Gray squirrels are the intellectuals of the rodent community. With acute vision and three dimensional mobility, they have developed the memory capacity which allows them to scatter-hoard nuts by burying them for retrieval later.

By comparison the North American red squirrel is so dumb that it stores nuts in hollow trees or in piles under logs, unable to remember where they are unless it runs into the hoard by accident in its daily movements. Red squirrels are prone to lightning-fast, arrow-straight dashes toward a destination. They are also brave to the point of foolishness, apparently believing they can duck a bullet.

I would prefer to talk about the grays, which I quite respect. Grays learn rules of survival and seem to pass them down to subsequent generations. For example, in our woodlot, at the first sign of a human, the squirrels get out of the walnut trees and flee across the forest floor to the other side of the 25 acre plot. This is their response to a pair of determined hunters about ten years ago, and I suppose to the presence of migrating red tailed hawks once the leaves have fallen in fall. But coyotes actively hunt squirrels at this time of year, so there must be some complex calculus of risk/reward going on there somewhere.

Having taken over a large, rambling country house surrounded by walnut trees, I have spent the last ten years establishing the rules for the gray squirrels as they apply to access to the power lines, roof and attic. They seem to learn rules, but are very tenacious once they have established a den in forbidden territory. The only solution at that point is to euthanize every member of that family.

To answer the Quora question, squirrels overthink everything unfamiliar to them. During the Battle of the Attic a few years ago I had live traps baited with black walnuts around the property. One sat on a flat gravel parking area just outside our kitchen. A young male examined the trap and its bait with great care one morning. He kept coming back to it, circling close, but refusing to enter and trip the mechanism. He kept this up so long I shot him.

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All other wild animals make every choice, every movement, in the context of danger checks from their environment. Skunks are utterly self-involved.

When I have had a chance to watch skunks in daylight, each has had a slightly comical detachment reminiscent of the best Bond villains.

Case in point: Our cat lived outside in a heated kennel with a heated water bowl and her food dish inside the small shelter. Something had been booting her out and eating the kibble at night recently, so I had been pressed into service with the Have-A-Heart live trap to remove the miscreant. I suspected a raccoon.

It was 6:30 on a summer evening when I looked out the long laneway leading to the house. Up the road at a slow, undulating gallop came the fattest skunk I had ever seen. This Falstaffian character had a magnificent coat of black and white, and everything was in motion as he approached. It wasn’t that he was nearsighted and didn’t notice me. He just didn’t care. All he could think about was another meal of that glorious cat kibble. The image sticks in my mind of this beautiful, clean, shiny, happy critter, with its mind fixed on one single idea: food.

Of course as he grew closer I grew more and more uncomfortable. Here I was setting up a Have-A-Heart, but it was I who felt trapped. There was no point in attempting to shoo the critter away. He was too dumb to frighten, and of course he had the nuclear option.

Sorry, Cat. I must retreat.

Subterfuge time. I built my skunk-removal strategy around coping with the fallout from the nuclear blast. Obviously the interception point should not be the front verandah of a tall, Victorian brick house in mid-summer. I considered the prevailing wind and land elevation and eventually set the trap behind a low stone wall, to the north and east of the house. The rest of the plan involved a small wagon to transport the toxic trap and its contents after despatch with a .22 round. A raccoon would climb aboard the wagon and into the trap quite willingly, but Falstaff, here, looked as though the height might be a problem for him.

So a day or so later I did the deed, then lifted the trap onto the wagon, dropped the handle over the trailer hitch on my UTV, and towed the reeking problem a half-mile back to the woods, where I unhitched the wagon and got out of there to let the radiation die down.

A couple of days later after a rain I was able to dump Falstaff’s carcass out of the trap for the vultures, but I still had to leave trap and wagon out in the weather in an open area for the forseeable future. Back at the house the ground under the scene of the assassination was soaked with musk. A month later the area still smelled of skunk, but it was away from the house and life went on.

Karma did in the trap and the wagon, though. A neighbour’s tractor ran over the wagon and crushed the trap while mowing the field. I guess I had left my skunk-removal rig out in the air for a little too long.

That’s why skunks seem creepy. They produce in us feelings of admiration undercut by fear, revulsion, and guilt. And the skunks don’t know or care.

Crow Story

December 14, 2018

It was early winter in Eastern Ontario, in a deep gravel pit just north of Seeley’s Bay. I had pulled in with my SUV and trailer to get a load of salted sand. The wind was howling from the south.

