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.

Friday, February 29, 2008

Owl box finished

The weather was ideal for hanging owl boxes this week. Visibility in the woods is still good -- the gooseberries are just leafing out, but the poison oak thickets are still dormant. Plus, the air is delicately scented with bay flowers.

Maybe it's a little late to hang owl boxes, but it feels good to have finally finished the project. One has a 2.5" hole (to favor saw whet owls), and the other has a 3" hole (for screechers). The latter can accomodate a camera module.

It was easy enough to cut and assemble the owl boxes. I had all materials on hand. (I'm cheap and used recycled redwood and hardware).

The only expense was the galvanized flashing needed for squirrel proofing. You have to cut and apply the flashing, but that's not a problem when your neighbor's mantra is "The guy who dies with the most tools wins". Richard has a sheet metal break and an pneumatic stapler, and that made the job easier.

Covering sacred redwood with flashing seems like a crime, but it's bearable if it defeats homesteading by 'wathcally sqouyals'.

Of course, the flashing makes your box look as ugly as a hemorrhoid. It glares like a beacon in the afternoon sun. And who knows -- maybe it reflects wave lengths that attract bees looking for prospective hives. So you have to paint the metal (and treat it with vinegar so the paint sticks).

And then there are the finishing touches, like the internal owl ladder or perch (see below), drainage holes, and a layer of clean sawdust or wood shavings.

I settled for a small grove of Douglas firs for the screech owl box and pruned a clear flight path to the box. It's about 25 feet up on the NW side.

The branches make it easy to climb up to the box, but I'm thinking I should take the chain saw and cut them off this weekend. A bear could climb the tree with or without branches, but why make it easy?

Thursday, February 28, 2008

Taking the dive

"Whatever this is, it smells veeery interesting."

"And I think I want to blend with its essence. Here it goes."

"I'm taking the dive. Aaaahhhh. . . . jitterbug perfume."

[My apologies, faithful viewers, for the same old same old. You've seen it here before, I know. It's just that smelly substances have this magical effect on foxes and carnivores in general. They simply must 'take the dive'. I'm as much to blame as Br'er fox.]

Wednesday, February 27, 2008

On the prowl

Winter and spring seem to be my mountain lion season. This picture was taken on February 18th at 7:00PM. (The glare is reflection from water on the lens window.)

I presume it was the same cat that passed in the opposite direction 19 hours earlier, and 3 days earlier. That vague image of the cat's derriere is 11 paces away (about 50 ft).

It's probably safe to say it was working the north ravine for deer and jackrabbits. I found mountain lion scat about 100 yards up the trail. (No, it didn't eat a camera trap and pass the AA battery.)

By the way, this deer trail passes within 50 yards of my house.

I expect this cat has moved on by now, but I won't be disappointed if I get more pictures.

Tuesday, February 26, 2008

The cat that won't show its face

A camera trapper's saddest pleasure is getting pictures of a much sought species, but never getting them right.

This is my problem with a local bobcat. I get pictures of it at three different camera sets, but I rarely see its face.

After months of putting scent lures on the patch, I finally got the cat's attention (I'm talking about the picture above). Unlike the cooperative mountain lion at this location, the bobcat played hard to get.

It visited this set only one other time. Though its face was visible in that picture it walked on by so close to the camera that it was overexposed.

Recently I set a camera on a new trail that seemed promising. The cat showed up the first week moving at a good clip, and the camera captured only its backside.

A couple minutes later it retraced it steps, giving another view of its backside and the spots on the back of its ears.

Nearby there's a nice mossy rock, and I was able to lure it there using castoreum. It posed well, but once again it didn't show its face.

I'm still working at it. I just have to find something that occupies the rascal's attention long enough for the camera to fire several shots.

Monday, February 25, 2008

Bird ID quiz

Maybe some birder or owler out there can tell me what this is, or isn't?

You are looking at the full frame, and your eagle eyes, I am certain, have already zeroed in on the round fluffy thing on the branch at the left.

Here it is closer up. The diameter of the tree (a Douglas fir sapling) is about 6 inches at the bird's level.

It seems too big to be a screech owl. What is it?

Sunday, February 24, 2008

Strangers in the night

Action on the skunk singles scene is picking up.

