January 03, 2023
By Clint McCoy
A lot of us whitetail hunters already have experience in virology, and it began long before we’d ever heard of COVID-19. In the whitetail woods, our Public Enemy #1 isn’t a true pandemic, in that it doesn’t affect deer everywhere, but it’s endemic through much of the continent’s whitetail population. Yes, it’s the virus we deer hunters most love to hate: the one causing epizootic hemorrhagic disease (EHD).
Those are three little letters no trophy buck or buck hunter wants to tangle with. The disease can take all your hopes and dreams for deer season and destroy them. And it doesn’t matter who you are: meat hunter, youth hunter, weekend warrior or trophy-chasin’ diehard. EHD doesn’t care how you hunt or why you hunt — it can impact us all. If the herd in your area has an outbreak, the virus can decimate the population to a point you’d swear whitetails were going extinct.
In most cases, the conditions leading to an outbreak are simple. Lack of rain and low availability of water sources for whitetails create a late-summer supply-and-demand chain that leads to virus spread. Lack of deer water sources during drought conditions leads to high concentrations of animals around the last available mudholes. As the mud increases, the virus vector midge fly Culicoides uses this gunk as a breeding ground. The numbers of these no-see-ums skyrocket. With continued periods of drought, deer demand for limited water elevates, as does the supply of the bad guys. Deer begin getting bitten at these midge fly hotbeds and pretty soon, an outbreak situation occurs.
The virus has three basic presentations in whitetails. In the peracute form, affected deer spike tremendous fevers and can die of viremic shock within 8-36 hours of exposure. The acute form is characterized by fever, water seeking, swelling of the tongue and face and a slower viremia that can produce mortality in about seven days. Finally, the chronic form can last weeks to months and is characterized by less severe disease, lameness, poor hoof growth, poor antler growth and usually less mortality.
Animals that survive the chronic form of EHD gain immunity and can provide the foundational immunity of the herd for the next several years. Fawns born to does with EHD immunity may gain immunity from their mothers, with doe fawns passing it on themselves as they mature and breed. Fundamentally, this is similar to what medical experts hope to achieve with human society as people survive COVID-19 and develop resistance to it.
When To Respond To An Outbreak
If you live in an area that has EHD, hear me now: I feel your pain. My region of eastern Illinois has been known to get hammered by the virus, and last year was an example of that.
By late August, bucks had started disappearing and trail camera intel had plunged. Water was in short supply. I’d cringe mightily driving about during the preseason, witnessing buzzards circling above farm fields or timbers I knew held mature bucks.
With bow season just days ahead, I worried that some bucks on my radar had perished in an outbreak of EHD. Sure enough, by the end of September, word was getting around: People were finding a few dead bucks here and there, mostly along the Wabash or Embarrass rivers. A neighbor found a tall-tined 10-pointer floating dead in his favorite fishing hole. My brother Eric and I found one on a stand-hanging mission the weekend before our Oct. 1 bow opener.
As the season started, I hoped we’d be in the clear. But it didn’t take long to disprove that.
On Oct. 10, I was on my lunch break when Eric called.
“I can’t take it any more,” he told me. “I’m burning a vacation day to go look for EHD victims.”
I was totally against it and harped at him for pressuring the timber during season.
“You can’t bump him if he’s already dead,” Eric quipped.
Three hours later, a text came through: RIP SURVIVORMAN. Dead in the bottom of a dry creek bed with velvet still on part of his rack was one of our target bucks for the season. We thought he’d been shot in the right shoulder as a 3 1/2-year-old but had survived to tell about it, throwing a cool compensatory drop tine on the left side.
Survivorman had been special to Eric and me, a top hit-lister with a lot of fun history we’d shared. But now, nearly two weeks into our season, an outbreak of EHD was apparent, the evidence was mounting rapidly, and one of our best target bucks was dead. I felt we had to do something — but knowing what to do was hard to figure.
How To Respond To An Outbreak
It seemed reckless and haphazard at times, but my little brother and I started walking hunting locations that housed our best target bucks. Keep in mind, it was the middle of October, so this went against all whitetail teaching. We’re conditioned to never enter the woods until the conditions are just right for a hunt.