As I waited for the loader my attention drifted to a small gaggle of crows fooling around on the edge of a tall bank to the north of me. They were hopping off the edge, only to be blown upward and back by the wind bouncing off the vertical face of the pit.

One slightly smaller crow apparently grew tired of blowing away every time he* tried to soar, picked up an egg-sized piece of gravel in his right claw and hopped off the bank. He suddenly had stability against the wind. He tried again, with a slightly larger stone. He was able to hang motionless in the air. He tried swinging from side to side like a pendulum, and so on. At the time the loader arrived he was well on the way to flying an egg-shaped piece of granite through a loop in the powerful updraft above the wall.

*It is hard to determine gender with a crow, but I have observed a lot of adolescents at play over a 34-year teaching career. This bird was a male.

A Quora reader asked, so I answered:

As a determined planter of black walnut trees, over the last 13 years I’ve had quite an ambivalent relationship to squirrels on my property in Eastern Ontario. First I have to make a distinction between gray squirrels and reds.

The red squirrel provides no benefit to forests, and is as destructive to nut trees as a chipmunk. Both are larder hoarders: chipmunks bury nuts deep in the ground where they cannot germinate, and red squirrels are too stupid to remember where they have put nuts they have harvested, so they pile them in hollow trees or under fence rails where they can encounter them by accident each day.

Then there is the gray squirrel. In my area most grays have black fur due to a mutation in the gene pool. Rarer versions can be gray, blonde, or even white. But it’s not the fur that’s important; it’s the brain. The gray has a formidable intellect.

Grays are scatter-hoarders, storing their food by burying nuts just below the surface and returning to collect them, as needed. Think of the spatial recall necessary to accomplish this when there’s a foot of snow on the ground. Researchers claim the gray uses his sense of smell only in the last inch or two of the search. Of course about nine-tenths of the nuts thus stored are abandoned in a typical year. Forests and lawn plantings result.

So if you have a piece of property which you’d like populated with black walnut and oak, feed the squirrels. Gather a few bushels of black walnut seeds and create feeding stations on the property by placing burlap bags full of nuts in locations sheltered from the rain. There will be no need to open the bags, believe me.

The grays will distribute the nuts over a wide area. On my property I have found black walnut seedlings growing a half-mile from the nearest tree. There was also this one kook who liked to jam walnuts into a fork in the branches of little trees. I have photographed these odd bits of art work all over the 114 acres of the farm. The little guys really get around.

Of course there is a downside to the presence of squirrels when one is attempting to establish a black walnut plantation by planting seeds on a 20′ grid: grays have no respect whatever for rows. They’re also better at planting than I was in my early attempts. They’d dig up the nuts and, more often than not, plant them again six to ten feet from the original hill. Try mowing that. They’d also predate the outer rows of the field, popping out from fence rows for a shady snack, leaving the outer forty feet of the field virtually barren.

Attempts to discipline the squirrel population with my .22 rifle produced varying results. Red squirrels are too stupid to fear a gunshot, so while they’re hard to hit, they can be controlled pretty effectively by hunting. Grays adapt. A case in point: ten years ago a couple of grad students in biology discovered the woodlot and came frequently to help with sugar making and to hunt squirrels.

Clever fellows the biologists were, but individually they had little success against their agile prey, who would simply hide on the other side of the tree branches until their tormentor had given up. Then the guys started hunting in pairs, with an exponential improvement in success rate. The behaviour of the grays mutated in a single generation: even ten years later, when a human enters this particular woodlot on foot, the grays get out of the trees and run Hell-for-leather in a straight line across the ground until they are out of sight. A squirrel running through heavy cover is impossible to hit with a .22 shot.

Around our house one family of grays has resisted all of my disciplinary efforts by living under a heavily vegetated fence line in a burrow which I have been unable to locate in many years of bemused observation. These guys seem to have learned that it’s o.k. to run across the utility cable from the tall cedar hedge to the edge of the stone house roof to get to a maple which leads to the walnut tree, but any further incursions onto the roof will result in death.

Yes, they learn rules. During a long renovation on our stone house we lived twenty miles away in town. The grays learned that as long as my truck sat outside the house, they had to stay out of sight. My mother lived on the site in another wing of the same house. She used to joke that as soon as my truck cleared the end of the driveway, the squirrels would be all over the lawn.