These photos from two cameras were taken an hour and 35 minutes apart on a rainy night. I suspect they are the same two animals, a pair, and that this is not business as usual. As flawed as they are, the pictures tell us that the striped skunk breeding season is underway.

In the eastern US and upper midwest skunks den together in winter. (I am not sure it's the same in mild parts of California.) Researchers most commonly encounter female slumber parties, but single males often join the group (and all male sleeping groups are found more rarely). This is a good arrangement from the standpoint of energy conservation, but not for orgies.

While the sleeping arrangement looks suspiciously like a seraglio, it is not. The male has no command over the ladies, and there is no evidence of the dormitory effect or synchronized estrous cycles in skunks.

When the temperature rises and the wind lets up bedmates forage independently, and as in many other solitary mammals, males pursue carnal knowledge one female at a time.

I have a hunch that these strangers in the night are a'courtin'. If true, he's following her because she is in the proceptive phase of her estrous cycle. This is the short period before estrus when a female's pheromones have a potent come-hither-come-yon effect on males, though they reject amorous advances. It's a common pattern in carnivores.

Several males may be attracted to such females, and a honcho emerges from the competition. The winner takes all when the female comes into heat a short time later, or at least he has the first shot at siring the litter.

The all-too-common indicator of the breeding season are dead skunks in the middle of the road. I used to keep count of dead skunks on route 66 when I drove from Front Royal, Virginia to Washington D.C. for weekly meetings, and a bell-shaped curve tracked the frequency over time rather nicely. Male activity usually picks up in the second week of February, even when the temperature is 10 degrees C, but over the years I often saw dead skunks in January. A second spate of flattened skunks would apppear later in the spring and early summer when youngsters were up and about.

The uniqueness of this American road experience moved Loudon Wainwright to compose "Dead Skunk" in 1972, and for six weeks it was #1 on the charts in Little Rock, Arkansas, where apparently it stirred strong emotions.

A number of my colleagues were quite taken with the song, but I always felt that the lyrics could have encompassed other eternal themes like the rake and rambling boy "looking for love in all the wrong places".

The erotic wanderlust of male skunks has not been adequately investigated. In fact the only paper on the subject was written by herpetologist Carl Ernst whose 10-month-old pet male skunk developed disturbing rutting habits for a period of five weeks. The previously docile animal "nervously prowled about and examined every possible hiding place, sniffing loudly..." Its appetite doubled and it peed a pungent urine indiscriminately, which it also lapped and rolled in.

Rutting behavior is a hypersexual phase in the reproductive cycle of polygynous male ungulates and manifests itself in anorexia, aggressive behavior, frequent urination and scent marking, wallowing and increased activity.

Why it occurs in the striped skunk is another question. Maybe it is related to the observation that litter size and weaning success of captive skunks is greatest in females that breed earlier in the season. Timing of birth is often critical, and early-born skunks have more time to grow under favorable conditions.

If so, Ready-Freddies who play the field early in the season would have a reproductive advantage.


Ernst, C.H. 1965. Rutting activities in a captive skunk. Journal of Mammalogy, 46(4):702-703.

Wade-Smith, J. and B. J. Verts. 1982. Mephitus mephitus. Mammalian Species, No. 173, pp. 1-7

Wade-Smith, J. 1978. Reproduction in captive striped skunks, Mephitus mephitus. American Midland Naturalist, 100:452-455.

Sunquist, M.E. Winter activity of striped skunks (Mephitus mephitus) in east-central Minnesota. American Midland Naturalist, 92:434-446.

Thursday, February 21, 2008

The Soul of the Rhino -- A book review

Many biologists feel that some chapter of their life is worthy of a book, and a few actually take the trouble to write about it.

The Soul of the Rhino is such a book. Hemanta Mishra is a Nepali conservationist, and that's what makes this book special. It's a conservation story from the perspective of a developing country national, albeit western educated. Most books of this genre are written by westerners, who rarely treat us to the kind of cultural perspective found here.

This book is about Mishra's rhinoceros years. If you enjoy reading memoirs that intersect travel, wildlife conservation and cross-cultural phenomena, The Soul of the Rhino is worth your time. If you really dig Nepal and its people, all the more reason to get a copy.

