Researcher urges support for added shotgun week for deer
On May 23, the Massachusetts Division of Fish and Wildlife Board will hold a public meeting on Martha's Vineyard to hear comments on their proposal to add a second week to the existing single week of shotgun season for deer. The proposal is designed to start reducing the deer herd so that future generations of Islanders may be less burdened by deer tick-transmitted infections, in addition to ensuring a healthy deer herd. Those who know Lyme disease to be a public health problem should attend and voice their support for this proposal.
The current epidemic of Lyme disease, babesiosis, and human granulocytic ehrlichiosis is due to three factors: changes in the landscape promoting mice, ticks and deer; an ever-increasing deer herd; and increased use of the land for recreation or housing. Of these, only the deer factor is capable of being manipulated at an Island-wide level. It is an established scientific fact that deer density is associated with that of deer ticks; each female deer tick, if successfully fed on deer, will lay 2,000 eggs. Each deer may feed as many as 300 female ticks each week for the fall and winter months. Larvae that hatch from these eggs feed on mice, shrews, squirrels, and certain birds and pick up from them the pathogens that cause the three diseases. The fed larvae turn into the nymphs, which are the stage of the tick responsible for infecting people. The number of female ticks potentially feeding on deer explains why each acre of typical Vineyard land will produce 2,000 nymphal deer ticks each year, an estimate I have made from 10 years of research trapping mice and ticks at Felix Neck and Menemsha Hills. Indeed, my research continues with the objective of understanding why we are not up to our neck in ticks, given such numbers.
Reducing the deer herd to fewer than 10 per square mile has successfully reduced deer tick density by an order of magnitude in each of the four sites across New England where it has been tried. (Each of these research efforts are documented in peer-reviewed scientific publications.) MassWildlife has estimated that there are 30-50 deer per square mile on the Vineyard. In order to halve the deer density in 10 years, at least 100 more deer must be harvested each and every year (the current harvest is roughly 500 deer). This gradual measure to reduce deer ticks must be therefore be viewed as a long-term objective that seeks to make things better for our children's children.
Although eradication of deer by sharp shooting would be a faster way of achieving control, this method would be extremely expensive, perhaps costing $5-10 million dollars, and would cause tremendous controversy. Using hunters to achieve the same goal over a more prolonged time means that it is done for free, and in fact, hunters greatly contribute to the Island economy. Other methods have been proposed as an alternative to deer reduction, such as the four-poster or deer contraception, but they have not yet been proven to work or be free of undesirable effects on the environment over the long term; in any case, both methods would work more efficiently if deer numbers were first reduced. Furthermore, these are expensive methods that need to be done forever, begging the question as to who would pay in times when money for essential public health programs such as AIDS education or smoking cessation is difficult to find.
Vegetation management by burning or mowing would powerfully complement deer reduction, but is unlikely to be possible over large areas of the island. Education and public awareness are important tools for reducing the risk of infection, and public forums such as the excellent one sponsored recently by the M.V. Hospital are critical for any strategy to improve health on the Island. Neither, however, would substitute for reducing the source of the ticks.
Much thought has gone into the decision to add another week of shotgun season. A second week will compensate for losses of hunting time due to bad weather, guaranteeing the opportunity for hunters to remove the required 600 or more deer each year. Creative options for increasing the harvest were considered, but rejected due to the recent experience on Nantucket, where an innovative and successful February hunt was rescinded due to pressure from activists who were inconvenienced by hunting during a time of year when none was expected.
More time for hunting is not the final word, however, to reducing deer density and eventually that of Lyme disease prevalence. Landowners who prohibit hunting access do themselves and the community a great disservice because deer can be smart and hide on their land during hunting season. More ticks would be expected on such properties and deer that survive in the no-hunting refuges will emerge and go back to other areas that may have had their deer numbers reduced. Citizens who would like to do something about the prevalence of Lyme disease on the Island should work towards getting more land open for hunting. Finally, because responsible hunters only take as many deer as they can use, the community must make prior arrangements to use as much venison as possible, for example by expanding existing food banking programs for the under-served. Creating a demand for venison will help hunters take more animals.
The time to act is now. We cannot wait for the perfect humane solution to the Lyme disease problem. Money is not going to fall from the trees to fund alternatives to deer reduction, particularly ones that are currently unproven. Deer reduction has been conclusively demonstrated to reduce the number of deer ticks. The proposed additional week of shotgun season will help achieve this goal.
Sam R. Telford 3rd is associate professor of infectious diseases at the Cummings School of Veterinary Medicine of Tufts University and a member of the Martha's Vineyard Tick Task Force.