Archive

Disease and Parasites

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Spring is in the air. Yesterday was a very nice, late winter’s day (actually, the 1st day of spring), although by evening the wind was howling, the temperature was plummeting and snowflakes were being blown around. But earlier, it had been a nice day.

It’s been a weird winter. For the first time since I’ve lived here – over 35 years – most of the winter saw the snow with a hard crust, the kind you can walk on. In fact, I’ve looked at snow records for this area that go back to 1955 and see no indication of a winter with similar snow conditions.

I don’t know how that’s going to play out for the local wildlife, but I’m inclined to think not too badly. During our daily walks with our dogs, we are regularly seeing snowshoe hares, ruffed grouse and deer. On the other hand, there aren’t near as many hares as there were earlier, a testament I’m sure to the hunting success of the lynx, marten and fox, the tracks of which we regularly encounter, but seldom see.

And while there remains a small herd of about 7 deer on our property, we note they are regularly harassed by wolves. We haven’t seen any wolves of late, but every few days their tracks show us they are still nearby. Neighbors have told us the wolves have killed at least a few deer in the past weeks near them. It’s a concern that in our drives away from town, we see few – very few – deer tracks. No signs of moose at all.

With so little big game, it’s hard to see that wolves didn’t suffer. Wolves can’t thrive on a diet of mice and hares. Research has shown that each wolf needs about one adult deer every 20 days over the course of winter just to survive. But wolves are, if anything, survivalists. I admit I’m amazed there are as many wolves as there are. When the deer population crashed four winters ago, I would have thought the wolf population would have followed suit no more than a year or two later.  Still, it’s only a matter of time.

Despite the recent melting, there’s still a covering of snow on the ground and it’s still dense enough to support one’s weight. Like I said, yesterday was nice; it was sunny for most of the day and the temperature got to about +80 C.  Last night it dipped to -150 C and isn’t supposed to get above the melting point again for another couple of days.  There’s a lot of ice on the local lakes – more than two feet on the lake where Lil and I went fishing yesterday, so ice-free days are still off a bit (yes, we did catch some fish. Tasty speckled trout, as a matter of fact).

On a gloomy note, I received a report last week on the state of chronic wasting disease (CWD) in North America, the prion, brain-wasting disease now found across wide swaths of North America that’s killing off white-tailed deer, mule deer, elk and even moose. CWD continues to spread and once established in an area, seems to be impossible to eliminate. Once an animal is infected, death always follows. Some of the models being used to predict the outcome of this plague suggest that local, perhaps widespread extinctions are possible, if not probable.

What a mess.

Oh well, it’s spring! No time to get depressed. Plenty of time for that later.

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I just returned from Brandon, where the 50th Annual North American Moose Conference and the 8th International Moose Symposium were combined and held. There were people from North America and Eurasia attending the meetings, but I only managed to intermingle for a short while; I was a one day attendant during a set of meetings, field trips and social events that lasted several days. I really enjoyed myself and it seemed to me that was the feeling that captured the general mood.

I heard several talks about moose and listening to those presentations was like music to my ears. I heard that as a species, moose seem to be faring well, although populations in some areas have declined precipitously. I live in one of those areas – northwestern Ontario – I was there to provide an overview of the factors driving moose and white-tailed deer populations in the Kenora District of Ontario.

I don’t think my presentation was quite as lucid as I had hoped and I know I made an error when I couldn’t see the labelling on one of the graphs I had inserted into the power point presentation. Unable to read the labels and the legend, I promptly got the deer and moose stats wrong. Oh well, that will be corrected during the final write-up and anyway,  I think the crowd got the gist of my presentation.

It’s still an emerging consensus, but it appears that in much of eastern North America’s moose range, moose populations are limited by the presence of a parasite called brain worm. In that eastern, wetter, more highly forested biome, the parasite is commonly found in populations of white-tailed deer, where it seems to affect deer minimally, if at all. However, when moose become infected with brain worm, the animal often dies.

In the western, drier and more open ranges of North America, there is little to no incidence of brain worm in deer or moose. The presence of brain worm seems to do a good job of helping to explain how moose populations are compromised by high populations of deer.

It seems that in the east, once deer densities exceed about 4 deer/km2, moose populations decline. When deer densities are low, rates of transmission of the parasite from deer to moose rarely occurs.

There’s a lot more to the stories on moose and deer dynamics, but one of the topics of interest is how moose recover from low densities. In western Manitoba, southern Saskatchewan and south-eastern Alberta – the Canadian prairies – the thinking is that moose populations have been on the rise coincident with a decline in the number of rural farmers and ranchers living on the landscape. There’s evidence that incidence of illegal, unregulated hunting wasn’t necessarily high, as moose populations were long-depressed in the prairies, but it didn’t take a lot of moose hunting to keep populations low. As people abandoned their homesteads, more and more moose managed to find refuge and survive. Today, moose populations in grain and cattle country are robust.