The most vulnerable time for squirrels is in late winter and early spring when they spend a considerable part of their days browsing elm buds. Once the leaves come out there are lots of bird’s nests to raid for eggs and chicks, but we don’t really know what they’re up to because they are hidden in the dense foliage until the young ones come out to explore their new worlds. Five or six adolescent grays in a game of tag through a row of maple trees is quite a show.

But of course the question is, “What should you feed a squirrel?” Any bird feeder owner can answer that: sunflower seeds. If you want willing subjects for animal intelligence experiments, try keeping the grays out of your feeder. You won’t succeed, but you’ll discover that the squirrels seem to enjoy a good battle of wits.

https://rodcroskery.wordpress.com/2008/09/11/sarah-the-squirrel/

In Eastern Ontario turkey vultures arrived in 1969. We didn’t know what these strange birds were. Thinking it was a goose, my room-mate from Toronto shot one. That was my one up-close encounter with this spectacularly ugly bird. Its beak was strange. I could see through it: a big hole for nostrils with what must have been scenting equipment lying below the holes. But the consistency of the beak was even stranger. It reminded me a great deal of my thumb nail, flexible and not very thick.

A Canada Goose would be a more formidable predator than this critter.

While commuting to Smiths Falls for my first teaching job I began to pay attention to these ungainly birds after I noticed how a pair had figured out Hwy. 15 traffic.  A tasty bit of carrion lay on the pavement near the centre line on an open section of road.  These two evidently had decided that it wasn’t worth the effort to fly away from their feast every time a car came by.  They simply stepped across the centre line to the other lane and waited for me to pass.  That was pretty smart.

Turkey vultures always loved the buildings on the farm, especially the tall Victorian house jutting up from the side of the hill.  I gradually realized that the expert sail planers were using the air currents for altitude.  A couple of loops around the roof of the brick house on a hot day and the bird would be off on his afternoon glide.  The lazy birds love to glide, and put considerable intelligence into perfecting their craft.

Many years later I was forced to abandon the barn on the property when the foundation collapsed but the timbers still held the thing in place a few feet downhill from its original position. It was too dangerous to enter. Expecting a quiet abode due to the diminished activity, a pair of ravens spent the late winter building a nest somewhere on the second floor, but then they abandoned it because I persisted in mowing the lawn around the barn. A family of vultures sat on the peak of the smooth metal roof of the barn and pondered these developments. Eventually they decided that my wife and I were harmless, though they made themselves scarce if strangers came around.

So for the last three years we’ve gotten to know a group of five turkey vultures. It’s clear their evolutionary advantage is their brain power. They recognize human faces. They observe. One of the summers I conducted trench warfare with the local raccoon population over a stand of sweet corn in my garden. After I had live-trapped and euthanized sixteen raccoons and had harvested a mere three dozen ears of corn, I gave up. By that time the vultures had learned that if I started my UTV and drove it down the hill to the garden, game was afoot. They’d be circling my carcass-dumping ground in a distant field by the time I got there.

Waking up in the morning is a chore for turkey vultures. The sun gradually thaws them out and they extend their wings a little bit and they seem to freeze there. Then the wings go out a little further to let the dew dry off. Much later, someone will try a tentative flap or two. Eventually one will catch a breeze and lift off the peak of the barn.

Then one morning I watched a sleepy vulture put a foot wrong and begin to slide down the long, smooth slope of the roof. He didn’t panic and flap, just controlled his slide, gained speed, and gently lifted off in a glide. From then on more and more of them tried this approach at the first hint of a breeze in the morning. They seemed to get a big kick out of their playground slide.

This year it was clear that someone was nesting in the barn, rather than merely using it as a roost. That fact slipped my mind when I needed a trailer wheel from the abandoned barn, so I wiggled through a collapsing door, hopped four feet across a chasm onto the rickety second floor, and with some trepidation located the trailer wheel. I heard a scuffle behind me and turned around to see a large turkey vulture frantically trying to fly straight up and over a beam 14′ in the air, and then make her way across two other similar beams and down through the open door to the other bay of the barn.

Turkey vultures don’t look all that big when they’re 200′ in the air. Inside an empty hay mow, trying to escape, the same bird is huge.

After the insult to his mate, the largest of the birds circled me steadily whenever I was outside the house. Then I guess he forgave me.