Early on Mishra gives us cultural orientation with a glimpse of his childhood. Since Hemanta's birth was preceded by those of 5 brothers, all of whom died within months of birth, you really can't blame his mother for having her son's nose pierced so he would look like a baby girl. It was her way of fooling the fateful Goddess Yama, and it worked.

Next, Mishra's youth plays out against the medieval backdrop of Kathmandu's shuttered houses, narrow streets and temples. When the Kingdom's doors are thrown open to western tourism and foreign aid in the 1960s, the bored graduate joins a clandestine British film crew that captures forbidden footage of Tibetan Khampas beleaguered by the Red Army. When he returns family and friends save his butt from jail.

Next we pan to the terai, where Mishea learns about rhinos from an unlikely guru, an irreverant Tharu elephant driver named Tapsi. Though a Nepali Prime Minister bashed Tapsi's teeth out with the butt of a rifle during a royal hunt, the punishment failed to staunch his foul-mouthed candor and jungle wisdom that pointed the young Mishra in the direction of rhino conservation. (The surly Tapsi is long gone, but in Chitwan's tea shops you can still hear his name.)

Mishra's early career was in Nepal's national parks, and park work in the developing world is a topic unto itself. He weaves the park thread through the book as a series of linked anecdotes. I appreciated "The Clash of Cultures" in which the late Graeme Caughley, a brilliant population ecologist finally became exasperated with "Nepali time". (All Asia hands know what Anthony Burgess meant when he wrote that "time stands still in the East".)

Then the cultural table is turned. The King sends Mishra off for graduate education in the United Kingdom, and he is forced to deal with the distractions of European "dress code", problematic for a young Hindu used to seeing no more than a woman's ankle. There are also the problems of linguistic nuance. He wants to belly laugh when the emissary from the British Council introduces herself as Mrs Hoare.

Then back to Nepal where he tells us about the status of the world's rhinos, poachers and middlemen, royal hunts, and the capture and taming of greater one-horned Asian rhinos. All of this leads to the realization of Tapsi's sentimental wish -- that Nepal's rhinos recolonize with western terai. Before that can happen, though, Mishra is ordered to participate in the ultimate conflict of interests, to participate in the King's once-in-a-lifetime ritual killing of a rhinoceros followed by puja (worship) in its eviscerated body cavity. To my knowledge this may be the only English language account of the famous Tarpan ceremony. Then follows the capture and translocation of Chitwan's rhinos to Bardia Wildlife Sanctuary.

I've known the author for over 30 years, and can say that he is never one to pull punches, gild the lily, or suffer fools. His scatological references are the real thing. That's how he talks. But his court behavior in the presence of the royal family, which is something else altogether, certainly clued me in on the intricacies of caste and Nepalese tradition.

Many of Mishra's friends and colleagues have their parts in the story, including the late King Birendra and prince (now King) Gyanendra, Sir Edmund Hillary and Margaux Hemingway, Esmond Bradley Martin, the seldom seen expert of wildlife trafficking, philanthropist Ed Bass, John Coapman the fun-loving Texan and founder of the famous Tiger Tops Jungle Lodge, and intrepid biologists like Eric Dinerstein and 'Minnesota Dave Smith' (whose names you have also encountered elsewhere in this blog). For me, reading the book was like a visit with old friends.

The Soul of the Rhino is amusing and tragic, and makes it clear that conservation is as much about managing people as wildlife. Progress is by fits and starts, but setbacks are part of the game. The rhino's future in Nepal is far from certain, but there is hope as long as there are people like Hemanta Mishra.

Click here for an interview with Hemanta Mishra, and here to order your copy.

[Below, pit-training a recently captured male rhino calf; a couple pages from the codger's Nepal fieldnotes back in the 80s]

Monday, February 18, 2008

Toward a philosophy of camera trapping

Correspondent Alistair Fraser, who can boast some fine wildlife images taken with remote cameras, recently questioned the appropriateness of the term camera trap. Thanks, Alistair, for rattling my cage.

I like the term camera trap for purely sentimental reasons. It was the term that was used before "trail cams" and "scouting cams" became a commercial enterprise, and it goes back a hundred years or slightly more. When my interest emerged in this use of cameras in the 1960s, one had to make his or her own, and the contraption was just called a camera trap.