The eastern forest areas where moose have recently declined are the same areas where deer populations simultaneously surged. But recent winter of deep snow and cold have knocked deer populations back; if they stay low or decline further, moose populations may be poised to recover.

A growing concern is that where moose populations are lowest, recovery could be jeopardized by legal, but unregulated hunting (Aboriginals and Metis have the constitutional Right to hunt and fish; the present interpretation is this means the hunting of moose by some can be done at any time of the year and there are no seasons or bag limits on the harvest).

The moose harvest by such individuals may not have to be much to prevent severely depressed moose populations from recovery.

Unregulated hunting is certainly not the only issue regarding moose population (or other game species) recovery dynamics. But to help solve the puzzle as to how to effectively manage moose populations in particular, it’s a factor that needs a lot more attention than society at large has lately been willing to give it.

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We were out checking on our trail cams a few days ago we use to monitor our reintroduced elk herd (one was stolen – an $800 Reconyx; we reported the theft to the police, but it’s ‘not their top priority’). Didn’t see any live elk, moose, bear or wolves (however, quite a few were captured by the cameras) and only a couple of white-tails. I imagine the females of all species are busy with young and trying to be as secretive as possible, while the male deer are dealing with sensitive and fast growing antlers (the bull elk already have some pretty impressive growth!).

Of note, we did see several hen ruffed grouse and all of them had young. Didn’t see too many young poults, though; the ones we did see were smaller than a ping pong ball. But each hen did the ‘I’m hurt! I can’t fly! My wing is broken!’ and tried to lure me away from the young ‘uns. Some tried to scare me off with an ‘attack’, and al were quite vocal; hissing, mewing and doing other calls trying to distract me. I didn’t pester them for too long, just a minute or so while trying to get some photos of the ‘how to act wounded and lure the threat away from the babies’ routine.

One thing; there must have been great synchronicity in the hatch.  Synchronicity in hatching of birds, as well as the birth of ungulates, is thought to be good as it ‘swamps’ predators and helps reduce losses. For example, wolves and bears have an innate ability to know to look for newly born fawns and calves, but there is also an element of learning how and where to look which improves the effectiveness and efficiency of their search. So if the birthing season is prolonged, it gives predators a longer time period to hone their hunting skills to find newborn, good for predators but not so good for the prey. Once the newbies are a few weeks old, though, they have a much greater chance of escaping, as even a little fawn deer or calf knows how to run like the dickens or keep itself behind mom (e.g., a cow moose) as she fends off wolves or bears.

The best way to achieve a synchronized birth is to have a short, intense rut, when most of the females are bred in just a few days. A breeding cycle that drags on for many days, weeks, or even months, can be disastrous. And short, intense ruts are most likely to happen when there is a healthy population of prime, adult males around – they know how to woo the women.

It’s probably not near as complicated in grouse world, but the situation is likely similar. Older, male ruffed grouse might be better suitors than yearling; however, I suspect weather plays a more important role in grouse hatching success and synchronicity in nesting than behaviour. Early May – when the grouse were mating – was warm and dry. Late May and early June, hatching time for grouse, has been wetter and in a relative sense, cooler, which might not be great. Cool and wet weather can play havoc on new-born chicks; they often get pneumonia or other fatal ailments when the weather in inclement. Maybe next time we are out to check on our cameras we’ll see some more grouse families and get an idea on flock size. But at the moment, things are suggesting it could be a good fall for ruffies.

And given the ruffed grouse is one of the best tasting treats in the northern forest, that’s a good thing.

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Today I applied for a spring turkey hunting license in Michigan. Not sure how this will pan out, as there is still much to do before the hunt, if I do get to go.

Let’s look at the list: need to get drawn (apparently, the odds are good); need to renew my passport; need to fill out some forms to transport a firearm into the USA; and, I need to see if there are restrictions this year as to whether I can actually bring a turkey back into Canada from the states. Last year, a few friends hunted in the mid-west, were successful, but were not allowed to cross the border back into Canada with their birds. The problem was an outbreak of avian flu in the states – another wildlife health and disease issue. Anyway, it’s something I need to delve into and find out what the score is. No sense spending all that time and effort to travel and hunt and not be allowed to bring back a tasty bird (if I’m fortunate enough to harvest one!). On the other hand, I’ll have a chance to meet up with some old friends I haven’t seen in a while.

