Screech Owl update

Last week, after two days of no pictures and nagging fears that a squirrel had dined on screech owl eggs, I was ready to throw in the towel. I decided to wait a few days for my luck to change before going back to pull the camera. When I checked the camera yesterday I found 368 pictures (4 days worth) on the memory stick! Hallelujah!

There were no pictures of nestlings, but all signs indicate that there are young in the nest. Up till now, I never got a photo of two owls, and rarely got pictures of either owl going into the nest cavity. That's no longer the case.



And up till now, I only occasionally found pictures of the owls in the cavity. Now, 40% of the pictures were of the commotion in the nest cavity. There's a lot of flapping and excitement when the food is delivered.



Oddly, there were only three photos of prey: a Jerusalem cricket (or potato bug), and an insect larva.




Where are the mice? The woods are crawling with them. Or do dismembered mice invite blowflies and predators? I plan on keeping a camera on this nest until they fledge. Maybe I'll get a few pictures of the "fluffies".

The submariner's solution

Ever tried to aim a camera trap on the end of a pole at a hole in a tree 12 feet above your head?

What is that nut talking about, you ask?

I'm talking about the trials and tribulations of photographing cavity-nesting birds. You are looking up into the foliage, the sun usually in your eyes, and from one angle the camera looks dead on target. Then you move for a different take, and it looks off target. Photographing the comings and goings of a small bird up close with a camera trap takes the patience of Job. It's a bear adjusting the camera so that the passive infra-red sensor (or PIR) detects the critical area of activity.

If you're not dozing yet, you may be wondering "what's the problem?"

Well, the fresnel lens helps the PIR detect moving heat in a cone-shaped volume that expands with distance from the sensor. At short distances the sensor's area of reception is quite small. I measured it in one of my cameras and found that when my hand was moving only 3 feet away the sensor detected it only within a 5 inch circle.



This means that it takes a lot of trial and error eye-balling to get the PIR 'spot-on' the nest hole.

The other day I bought a cheap laser pointer with the idea of solving the problem. I was going to make a mount for the laser on top of the camera case, so I could aim the PIR quickly and with more certainty.

Then I thought I'd better run the idea by my neighbor Richard.

Richard is a submarine veteran (remember the mechanic Johann in "Das Boot?"), and he's a wizard at all things mechanical.

Well, Richard suggested going with a periscope. At first I was skeptical, but he rummaged around his shop, and in no time assembled a miniature periscope from a piece of square metal tubing, a piece of aluminum bent at 45 degrees, and a small mirror. We velcroed the device to the back of the camera, and aimed the laser up the tube. It worked like a charm.

Next I had to measure the distance between the laser spot and the PIR sensor. To correct for parallax the reflected laser spot should be several inches above the target (depending on the distance between the reflected beam and the center of the PIR). Then you adjust the camera's position on the pole till you get it right. This is pretty easy when using a telescoping fiberglass pole. It's a more tedious process when using square tubing with connecting sleeves.

The next day I hauled the gear down the hill to a cavity located in the end of a broken limb. The periscope indicated the camera was too low. I raised the camera on the pole, but I couldn't tell if I had it right. You see, the trunk wasn't vertical, and after I raised the camera I couldn't see the laser beam from the ground.

The joke was on me. I could only conclude that while technology can solve a lot of problems, nature doesn't always cooperate.

Upscale California housing

Does a deer mouse really need this much space?

When I discovered the den last week, there were auspicious signs that the tenant was larger than a mouse or rat. For one thing, there were no spider webs across the entrance. Something big and furry had been swabbing it out. And there was plenty of bunk space upstairs in the apartment. I had high hopes the occupant would be an opossum or a raccoon (which for some strange reason I rarely photograph here), or maybe a spotted skunk.

I staked it out for four days, but the place was so promising that I paid a visit after the second night.

"Well, I'll be . . ." Something had knocked the camera askew.



And not only that . . . it had bitten off the camera trap's "eyebrow" (a PVC ring hot-glued to the case to protect the lens window from rain). Fortunately, none of the three windows was popped or broken.

The anticipation was killing me. Was I about to find an image of a beady ursine eye peering malevolently into the lens?

I opened the camera, flipped the switch to view mode and clicked through the images . . . deer mouse, deer mouse, blank, deer mouse, blank, deer mouse, deer mouse. . . Get the picture? My spirits were rapidly deflating. Then came the last picture.



This was the only visitor who could fill the den, but Ole Stripey was only passing through and had only paused for a sniff. I had to ask myself--was this skunk my camera's abuser? It seemed so out of character. Surely a skunk wouldn't take on the camera with its teeth. I don't think it could have even reached it.

When I got home I found two sharp indentations, 22.6mm apart (as measured with a caliper) in the base of the PVC ring. Now I ask you, can someone tell me the distance between the canines of a striped skunk? A raccoon? (My skull collection is still in a box somewhere in the garage.)

Anyway, two more days yielded more pictures of (yawn) Peromyscus -- both adults and blue-coated juveniles. The cushy upscale den was only a flop house for deer mice, and I am left with an unsolved puzzle.

Macavity Cat

My first glimpse of Macavity was back in February. I was puttering around outside when I surprised a large tabby cat slipping under the deck. My best falsetto "Here kitty kitty kitty kitty kitty. . ." had no effect. Joy. A new stray was here to prey on birds at the feeder.