A couple of months later the barn fell down. It was far from sudden. At first it sounded like a heavily-loaded farm wagon being towed down the paved hill road, over bumps, but with no wheels. This went on for about fifteen minutes, amid a great cloud of dust. It had been very dry. The lime mortar in one section of the wall must have failed and the wall fell apart.

The vultures were quite perturbed about this noisy re-location of their home, but they continued to perch on the collapsed roof for several days, then one by one they went away. Except for one. She maintained a vigil over her lost nest for two weeks to the day. Others came back to visit her, but I don’t think she left to feed or drink, though I wasn’t watching all of the time. And then she was gone.

I should mention in conclusion that I detest pigeons because of their filthy habits.  Our turkey vultures were very tidy birds:  there were no streaks on the steel of the barn roof, even after years of summer roosting.  As neighbours they were polite and clean.  While up close they were far from beautiful, when aloft they moved with grace and elegance.

Not bad neighbours at all.

UPDATE, 8 April, 2017

Three of them were awkwardly perched in a dying maple to confront me as I drove the Ranger out of the woodlot.  “Where is our barn?”  In their demeanour and attire they looked like a trio of pencil-necked old guys at a funeral.  I explained as well as I could that the barn was still there, just lower and spread around in unsightly piles.

They eventually soared off to a dead raccoon one field away.  Then today I came out of my shop and the three were trying out the roof of the brick house as a new residence.  Enough was enough!  I shouted at them and they flew away, rather apologetically, I thought.

Maybe they’ve been reading my blog.  Good fences and all that, guys!

Skunks

February 19, 2016

This morning a Quora contributor asked “Is a skunk good for anything?”  I felt compelled to respond:

A healthy skunk is a fine garden companion in that it has a great appetite for grubs, insects, small rodents, and little desire to destroy vegetables.

Skunks have beautiful pelts. In the 1930’s “Alaskan Sable” was one of the most fashionable coats. Truth in manufacturing legislation put an end to that fad: nobody wanted to be known to wear a “skunk” coat.

At the height of the depression my grandfather dug out a skunk den and harvested the hides to buy warm winter clothes for his family. In Canada agricultural products were almost worthless during the dirty 1930’s, but fur prices remained high.

Skunks have many PR problems, though. Most notably, most tend to spray when rattled by dogs, loud noises, passing tractors, or inquisitive seniors peeking into their dens. During a local infestation of Japanese beetles many home owners discovered their lawns methodically torn up by these nocturnal foragers.

Rabies is the scourge which wipes out skunk populations as the virus is an aerosol, spreading by air to the eye membranes of all members of a hibernating colony, be they bats, racoons, or skunks.

Skunks have even less road sense than raccoons, so on moist summer nights when the frogs are migrating, passing cars take a fearsome toll.

Some years ago we had a large skunk on the property. He lived in a pile of rails along a fence row, peaceably interacted with the wolves and raccoons, and somehow avoided encounters with our dog. Trouble was I needed to mow around the little trees planted in the field next to his rail pile, and he was a little incontinent when a tractor went by. Just a little. So every three weeks the poor skunk would have a fume-filled morning.

Then one day a bus load of tree huggers dismounted in our yard for a tour of the woodlot. After several hours confined to the coach, they had scattered like cats when released. I used a bullhorn to round them up, instructing them to proceed west until they smelled the skunk, then to turn south and follow the path to the woodlot. One elderly but very alert gentleman in dress shirt, shorts and bare feet made a beeline for the pile of cedar rails and peered in, looking for its occupant. This was too much for the poor skunk. Fragrant, but unchastened, the gentleman rejoined the group.

That summer during a pitched battle with local raccoons over several rows of sweet corn in the garden, I captured the skunk a couple of times in live traps. Most of the time a tarp over the metal frame would keep him calm enough that I could release him, but for some reason one day I delayed the release and felt compelled to give him a drink of water against the sunny day. This didn’t go so well and we both stumbled back to our respective dens in embarrassment. After that he avoided the garden.

One spring years ago we needed a supply teacher for a week at our school and my colleague Elizabeth Docker had a sister visiting who was willing to help out.  Margaret had just completed her  PHD in biology at the University of Guelph.

At the time I was writing a young-adult science fiction novel, and when I discovered our new English teacher specialized in fish, our talk drifted to the semester Margaret and her classmates made salmon fry grow very large by manually destroying the gene in the egg which limits growth.