For me the use of remotely triggered cameras is a vicarious reenactment of a frontier livelihood. It requires traipsing about in the woods, observational skills, a knowledge of natural history, and survival skills. You capture images instead of animals.

Making a "set" with a camera (that's trapper jargon) is like making a set with a trap. You place either device in such a way as to maximize your success. A trapper only wants the creature to step on the treadle, and the deed is done. A novice camera trapper may be thrilled with any image of an animal, but that soon wears off and expectations start to change. Then the camera trapper tries to induce the subject to pose well or show some of its natural behavior. This requires experimentation, practice, prediction, and previsualization, as well as a understanding of how the animal might respond to the circumstances contrived. Reading about a species' ecology and behavior can help a lot.

Trappers target specific species. I am not interested in photographing every bird and mammal in the woods, or only those species that happen to use the trail. Usually I am after specific quarry. Recently I've been thinking about aquatic voles and shrews. Now there's a challenge.

Now don't get me wrong. I don't mind the newer terms scouting camera or trail camera. They are all the same thing, remote automatically triggered cameras. For me the terms scouting and trail cameras also conjure romantic images. Trappers like Jim Bridger were also frontier scouts. Game trails are safer and more fun to use than roads and highways.

But to me a trail camera is just a camera on a trail. A scouting camera on the other hand implies the exploratory use of a remote camera. A camera trap implies a bag of tricks, including the use of smelly substances and roadkill. These distinctions are more about my own philosophy of using remote cameras than semantics.

In my view, those who want superb wildlife images should sit in a blind and control the shutter themselves. Camera trappers will never (or hardly ever) be able to compete with those guys for imagery. (Maybe that's why I just bought a 10MP digital cam with two long lenses.)

Camera trapping is about a lot more than wildlife photography. It offers a certain abstract element that is missing from sitting in a blind with a 500 mm lens.

There's a curiously intimate spatial relationship in camera trapping, because trapper and animal tread the same ground and the camera set is the nexus of interaction.

Part of it is the inherent handicap of leaving so much to chance. You choose a place to leave a camera in the woods, try to create favorable circumstances, and wait for species x to appear.

There's the everpresent danger of losing your equipment to man or bear.

There's the temptation to take a chance, to leave your camera floating on a small raft in a lake, or hidden in a culvert.

There's an element of serendipity when your camera photographs the unexpected, like a clapper rail, shrew, or red salamander.

There are the disappointments and rewards of experimentation.

And there's the thrill of clicking through the images in the field and finding that your set actually did what you had predicted. Huzzzaaaahhhh!

Then you march home and a familiar voice asks that nagging question, "Okay, smartass, you did it once, but can you do it again".

So camera trapping is a harmless way to explore nature, practice woodcraft, reenact a frontier experience, and learn about wildlife. Oh yes, it's also a way to take pictures of wildlife.

I would say it's also a way to enjoy my second childhood, but the family informs me that my first childhood never ended.

Saturday, February 9, 2008

On making bear guards for camera traps

Our first bear guard design. When Bruin paws the hinged treadle the canary (a $1 security alarm) screams. The terrified and paw-pricked bear never touches another camera trap. Well, that's the theory, anyway.

I finally repaired the camera trashed by the bear. I dried it above the wood stove for a few days, and last weekend I resoldered the torn wires. When I turned it on for the walk test the controller and camera communicated like a charm.

I'm a little smarter now and not taking chances. Many camera trappers have no problems with bears at all, but I am not one of them. Now I only put cameras in the woods that are equipped with homemade bear guards. I have more camera traps than bear guards, however, so it was time to make some more.

I don't use junction boxes or spiked collars for camera traps any longer. Though functional, this set up was too much work to get to the camera.

Neighbor Richard and I have come up with several designs for bear guards, and all of them work. Any spiked metal frame attached to the camera case deters curious bears, but it took several designs to arrive at the quick-set bear guards seen below. If bruin used only his claws he might be able to disarm a camera case of its bear guard, but bears are ham-handed and lose interest as soon as they get pricked.

Richard improved the bear guard design with the addition of angled clamps which make it very easy to attach and remove the guard from Pelican cases. The guard is made of 3/4 x 1/8 inch angle iron. The clamps are excellent fasteners, but you have to cut off the strap slot on the top of the Pelican case. You can find pdf instructions for building it here (registration is free).

