recorded:
a) the amount of time the cam was available to photograph wildlife,
b) the location (a trail in the woods, a clearing, a water hole), and
c) the attractants used (bait, scent, scat, etc.), if any.

The cameras captured images of 14 species of mammals and one mammal I couldn't identify. This is a highly biased selection, because once an animal gave me a lead, I usually targeted the critter for pictures. Some species were easy to photograph. Foxes, skunks and rodents were attracted to baits, while ringtails and bobcats were not as vulnerable. Deer commonly use trails through the woods, but I wasn't after deer. I find it a little odd that there weren't more pictures of raccoons. And how come I'm not getting coyotes? The neighbors say 10 years ago they howled all night. Have they all been trapped out? The most unexpected picture was the shrew. Pure chance! The biggest thrill was the ringtail and puma, and the bear was gratifying after the ordeal it put me through.

Apologies to my ornithological friends. I never tried to photograph birds, but I got their pictures anyway. Jays, ravens and titmice were all attracted to sunflower seeds, but the hermit thrushes were a surprise. They were the most common visitor to one small waterhole deep in a ravine, where they seemed to be feeding on aquatic insects. (If there was a way to get closeups with these cameras I could get interested in taking pics of dicky birds).

I defined success rate as # of photos with animals divided by the total # of photos.

Total # of camera-trap-days: 755
Total # pictures: 2085
Total # animal pictures: 1060
Overall success rate: 50%
Range of success rate:
by camera: 20% to 90%
24 hr vs night: 33% vs 74%
unbaited sets: 22% (24 hr), 73% (night)
meat sets: 44% (24 hr), 79% (night)
waterhole sets: 72% (24 hr)
seed bait sets: 38% (24 hr), 74% (night)


NUMBER OF CAMERA TRAP DAYS: From Nov 13, 2005 to year's end 2006 I had anywhere from 1 to 5 camera traps in operation. I used 5 cameras: a Cuddaback, an Olympus 390, two Olympus 360Ls, one Sony P32, and 5 Sony s600s. (The Cuddaback is commercial, the others are "homebrews", hacked by the codger himself). I didn't run traps all year long. So the sample size could have been larger.

CAMERA DIFFERENCES: There were differences between cameras in the time required to fire up when the PIR first detects "moving heat. I didn’t compare cams because the sample size was small in some cameras, and there were too many uncontrolled variables. When I adopted the Sony s600, I stopped using the others. The s600 doesn’t fire up as fast as the p32 and P41, but the 6 MP pictures are a compensation. The biggest improvement for me was the production of the new Trail Mode chip for the Pixcontroller board. It allows rapid succession of exposures. Once activated the camera remains on for another 30 seconds after each PIR event. This allows the camera to rapidly fire like a paparrazo. That’s exactly what I want—a camera that takes as many pictures possible as long as the animal is present. "I don't want no schtinkin' minimal interval of 1 minute between pictures."

24 HR VERSUS NIGHT MODE: At many camera sets where the sun reached the ground the sensor detected warm moving air and triggered the camera. False triggering explains the different success rates of the 24 hr and night modes. I got fewer false triggers in night mode.

BAITED VERSUS UNBAITED CAMERAS: Bait almost always increased the number of animal pictures (success rate). Presence or absence of bait seems to have made little or no difference at night. This seems odd, and may be an artifact. I need to look into this next year.

CONCLUSION: My highest success rates came when I used bait, and set the mode for nocturnal shots only. Isolated waterholes attracted birds and mammals just as well as bait does, and 24 hours a day at that, though bears never bathed or drank at night. But I failed to photograph a number of mammals that I know are here. I'll sample more habitats this coming year, and experiment with different kinds of lures. My colleagues and I are also talking about teaming up to do an experiment on the effectiveness of different attractants.

Friday, December 29, 2006

Stumped by birds

I was stumped.

Ever since ringtail exposed herself, I've been angling for more pictures of that trim body, and especially a few shots showing the full length of that gloriously fluffy banded tail. Getting more pictures of that little charmer meant I had to outsmart the fox. Ringtail had stayed away ever since Br'er fox showed up. He had become a camera hog. I mean, 70 pictures a night is a bit much.