They used the tiniest pipette they could find, heated it in a bunsen burner until it melted, then twisted it apart until a tiny shard of glass protruded.  With an electron microscope they could carve away at fertilized salmon eggs with this improvised tool and actually damage individual genes.  Apparently the growth-regulating gene is easy to find and shut off.

The salmon fry which hatched grew really big, about 30 times the regular size.

In further research I read a newspaper account of a similar study in New Zealand which ended, not when the test specimens hit 750 kg and took on a scary green hue and huge lumps on their skulls, but when the scientists doing the work realized the things were fertile.

Current news stories have a Canadian aquaculture company raising Chinook salmon with an eel chromosome in fresh-water tanks inland in Panama, but also another company raising double-sized Atlantic salmon in saltwater pens in Nova Scotia.

My friend Dr. Martin Mallet is a geneticist and president of the New Brunswick Shellfish Grower’s Association, so I emailed him an open-ended question on the topic.

So, Dr. Mallet, what do you think?

Martin:  My understanding is that these new GMO salmon are to be sterile females only (though I suppose there must be fertile broodstock somewhere).  

Regardless, my biggest beef with this is not so much with the technology itself as with the production and economic system it embodies. I do not want to see the mistakes of intensive agriculture repeated at sea.

Here’s a similar example: 

Total North American cattle inventory in 2014 was about 100 million head. Peak Buffalo population in North America before we exterminated them? about 100 million. 

So instead of responsibly managing a wild resource, we’ve come up with our own pathetic approximation, a heavily subsidized, unsustainable and polluting one at that. 

How is this different from your oyster operation?  Is it not a feedlot as well?

Martin:  Hardly. We don’t feed the oysters anything once they’re out to sea, so we’re not relying on non-renewable resources for our production, with the exception of gas for the boats and plastic for the grow-out bags and buoys. I’ve not done the formal calculations but I estimate that those costs are largely offset by the carbon oysters capture in their shells. Oyster abundance is historically low, so we’re contributing to restoring some of the lost ecosystem function by adding to the oyster biomass in our bay, with many of the same advantages as natural reefs (filtering capacity, habitat for small fish and crustacean etc..). On top of that, cultured oysters spawn and their offspring are able to colonize available habitat so are much more likely to contribute to wild stocks rather than harm them.

I would argue that the gap between farmed and wild is much much smaller in shellfish culture than in almost any other food production system. If I believed I was doing harm, I wouldn’t be doing it.

Of course, that doesn’t guarantee I’m not doing harm.

My other learned friend Roslyn Dakin, an evolutionary biologist, is completing post-doctorate research on hummingbird flight at the University of British Columbia.

Dr.  Dakin, what’s the view on genetically modified salmon from the west coast?

I like what Martin has to say. I don’t think there’s anything inherently or necessarily bad about genetically modified fish. Same goes with genetically modified plant crops. I’m all for both, if they would solve problems that result from having to fuel so many humans. The classic example is artificial selection – every domesticated animal and plant is the result of genetic modification by many generations of breeders. The question is, do we have the right incentives and regulations to avoid harm by a GM fish industry?

It’s also interesting that just the idea of genetically modified whatever can be so horrifying. The “ick” factor increases the closer you get to us on the evolutionary tree. It’s not hard to sell a GM tomato. But will people buy GM chicken, or GM pork? Also interesting that people in the UK are particularly against genetic modification. Why?

But how about the view in your lab?

The one thing I know is a little bit of the work on wild salmon here showing that their temperature tolerance is remarkably well adapted to the exact natal stream to which they return in the Fraser.
The downside of this is that as the river warms the populations lower in the system will probably be wiped out.  No kidding.

I wonder if the eel-gene allows B.C. salmon to tolerate warmer water?

UPDATE:  9 December, 2015

Dear Rod,

It’s good to hear from you, and I have to say that I’m very surprised that you remembered our discussions after all these years.  I read your blog on GM salmon and, although some of the details are inaccurate (e.g., there is no way that one can manually destroy select genes of interest in salmon eggs while leaving others intact), I’m impressed that you remember the conversations.  I don’t even want to try to figure out how long ago that was!

I hope you’re enjoying retirement.

Best regards, 

Margaret

Margaret F. Docker, Associate Professor

Department of Biological Sciences

University of Manitoba

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Oops!  I guess it’s as my friend Robert Ewart says: my memory is rather flexible on the details when a story is at stake.  Now Rob will  undoubtedly chime up with a correction of this quotation from the dimmest echoes  of last Sunday’s dinner.