The fixed clamp of the bear guard grips the ridge on top of the Pelican case. The adjustable clamp uses a wing nut on a 1/4" threaded rod to grip the ridge on the bottom of the case.

Richard suggested making a more light weight version of the bear guard using 1/8 x 3/4 inch angle aluminum, instead of angle iron. It differs in a few details from the angle iron version described in the pdf. The joints are mitered rather than lapped, and the spikes are made of galvanized nails glued in place with J-B Weld. The iron version used sheet metal screws as spikes (which do not have to be glued--much easier to make).

To cut the aluminum accurately I made a cutting jig for the table saw (top photo, below). After drilling holes for the nails, the 4 pieces of the frame were clamped for welding (middle photo, below). Then the nails were glued in place and allowed to cure for 24 hours (bottom photo, below).

Excess J-B Weld was ground off with a Dremel tool, and the inner surface of the frame was coated with soft polyurethane to minimize scratching the Pelican case. Three pop rivets hold the top clamp in place, and the 1/4" x 20 nut for the bottom clamp is threaded and glued in place.

The cost of materials is about $12 for one, and I bought enough materials to make three. I'm lucky to have a neighbor like Richard who can build practically anything and always offers a helping hand.

I spray painted them this afternoon, and they'll be ready for use tomorrow.

Wednesday, February 6, 2008

Squirrel trials update #2

They're very tricky those squirrels. At the moment they are not cooperating.

The day before yesterday I installed a remote passive infrared (PIR) surveillance alarm in the roof of the owl box under a wire mesh cage. Now the alarm will alert the codger when it is time for squirrel observation.

It works nicely. The infrared detector sends a signal from the box to the receiver in the house which produces a maddening 2-tone alarm. There 's a little red light on the transmitter so you can perform a "walk test".

Yesterday morning the alarm sounded briefly on two occasions between 9:00 and 10:00. Though the box was filled with sunflower seed, the squirrels immediately withdrew. I suspect they heard the alarm through the walls of the house (yes, even I can hear it from out there) or they didn't like the red light blinking on the detector.

Wouldn't it be nice if a blinking red light was all it took to keep squirrels out of owl boxes? Well, I'm not buying it. When they are ready or hungry enough the squirrels will be back.

However, the experiment must continue without delay. Late yesterday I covered the light with electrician's tape, but no squirrels have entered the box today.

I'm going to remove the roof of the box to make the food inside more inviting. We need a population of highly motivated squirrels if we are going to solve this problem.

In the meanwhile we are getting our daily exercise shoveling snow and chopping ice. We've been snowed in for two weeks now, and it's time to buy supplies (like food!).

Monday, February 4, 2008

Squirrel trials update #1

This is an image that strikes terror into the hearts of owl boxers. Imagine how a screech owl feels with this peering into its home.

Yesterday I replaced the front of the experimental owl box with one having a larger (3.5") hole. The 3" hole seemed a little small and I didn't want to invite home renovation by a squirrel.

The box still contained a lot of sunflower seeds but it was filled with icy snow. Since there's precipitation in the forecast I put a lid on it.

This morning, the squirrels didn't show until 11:00, and the following clockwise sequence shows the reaction of one of them to the owl box modification.

This series assured me that there was no need to worry that a lid would discourage them and delay the experiment. Once the hole was located the squirrel wasted no time entering and feeding on and off for a half hour.

It had a room with a view and periodically surveyed its surroundings, as if to say:

"Hey dudes, this is a gnarly place with all kinds of awesome snacks."

Friday, February 1, 2008

The squirrel trials begin

Owlman recently ran a squirrel out of his squirrel-proof screech owl box. When seen on the video monitor the rodent was comfortably ensconced and showing a morbid curiosity in the video camera which happens to be the size of a walnut. This is a scary thing to see on one's owl cam.

I am finishing up a couple of nest boxes for small owls. It's cold working in the garage, but it has been a nice break from home bound routines and shoveling snow. I'm using redwood siding and shelves from the pantry of a 100-year-old house in Santa Cruz. That scaly old paint is rough on the planer blades, but the planed wood is old growth, wonderful to see, touch and smell.