My ploy was to place the bait out of the fox's reach, because ringtails are good climbers. As you have seen ("Br'er fox can climb"), a four foot snag was no contest for the fox. So the next night I draped the goodies--chicken neck and liver--on the log's tallest snag, thinking that six feet might be out of reach. I staked the cam 6 feet away and set it for a vertical frame or "portrait".

The next day the bait was gone and I chuckled "Got it"! I switched the camera to VIEW, and got the blue screen with that disappointing message: "No file in the folder"--technotalk for "no pictures". Time for analysis. The sensor must be out of kilter, I thought, and it must be related to the camera's vertical position. Ringtail could also be eluding the sensor by climbing up the back of the snag. I turned on the control board, did the "walk test", and re-adjusted the camera's position.

The next day--same message, no pics. Then it dawned on me. The bait thieves are coming during the day, dummy! I changed the dip switch from "Night" to "24 hour" pictures.

On the third day, the bait was gone, but the cam had captured the images of thieving ravens. I had been stumped by birds.

There were three ravens sat in a tree
Down a down hey down hey down.

They were as black as black can be
With a down

And one of them said to his mate
O where shall we our breakfast take
with a down derry derry derry down down

O down in yonder bramble wood
Down a down hey down hey down

There is a man who's done us good
with a down

Each day he ambles down the trail
his mind is gone, but he's not yet frail
with a down derry derry derry down down

For reasons only known to him
Down a down hey down hey down

He dangles chicken on the limb
with a down

It's such good luck that such lost souls
stuff well-cured mice in wooden holes
with a down derry derry derry down down

He must have gone to graduate school
Down a down hey down hey down

Its only there they make such fools
With a down

Thank God he ignored the honeydo list
Or this fine meal we would have missed

[Okay, okay--I hacked it badly--but it's easier to mangle an old ballad than write it from scratch.]

Wednesday, December 27, 2006

The owl and the pussy cats

I set the cam at this mossy rock at a creek crossing on Dec. 6. Nothing happened there at all until Dec 20 when the gray fox showed up for two pics. The pumas came on Dec 22nd and 23rd. I got two pictures of them each day. These are the same two cats I photographed 18 days earlier sitting on the road below our house (see "No poodles tonight"). You can still see vague spots from the cub's neonatal coat, and from the size of its feet I would guess that its a male.

But let's not ignore the screech owl (or is it saw whet owl), who made its appearance the day after Christmas. When our windows are open in the summer we listen to this fellow's serenade, but so far he hasn't moved in to either of two nest boxes I hung in the woods.

Sasquatch raids the garbage

Sasquatch got into the garbage last night. In our neighborhood, Waste Management collects the garbage Wednesday morning; so everyone drags their cans to the road the night before. Sasquatch seems to know the schedule. She (and maybe other bears) have been doing the garbage run here for several years. Even down in Butte Creek canyon you can find bear scat with black plastic in it.

Neighbor Richard, who can see the garbage cans from his house, called this morning and reported that his garbage can was upright, my can was knocked over but the garbage was untouched, and neighbor Shannon's garbage was all over the place.

Richard's forensic interpretation is that Shannon's garbage was the first target. It probably smelled the best, and Sasquatch obviously took her time dining there. After that, she tipped Richard's can and triggered the "screaming canary" alarm--that's the one dollar security alarm that he fastened to the lid of his can (see October's post "Coexistence at last"). When the bear stumbled backwards, he surmises, it knocked over my can. Presumably, it was so alarmed by the ear-piercing "canary" that it went away. [Two of the neighbor's dogs were eating scraps when Richard visited the scene of the crime. He said they cowered and tucked their tails between their legs when he lifted his garbage can lid and the canary started to scream.

I checked the camera traps by my house, but there were no bear pictures. Sasquatch must have approached the neighborhood by a different route.

Tuesday, December 26, 2006

Jackalope shed its horns

The jackalope rut must be over, because this buck is no longer wearing his headgear. He has that alarmed and bug-eyed look that many bucks get when they lose these weapons and status symbols that are so important for reproductive success in jackalope society.

