Updated May 6.
A reduction of deer densities on the Island wouldn’t necessarily mean an immediate decrease in the amount of ticks, but any efforts could make other strategies, such as chemical treatments, managing other host populations, and other solutions currently in research much more efficient and effective.
That’s what Martin Feehan, deer and moose biologist for the state Division of Fisheries and Wildlife (MassWildlife), made clear as part of a panel of experts on the Island-wide deer aerial survey. The public panel discussion and Q and A was held last Thursday, organized by the nonprofit Tick Free Martha’s Vineyard, which also commissioned the survey. It included Feehan; Virginia Barbatti, executive director of the nonprofit; Joseph Capece, president of the Martha’s Vineyard Hunt Club; and Patrick Roden-Reynolds, public health biologist and director for the Martha’s Vineyard Tick Program.
How the Island actually reduces the amount of deer, and eventually ticks, remains in the works. And while deer sterilization was brought up, the idea was shot down by experts as not a sound option for a place like the Island.
The event, held at the Agricultural Hall in West Tisbury, was a means to educate the public on the survey conducted by independent conservation nonprofit White Buffalo. The survey cataloged deer counts after drones flew from more than 100 spots from mid-February to mid-March. The results counted 4,681 deer, and estimated the Island’s deer density at approximately 53 per square mile. Some areas in Aquinnah and Chilmark, though, and on Chappaquiddick, are much higher, at more than 100 deer per square mile. This aerial survey, Barbatti said at the event, was the initial step for Tick Free MV to reduce the amount of ticks on the Island.
But Barbatti said that reducing the tick population can’t be discussed before deer on the Island are properly managed, and that even making a plan to do that was a bit premature for the panel last week. “We’re not going to be laying out a strategy for what to do about the deer,” she said. “We’re at an earlier stage than that. We’re sharing the information that we got because we believe that the community deserves to have the best possible information so we can have shared conversations about what to do next.”
Barbatti told The Times, “It is clear that we need to take action. These survey results are a call to action for our community. We want to hear more from residents as we build a plan to address these high deer densities.”
The biological relationship between deer and ticks isn’t direct, though the large mammals do host the small arachnids, and Roden-Reynolds said at the panel that there are a number of factors that influence the prevalence of ticks in a yard and tick-borne diseases in humans. For example, dependent on their life stage, ticks can prefer smaller animals, like mice and shrews, and though born sterile of illness, when they bite an infected host, they can acquire disease that can be later passed on to humans.
But deer are important to the reproductive cycle of ticks, because typically bigger and older ticks prefer bigger hosts. And “when deer densities are high enough, an area reaches a ‘saturation point,’” Feehan said, where enough deer are able to effectively host an unlimited amount of ticks.
Based on the deer survey, Feehan’s data from his own tick surveys across the Island, and disease data from public health officials, there are consistencies and overlap between areas of high deer and high tick densities. There are also places closed to hunters that match up to where there are pockets of high deer and tick densities. A lower density was recorded by the drone survey in spots, like the Manuel F. Correllus State Forest, which has very large, consistent, and continuous tracts of land open to hunters.
The eradication of deer isn’t a silver bullet for the Island’s tick problem. But, Feehan said, even if this isn’t a one-to-one relationship, deer reduction and deer population management can make tick reduction strategies more effective. Still, he added that studies have shown that once deer densities drop below 12 deer per square mile, tick reductions start, and “crash out” when they get below eight deer per square mile.
Hunters are one way to help, and there are plans throughout the state to extend the season and make the sport more accessible. But Capece highlighted that access to land remains a big issue, especially as the Island becomes more developed.
Roden-Reynolds said that “targeted interventions” would make the greatest impact. This is because ticks spend most of their life off the host — in leaf litter or elsewhere in the landscape — and feed only about three times in a life cycle for a week or so.
“We can either disrupt the adult ticks feeding on deer to kind of break that reproductive cycle, or, in a way, reduce the number of hosts that are available for the ticks to find and feed [on],” Roden-Reynolds said. “Because basically, right now, there’s just enough deer out there specifically for reproduction that the ticks have no problem finding a blood meal and producing larvae for the next season.”
This is especially true for lone star ticks, which can cause the red-meat allergy alpha-gal syndrome in humans, and use deer as a key host. Feehan, however, said that they can move through all the stages of their life cycle on one deer, and so they can reproduce on a smaller number of hosts.
“Even if you got rid of almost all of the deer on the Island, you got rid of 95 percent of the deer, there would likely be little to no reduction in terms of lone star ticks, unless there are other strategies, like treatment, included,” he said.
Tick Free M.V. representatives said there’s not a concrete plan yet on either deer management or tick eradication, but they hope to create one alongside public policy and health partners, with input from residents. When asked about deer sterilization, Feehan said that would be an expensive venture, costing at least $1,000 per deer. He added that sterilization hasn’t been done in a place as big as Martha’s Vineyard, and devoid of predators, the deer can just continue to reproduce, so the Island isn’t a realistic place to do that.
“This was an exceptional group of panelists discussing such an important issue,” Barbatti told The Times. “I am grateful that Martin came to share his perspective as the state deer biologist, along with Patrick as the local tick biologist and Joe as a longtime local hunter. This deer survey makes clear that there is major work to be done to address the high deer densities on Martha’s Vineyard. Deer are the primary reproductive hosts of ticks, and we can see from the tick saturation curve that Martin presented that reduced densities will be essential to our efforts to reduce tick abundance.”
A recording of the panel discussion will be available soon, and there will be another presentation on the survey as part of the Martha’s Vineyard Museum’s discussion on ticks on May 21 at 5 pm.
Editor’s note: Updated to include more context and quotes from Virginia Barbatti.
Next door to the Vineyard on Naushon Island we saw arriving coyotes reduce our deer herd 80% in the late 1980s, yet we still have heavy tick densities of all three species that feed on humans and high incidence of all the tick borne diseases and alpha gal. Perhaps the saturation model is a good one as proposed here and we have not gotten low enough deer populations, but we are down to about 10 or 15 deer per square mile, down from about 60 in the early 80s. Our most successful approach to tick borne disease has been self-protection. Over the past ten years we developed a permethrin treated oversock we call Ticktogs that provides a complete barrier over the foot and lower leg, where ticks hop onto a walker. We have made up a batch in Fall River and treat them at Insect Shield in NC so they repel ticks for seventy washings. They have helped us a lot and this year we have made them available outside our community. You can search Ticktogs to find them. Goal: zero tickbites.
In light of the recent drone count indicating a slight decrease in the deer population since the state did their count years ago, what do the tick experts attribute the explosion of tick related hospital visits to?
A reduction from 100 deer per square mile to 8 or fewer per square mile is needed. Your local friendly hunter is not going to achieve even half that goal. It is pretty clear to me that the people on the panel agreed not to take the conversation further and discuss the part involving a mass cull, otherwise known as professionals in helicopters operating 24/7 using night-vision goggles and rifles, not shotguns and black powder firearms like hobby hunters are restricted to.
I have mentioned this in the past, and it probably did not get through since half my comments get censored: we need to make the whole island available to any SWAT or police departments that want to come here, pay off-season hotel rates in Nov through February and have open season on our deer for target practice, day night weekends, whenever. We then need to hire helicopter sharpshooters with sound suppressed rifles in March and April, before the trees fill in with leaves, and have them reduce the population on both public and private land. This could be authorized by declaring a public health emergency, which we are obviously already facing.
The only part to figure out is how to keep track of all the corpses and harvest them for food as well as how to inform people that the hunters are in their area and how to keep the inevitable PETA nut jobs from interrupting the whole process.