I was California groovin' in the garage -- planing, sawing, thinking about owls, giant redwoods, old saw mills, and the pleasures of free recycled timber, but bothersome visions interrupted my reverie. I saw a squirrel contortionist stretching like a leech to reach the entrance hole . . . a squirrel scaling an impossible expanse of metal flashing like a gecko . . . a squirrel chewing away at the entrance hole, ousting the resident owl, and looking out the misshapen hole with bug-eyed self-satisfaction.

Then the idea came to me. Why not make an experimental owl box and use it to test various squirrel deterrents?

If you have seen the British documentary "Daylight Robbery" you will get my drift. The script was so imaginative, the sound track so cleverly playful, and Dr. Jessica Holm so charming that it inspired a new wave of backyard squirrel research and wholesome campus recreation like squirrel fishing.

Daylight Robbery was actually a celebration of the eastern gray squirrel's problem solving ability, namely in circumventing obstacles and deterrents to the bird feeders. Last year it inspired me to embark on a similar exploration of climbing abilities in a dusky-footed wood rat .

Now I must train the local squirrels to feed in the roofless owl box and test their intrusion skills when the roof is in place. When they're hooked on the early bird special (black sunflower seeds and peanuts) the performance trials will begin. I'll systematically evaluate the deterrent effect of different sized roofs, flashing, hole position, baffles and so on.

Yesterday I set up the roofless owl box and a camera trap, and at 8:00 this morning two small squirrels were on the scene. Neither entered the box, but they perched on it and ate the seeds I left on the edges.

I didn't bother to check the camera for pictures of the first visit, but rest assured it's ready for tomorrow.

Camera trapping workshop query

Here's a query from Alistair Fraser in British Columbia about the camera trapping workshop, which he kindly allowed me to reproduce. My response follows. Be sure to check out his website links -- the photos and captioning are outstanding.

Dr. Chris Wemmer


This might be construed as a fan letter---it is, but it is also an appeal.

With a distance of 1700 km, I will not be attending your workshop on camera traps. Sigh, it is one I would attend if circumstances were otherwise.

I have been using a motion-activated camera for a bit under a year now. I discovered your blog last summer through gamecamera-logbook.blogspot.com and now follow both. I look with envy at the images and scour the text for techniques and tips.

Certainly, I have learned a bit on my own merely by using my camera, but there are many techniques you discuss which I wouldn't have had the wit to employ on my own. I particularly enjoy your insightful discussions of natural history---most people offer pictures alone. It is refreshing to have the insights of a scientist.

Among the many images on my hobby Website devoted to Kootenay Lake,


are some from my own motion-activated camera. I have featured some of the better ones on the page,


A rollover of the image presents a larger version and a click takes you to the page upon which the image (and many others) are presented.

A late summer's project, which might amuse you, was to monitor all the visitors to an apple tree,

See http://kootenay-lake.ca/lakeside/appleraiders

Ok, so much for my attempt to feign credentials in this area. Now, what I really want: is it possible to obtain access to your course materials and insights in the absence of attending the course? I (more-or-less) live in the wilderness and so have had to solve problems of nature photography by experiment. Clearly, I seek guidance.


Alistair Fraser
Kootenay Lake, BC

Hi Alistair,

Thanks a lot for the note, and the links to your webpages. They are professionally done, well written,and the photos are excellent!

Are you sure you need help camera trapping? I'd say you have some first class pictures, and you are doing the right thing -- experimenting. The apple tree idea is the way to go. I found a bee hive in a hollow tree last spring, and got all fired up to set up a camera, then couldn't find it again. (I've got to hunt it down and GPS it now that the trees are bare.) Who knows what visits a bee-tree? Bears for sure, but what else?

I am happy to share information with you. Most of it I will post on the blogsite. There will be a bibliography (not complete by any means, but plenty to read if you can find the journals), and I'll make some pdfs of a few general articles, which I can mail to you. I am about to do a blogpost on bear guards for cams, and that will include a link to a pdf with instructions and materials.

Cliff Wheeler is a great camera trapper, and one of these days I am going to look him up. He's a woodsman and he knows his stuff. Bob Ruse in eastern Washington is another dedicated camera trapper I've met in cyberspace (mainly the Pixcontroller Forum).

I've bookmarked your links, and will follow your work.

Would you mind if I post your letter on the blog? It would give you some additional viewer traffic and serve to advertise the workshop.

best wishes,