Sunday, December 24, 2006

Familiarity cures camera shyness

What is it and what does it mean? It's a closeup of the ear of a gray fox, and it means the fox isn't afraid of the camera. But it wasn't always that way.

I can't prove it, but I am pretty sure that most of my several hundred gray fox pictures are of the same animal. My first encounters with it were fruitless. The animal took the bait, but evaded the camera's shutter.

Then I discovered that the little red light on the passive infra-red sensor was scaring the animal away. I deactivated the light and started to get pictures. For a while the fox was leary, and the pictures were nothing to write home about.

In a few weeks it became bold enough to scent mark shamelessly in front of the camera (see "A flawed photo essay..." Jan 2005). But many pictures were of the fox with closed eyes. It seemed to have an uncanny ability to anticipate the flash.

Now, many months later, it is actually curious about "the thing that flashes". This week was the first time I photographed the fox sticking its face in the camera and sniffing it. On the night of Dec. 20, 6 out of 59 photos of the fox were point blank face flashes. Of course Br'er fox kept his eyes shut.

Thursday, December 21, 2006

Br'er fox can climb

I put the bait on top of the snag, and it wasn't much of a challenge. Gray foxes are known to be good climbers, and there's even a report of one climbing 18 m into a tree. But their descent is not as surefooted as a squirrel or ringtail, because they can't rotate the ankles of their hindlegs and hang on by the claws.

Tuesday, December 19, 2006

Br'er fox can't find mousie

Br'er fox triggered 70 exposures last night, and not a single one was blank. Here he is looking for the elusive mousie which is in the hole on the side of the log. He finally found it, but he hung around afterwards looking for more goodies.

I'll have to try some new camera angles now that I know how he moves around on the log. Wonder if he can get to the top of that snag?

Sunday, December 17, 2006

Ringtail exposes herself

The secret to getting these pictures of a ringtail might have been a crab dinner last week. The next morning Shirlee woke up saying, "Do I smell garbage?" Half asleep and not smelling anything, I assumed
the question was a gentle message. "No dear, that must be me."

When I started to brew the coffee I knew what she was talking about. A powerful stench was coming from under the sink. I moved the reeking crab shells to the garage, where I was doing a project, and the stink increased even more during the day. Something had to be done. We couldn’t wait until garbage collection day. That’s when I got the idea. I crushed the shells in a plastic bag, transforming them into a gooey paste. Crab potion #9.

Late that afternoon I spooned the potion into some holes in an old cedar log where one of the cameras is set. Up to now the only visitors to this log had been a spotted skunk and mice, and I expected more pictures of the same. I was mighty pleased 24 hours later when I found this charming critter in 8 out of nine images!

I cropped the first shot, but the second one shows the full frame as she sniffs the tangy potion in the hole. After that she ate a bait mouse, but the camera was a little too close, and her head was partly out of the frame. Dang!

By the way, the ringtail plucked the mouse. There was a little pile of mouse fur at the foot of the log. As far as I know, that's a trait shared by cats, but not members of the raccoon family. No evidence that she sampled the potion, but it was still

Friday, December 8, 2006

Love is in the air?

The striped skunk mates in the winter. In January and February, the males ramble about looking for mates and often meet with misadventure when they cross busy highways. I have never gotten a picture of a family group or a pair of striped skunks, so this picture is a little unusual. There are two possibilities. A couple of skunks just happened to meet, or we are seeing a prelude to courtship. I favor the latter. It looks to me like the skunk in the foreground (a female?) is looking over its shoulder at the pursuer (an amorous male?).

More recently researchers have shown that stripped skunks den together in the winter--one male with a group of females.

Monday, December 4, 2006

No poodles tonight

A mountain lion and her half grown cub visited the suburbs of rural Magalia last night. The two cats seen here must have reached the ridge by some other route, or maybe they just skirted the camera trap's sensor. Anyway, it seems they gave up on sububan hunting early in the evening. The picture was taken at 12:24AM as they passed our house--heading back down into Butte Creek Canyon. . .which leads me to conclude that there were no poodles or other pets to be found for dinner. Mom sat down to lick her breast as she waited for her youngster--8 seconds later junior joined her and they resumed their stroll down the road.