If I can’t harvest a bird that I can bring home from Michigan, I can still hunt in Ontario. Maybe I can do both, as the area I’m looking at going in Michigan isn’t far from Sault Ste. Marie, where there’s a healthy wild turkey population to the east, and a hunt on nearby St. Joseph’s Island. I’ll have to see how events unfold . . .

I really enjoy turkey hunting, but I find it somewhat distressing that a disease issue is once again a factor as to whether I can harvest, transport and consume my (potential) catch.

On my last post, I discussed chronic wasting disease and the fact there was a little bit of good news on that front. Not much, but a little. Despite the bad news about avian flu, most of the wild turkey story is good news. Growing up, there were no turkeys in Ontario; they were extirpated in the 1800’s. Today, turkey numbers in the province (progeny of wild birds captured from neighboring jurisdictions and then live released) are closing in on a 100,000.

There could be more. In northwestern Ontario, I think wild turkeys would do well in the agricultural areas around Fort Frances and Rainy River. After all, there are wild turkeys in parts of adjacent Manitoba, where the weather is similar, if not a bit more harsh. The problem is the government in Ontario, or at least some individuals, believe that because northwestern Ontario is outside the known, historical range of turkey, wild turkeys don’t belong. It’s a consideration which can make sense (one doesn’t want introductions of wildlife made willy nilly), but it’s not as if wild turkeys are exotic to North America.

What seems to have gotten the short shrift in this line of thinking is the fact that the agricultural lands of northwestern Ontario today bear little resemblance to what the landscape – and its associated faunal assemblage – looked like prior to European colonization. And outside of some sort of apocalyptic, catastrophic event(s), there’s no going back to the way it was. That’s nothing but a pipe dream, adhered to only by a small and radical fringe of extreme environmentalists.

However, it is what it is and with no close by Ontario turkeys, turkey hunting for me, at least for the foreseeable future, means going on a considerable hike.

All in all, it’s not necessarily a bad thing. It just could be better.

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About a month ago a good friend from Alberta forwarded me an article he found written by Angus M. Thuermer Jr., reporting on a a study on Chronic Wasting Disease (CWD) in Wyoming. CWD is an infectious disease known to occur in white-tailed deer, mule deer, moose and elk. It’s part of a family of diseases known as Transmissible Spongiform Encephalopathies (TSEs) where the infectious agent is thought to be a malformed protein known as a prion. Prions are not a bacteria nor are they a virus; they are a very strange and poorly understood entity. There is a human form of TSE called Creutzfeldt-Jakob Disease (CJD). To date, no humans are known to have contracted CJD from a CWD infected animal, although there is a variant CJD people have got from eating cattle infected with Bovine Spongiform Encephalopathy (BSE), another TSE. CWD is thought to have originated from Scrapie, the TSE sheep can be infected with.

CWD is a large and growing concern in North America because it’s a relatively new disease (the first known occurrence was documented in the latter part of the last century), it’s spreading and it’s wreaking havoc to deer herds in some areas. There’s no known cure for the dsease and once an animal contracts it the end result is always death. It’s spread into the area of Alberta where I hunt so it’s a particular concern for me and my hunting partners.

Thuermer Jr.’s article said that a study by a University of Wyoming doctoral student Melia DeVivo led her to believe the mule deer herd she was studying could potentially become extinct because of CWD in 41 years. The herd numbered some 14,000 in the early 2000s but had dwindled to half that in about a decade.

There was a lot of information in the article, but a couple of factoids were most interesting. One was that researchers found that deer with different genes react differently to CWD exposure; a key gene found with three combinations of alleles can make a deer up to 30 times more likely to be CWD-positive, depending on which genotype the deer is. That’s good news, because it suggests that over time, it’s possible if not probable that deer herds will become dominated by CWD resistant strains of deer (however, as the researchers point out, the strains that are resistant seem to be relatively rare, which might mean they might not be ‘good’ for the survival of deer in other ways; e.g., deer with the resistant strain might be bad mothers). Still, I think the news there are CWD resistant deer is very good news indeed.

The other good news is that studies have shown that free-ranging elk don’t seem to get high rates of CWD infection, unlike mule deer – and penned or ranched elk. No one seems to know why that is the case. Plus, in 2002, a penned elk herd of 39, purposely exposed to CWD, had all withered away and died or been put down within 10 years – except for a lone cow nicknamed Lucky. Apparently she’s still alive, doesn’t look sick, doesn’t test positive for CWD and has had a calf. So it looks like elk also have natural, genetic or other resistance to CWD.