Two days later the same cat dashed out of the garage when I surprised it gulping chicken parts consigned to the garbage. I had left the door open for only a few minutes, but Macavity had been watching and made his move. This cat clearly knew far more about us than we knew about him. When I didn't see the cat for a couple of months I concluded it had moved on.

Then one day about three weeks ago I was putzing about the garden, and I kept smelling cat piss. Wherever I went I would suddenly catch a whiff. I was on hands and knees sniffing for a scent post when the redhead casually observed that a cat had urinated on the polar fleece I was wearing.
"Isn't that the polar fleece you left hanging outside for the past few days?" she asked.
(How come women are so perceptive?)
She was correct, of course, and offered to wash it right then and there.
My woodsy codger musk had offended the cat, and my wife advised me not to leave it hanging outside anymore.

A couple weeks passed before our next encounter with Macavity. My wife needed help in the garden. An unknown mammalian herbivore had started to nip buds off the plants. I assured her that the codger could solve the problem, first by identifying the offender, and then by prescribing appropriate measures in behavioral modification. I set a camera trap in the patio.

The only mammal photographed (above) was Macavity on his nightly beat, strolling down the garden path to the back gate, looking confident and in fine fettle. The herbivory ceased and the plants started to recover.

Finally, yesterday I went to the potting shed and noticed a trail of blood and rabbit hair on the ground. I followed the drag mark through the leaves to the water tank. In the narrow space beneath the platform was a dead fully-grown black-tailed jackrabbit.

I put a camera trap under the platform, and this morning found 6 photos. Macavity returned to his prey at 8:12 PM, and apparently fed for 25 minutes. In the last photo at 1:18 AM he had moved the carcass closer to the camera. In the morning there was no trace of it.

The felid body plan is a design for killing warm-blooded vertebrates, and even a house cat has the equipment to take down prey as large as itself.

The snag of fleeting promise

The snag looks promising, wouldnt you agree? As soon as I saw it I thought of small owls or large woodpeckers. So the next day I trundled down the hill with my rucksack filled with sections of a mounting pole, nylon cord, camera, and tool kit. I staked the camera about 6 feet away from the cavity so the sensor would monitor a large area.

It rained that night, but I got one picture. I zoomed in on the LCD, and Whooppeee -- it was a saw-what owl! A new subject to camera trap.



The image was trashed by a drop of water, but I was buoyed by my discovery and moved into action. "Don't bother changing memory sticks", I told myself. "Be patient. In one more day you can savor a whole series of owl shots."

I moved the camera closer to the cavity and messed around for a half hour getting the sensor perfecty aligned. I was feeling the thrill of the camera trapper's chase. Envision the scenario, decide on the optimal angle and distance, double check all the settings, then study the camera's position from all the angles. When I was finished I marched up the hill and felt nice ("like sugar and spice"). The happy prospect of finding a new species does that to you.

The next afternoon I lowered the cam and found . . . WAAHHH! -- 141 pictures! I clicked through a dozen pics of the snag, but the absence of owls didn't worry me. I knew that the nesting screech owls often come and go before the shutter releases--which accounts for empty frames. Then I got home, and found only three images of an animal.



The snag was a high rise for deer mice. Apparently the opening of the nest cavity connected to an "elevator shaft" all the way to the ground. The mice climbed past the nest hole all night long, and triggered the camera on average every minute and 18 seconds.

I consoled myself with the good fortune of getting one picture of a saw-whet owl, and pulled down the camera set. A half hour later I found another promising snag -- a butt-rotted oak with a large den opening at the base. You'll be hearing from me soon.

Return of the beige panther

I moved the camera closer to the boulder last week, and used three lures--the Furfindr, castoreum, and fresh crushed catmint--to attract whatever is out there. I wasn't really expecting another appearance by the beige panther, but the surprise image is what gives camera trapping its thrill.

So today I found 19 photos of the very same cat I posted here a couple weeks ago. The cat with the notched left ear seems to be spending her time in the two ravines on either side of the house.

Study her changing mood. As you can see above, when she arrived at 3:24 AM on April 27th, she was immediately drawn to the scent of the castoreum and catmint.

Next, she settled on the rock and waited for the noisy prey (the Furfindr) to appear. Ahhh, the patience of a cat. The noise-making device, however, was hanging 7 feet above her tail.



The miserable rodent failed to present itself; so she adjusted her position.



Now her head was beneath the periodically sqaulling rodent locked in a section of PVC (just kidding, troops -- it's really a recording device).



She finally accepted defeat, and satisfied herself with a few more snorts of catmint and beaver scent. Then she sat there with the unmistakable look of a forlorn puss.



After twenty six minutes of trying to see, smell, and find the elusive rodent, she parted ways.

Confrontational Skunk

Not much happened on the trap line this past week, so I pulled a few cams and will find new sets soon. This skunk with attitude is the best I can offer. It's a full frame picture, and obviously it reacted to either a previous flash or perhaps the sound of the lens extending. I've seen this stand-off posture in other photos. This should suffice to warn any savvy predator about imminent danger. The next step is an about-face, at which point the stubborn predator is face-to-face with the weapon of musk destruction.