But we didn’t just go tromping over hill and dale. We went on fact-finding hikes midday, when animals were bedded. We kept the wind in our faces to both reduce alerting animals and to help us pick up the smell of dead EHD deer.
After awhile we started targeting water sources, where most EHD deaths end, and we did so pragmatically. I even started running into a few suspected buck bedding locations. If I bumped a good buck, fine, but you’re not going to spook a buck that’s already dead of EHD. If he were still alive, maybe we could sneak a stand in there right after he bailed. I started packing a stand and a set of climbing sticks in the truck bed for just these moments as a Plan B of sorts. “Bump and dump” during a viral outbreak? Is this real life?
Eric and I also retrieved several trail camera cards during our intrusions, figuring if we were in the area we should maximize our intelligence return for our efforts. One EHD survey trip yielded a couple SD cards that showed a familiar non-typical buck we called “Son of Sam.” He’d survived the outbreak and had shifted his home range a bit.
Again, at the time our efforts seemed a bit wayward and aimless — but looking back on it, we did a lot of things I’ll certainly repeat when we find ourselves in an EHD season again. Scouting on foot, running cameras, identifying areas of high mortality rates and staying positive will all be on my next EHD response checklist.
By Halloween, Eric and I had a reasonable suspicion or physical proof that EHD had killed off several local deer, including a couple top target bucks. We uncovered farms where dead deer littered the creek beds, sloughs and waterways. On one farm I discovered 13 dead deer and, in another location about a mile away, nine more victims. The dead included young bucks, does, a couple mature bucks and even one fawn with spots fading. It was a complete mess.
Once reliable trail cameras had tanked, in-hunt deer sightings in October were low. I was uneasy at the prospects for my November vacation time.
My first day of vacation found me high atop a section of thick, post-logging hardwood timber. A 6-hour sit in one of my most reliable early rut locations was a total bust, with not a single deer seen. At dark, the place just felt like a morgue. On the way to the truck, I mentally gave up on the spot and chalked it up to a loss to EHD.
Out of desperation, I drove straight to an adjacent farm and in the dark pulled every camera I had on the place. A stroke of luck found Sam had migrated even farther, and he’d been all over that farm the previous three days. We’d known him as a fighter and a roamer, and with other farms cold from the outbreak, I threw caution to the wind. I moved from checking SD cards to hanging a set and placing a decoy out near an edge of standing corn. I’d just been there pulling cameras, so it was an easy choice to make a move under the cover of darkness.
At dawn the next morning, Son of Sam read the cobbled-together, rewritten season script. I arrowed him as he was focused on the fake.
The rest of our ’19 season went well, but we really had to scratch and claw to have good hunts and see mature bucks. Once the season ended, the outbreak was still on my mind as several of our usual suspects had vanished. So in lieu of waiting until March to get serious about scouting and shed hunting, I started at season’s end. I began combing my hunting spots for evidence of EHD severity.
Some farms were ghost towns, with several deer found dead. But by summer velvet scouting time in ’20, I felt I had a good handle on which areas that might still be profitable and those that needed more time to recover. As a family, we’ll likely shoot very sparingly this season. There’s a good chance we’ll eat some of our buck tags and even abandon certain spots altogether.
I’ve seen two seasons in which EHD really thumped our local herd: ’12 and then again in ’19. In the former season, I did nothing in response to the outbreak unfolding before me. I hunted familiar spots and “old faithful” stands, but with unusually poor results. The following year was nearly as bad. But I learned from all that. By putting in work and troubleshooting the outbreak in real time, last season was salvaged with my best archery buck.
Unknown, at this writing, is whether or not any part of the whitetail’s range will have a major EHD outbreak in ’20. But if late summer brings drought, muddy waterhole edges and midge flies to your area and you see buzzards start circling, throw caution to the wind. Recognize the potential for EHD, respond accordingly, and stay in the hunt. And once the season starts, avoid areas that just feel dead. Try to identify if your target buck survived the EHD surge, and investigate his current whereabouts.
Will you find a cure for the virus? Probably not. But you might just save your deer season and still end up punching a tag on a trophy buck.