Interestingly, the area I hunt in Alberta where CWD is problematic in mule deer, also has free-ranging elk (that’s one of them in the photograph) – that haven’t as yet, at least as far as I know, tested positive for CWD. That would seem to be consistent with what researchers have observed elsewhere.

To date, the results of the studies Theurmer Jr. reported on have not been published in refereed journals. That needs to happen; otherwise, these important findings risk being dismissed as mere speculation or musings.

CWD is a terrible disease likely to get much worse before it gets better. For a long time, all the news about CWD was bad. But now there at least appears to be a glimmer of hope that all will not be lost.

And that’s a good thing.

 

 

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On the way home from a fishing trip the other day (one splake), Lil and I spied a cross fox in a field beside the road. The fox was quite cooperative, and let me stop the truck, get my camera out of the bag and take several shots. It looked like it was intent on a mouse, or more likely, a vole, but no luck (although good luck for the vole). Eventually, the fox wandered off.

A cross fox is simply a colour phase of the red fox. Across the range of the red fox different colour phases are often seen, but in this area, the common and classic bright orange red fox is actually quite rare. Most of the foxes here are crosses. They are called cross foxes because they have a blackish cross on their back, across their shoulders.

We also have a fair number of black foxes around. They aren’t completely black, as they still have the white tip on the tail, and much of the fur is silver-tipped, similar to the black fur on this cross fox.

There were a number of fox farms in this region in the middle of the last century, which I’ve been told accounts for the colour phases that continue to be prominent if not dominant in the local population. Ranch furs were selectively bred to provide colour variety, but there were escapes and I suspect that when the fur farms started to go out of business, many foxes were simply released and their genes continue to persist.

Today, wild fox are trapped across much of their range, but their fur value in this area is rather low (particularly the cross-foxes, as colours are hard to match as they vary quite a bit in the amounts of red and black fur they sport). In addition, fox are much harder to trap then more valuable furs like marten, mink and fisher, are not the easiest animal to skin and often have mange, which further reduces the value of their pelt.

Fox can also be hunted on a small game license, but hunting effort here is minimal.

Fox are great mousers (which includes voles) but will also take grouse and hare and other small birds and animals. They also do a fair amount of scavenging on wolf kill, whom they sometimes follow; at a safe distance, of course.

Bottom line – foxes are common in this area, as they are in most places. Even though, sightings are usually fleeting, and so I’m pleased this one decided to buck the trend and let me capture his image.

 

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Seeing as the wolves were continuing to visit our house almost daily, making it impossible to let the dogs out for even a minute without close supervision, we decided it was time to do something to ease the tension.

It was time to do a wolf hunt.

So we went out on the pond in front of the house and froze some bait into the ice, including a moose foot, a deer hide and some marten carcasses.

The next morning, the moose foot was gone as were several of the marten carcasses. The night had been mild, and the moose foot and a few of the marten didn’t have a chance to freeze solidly into the ice before the wolves scarfed them up. But the deer hide was still there, as were some of the marten.

I decided to keep a close eye out and by late afternoon that same day I had made sure not to venture outside for a couple of hours, had kept the noise level in the house low and hadn’t turned on any lights. Around 4:30 pm, I got up off the couch, and looked out on the pond.

Two wolves, tugging at the deer hide.

It took a couple of minutes to get everything organized and to sneak out on the deck. I took aim at the largest wolf and shot. I could tell I hit it, but didn’t wait around to see if it would fall over. Instead I quickly racked in another round and shot again. With the second shot, the wolf went down instantly, for good. The other one ran off to the right – it was safe, as I had only one wolf tag.

The one I shot was a big male timber wolf, over 7 feet long from the tip of the nose to the tip of the tail, and my brother-in-law, to whom I gave it (he’s a trapper), estimated it to be over 100 pounds. It had a bit of mange under the armpits and some wear between it’s shoulders, but  otherwise the fur was reasonably good. We didn’t see any ticks, or any evidence of injuries. The colour was typical gray.

There were wolf tracks on the pond and in the field in the days that followed, but nothing now for a couple of days. Perhaps the other was trying to figure out what happened to it’s mate, or partner. I’m hoping this event has made it and the other wolves in the neighborhood more wary of our house, as in it’s not a safe place to hang out.

Eight deer did show up the other morning, more than I’d seen all year. I’m sure it was my imagination, but they seemed relaxed and happy.

As I have said before, I  like wolves, but I don’t like it when they start to be too brazen. And I love my dogs. A few people I know have been out walking their dogs and had a wolf attack their pet. Several more simply ‘lost’ their dog during the night. I do not want to have that happen to us.

I will buy another wolf tag for 2016. For the rest of 2015, the wolves are safe – at least from me.