Efforts to reduce the deer herd on Martha’s Vineyard and an apparent spread of lone star ticks topped a presentation this week by tick expert Richard Johnson.
About 30 people attended the presentation Monday at the Agricultural Hall in West Tisbury. Mr. Johnson outlined his work leading the Island’s tick-borne illness reduction initiative, including efforts to target white-tailed deer, which provide food and habitat for ticks at key stages in their life cycle.
“I’m like a preacher on this,” Mr. Johnson said in the meeting room, where fall-like weather made its way through the open doors and windows. “Until we reduce the number of deer, I think we are just [using] Band-Aids.”
In response to letters from Island towns last year, the state Division of Fisheries and Wildlife has agreed to discuss an earlier start to archery season, which usually opens on Columbus Day. A public hearing on the Island has not yet been scheduled.
Mr. Johnson is also working with private landowners to open new areas to hunting. He noted one estimate that reducing the herd from about 40 to 12 deer per square mile could break the Lyme disease transmission cycle, although similar efforts in the region have had mixed results.
Island hunters check in about 625 deer per season, said Mr. Johnson, who speculated that increasing that number to 750 could reduce the deer population over time, although more study is needed to understand the population.
At the talk on Monday, Island Grown Initiative executive director Rebecca Haag announced that her organization has agreed to provide an on-Island facility for processing the deer meat, potentially clearing a major hurdle in the hunting efforts.
“We are a natural program to work with the hunters,” she said, noting that Island Grown already distributes food to many groups across the Island. She called for volunteers to help distribute the processed meat when the time comes.
Discussion focused mostly on deer hunting, with some people pressing for a more aggressive approach in light of the spread of lone star ticks in recent years.
“It’s not a sport,” Peter Harris said of the hunting efforts, favoring a more concerted push to reduce the number of deer. “I think it would be great if we found a good use of the venison, but the real goal of this is reduction in these tick-borne diseases.”
Guy Tufo asked about hiring sharpshooters, and worried that the risk of tick-borne illness could drive away summer residents. But those involved in the Island tick program favored a more measured approach, at least partly in light of the political consequences of moving to fast.
“It’s a big jump to go from nothing to sharpshooters,” said Edgartown health agent Matt Poole, who has helped guide the tick program since 2011. He added that not having a way to deal with the additional carcasses would create “a political disaster.”
Mr. Johnson agreed, arguing that Island hunters themselves should be the first line of defense, and he noted that funding has been limited. As a plan B, he said, the Island may want to consider more drastic approaches, such as baiting the deer and hunting at night. And he welcomed others to take up their own causes. But for now, he said the current efforts were a big step forward.
“For the first time, we are saying we are going to reduce the deer herd,” he said.
The Island tick program began six years ago with a major grant awarded through the Martha’s Vineyard Hospital, but that money ran out last year. As of Monday, Mr. Johnson had raised about $10,000 toward a $34,300 goal for next year, with pledges covering about half the remaining amount. A grant from the Martha’s Vineyard Vision Fellowship has also supported his research and outreach efforts.
The budget for next year would include the hiring of three interns to expand a yard survey program that Mr. Johnson has been offering to Island residents, along with subsidies for the processing and distribution of venison to those in need.
“Next year we will have more people and we are going to do a heck of a lot more surveys,” Mr. Johnson said of the yard program, which helps people evaluate their property and take preventive measures, including the removal of dead vegetation and the spraying of permethrin or other insecticides.
The surveys have also helped document the presence of lone star ticks, formerly a southern species that has spread across the country, including as far north as Maine. A new map shows the distribution of lone star ticks on the Island, although Mr. Johnson said that may be the tip of the iceberg.
“I’m convinced that next time you see this map, there will be a heck of a lot more dots in Aquinnah and Chilmark,” he said. He added that lone star ticks have been spotted in Katama and on Lambert’s Cove Road, and while he hasn’t done much work in the Island’s interior, he expected to find lone star ticks in Oak Bluffs, which has the same type of pitch-pine habitat where he has often found the ticks.
“We don’t know what to do about these darn things, and its seems like we’re poised to have a big spread of them across the Island,” he said.
At the same time, he said, lone star ticks may be responsible for an apparent increase in tick-borne illness on the Island. A small percentage carry ehrlichiosis, tularemia or southern tick-associated rash illness (STARI). Lone star ticks may also trigger a potentially life-threatening allergic reaction to red meat, but those cases are rare.
Mr. Johnson said an apparent abundance of rocky mountain spotted fever on the Island may in fact indicate a less serious version of the disease that is transmitted by lone star ticks, but he has yet to confirm the link.
One goal for the tick program is to determine the species’ feeding habits, which could inform management strategies in the future. Mr. Johnson said he hoped to collect a large number of ticks and send them away for DNA testing. “If they are feeding on raccoons and skunks, we’ve got an issue,” he said, noting the abundance of those and other introduced species on the Island.
Some have suggested using guinea hens or turkeys as a form of biological control, since they feed on ticks, but Mr. Johnson said he hasn’t found evidence of that strategy being used for lone star ticks anywhere else. He added that in many places, lone star ticks are known as turkey ticks, and he worried that turkeys may also be part of the problem.
It’s likely that at least some of the ticks are arriving on seagulls and shorebirds, which would correlate to the apparent hot spots on either end of the Island.
As for the deer, the absence of coyotes and other predators has allowed the herd to expand. And the absence of predators such as red foxes has likely benefitted the population of white-footed mice, which serves as the primary reservoir for Lyme disease. Lone star ticks do not carry Lyme disease and tend not to feed on mice.
Mr. Johnson joined Ms. Haag in calling for volunteers to help spread the word about tick-borne diseases in general, including through similar talks around the Island.
“There is a lot of work to be done,” he said.
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