From dusk to dawn, drones were flown daily this winter from more than 100 spots across the Island to collect and mark the heat signatures of deer, in what is regarded as the most extensive survey of the herd ever done.
Now the results are in. The nonprofit Tick Free Martha’s Vineyard (Tick Free MV), which commissioned the study, publicly released the report yesterday that confirmed that the density of deer on the Island is approximately 53 per square mile, and that in certain hot spots, such as Chilmark and Aquinnah, there are two to three times higher densities of deer. The goal of the survey was to obtain accurate data on the deer herd, the primary host for ticks, in order to help health officials and wildlife managers control the herd and thereby reduce tick-borne conditions.
The survey of the deer population was carried out from preapproved spots by independent conservation nonprofit White Buffalo from mid-February to mid-March. The Connecticut-based contractor counted a total of almost 5,000 deer on the Island as of mid-March.
To be precise, pilots counted exactly 4,681 deer over 87.7 square miles, which means a count-based density of 53 deer per square mile on the Island. The state’s target is 12 to 18 deer per square mile, which is the case in most of Central and Western Massachusetts, in order to reduce property damage and maintain public safety, forest health, and public health.
And while 53 deer sounds slightly better than the more than 55 deer per square mile (and 100 deer per square mile in areas closed to hunting) estimated by the Division of Fisheries and Wildlife (MassWildlife), the results from this survey are much more nuanced, and several hot spots on the Island yielded much higher densities.
The highest density was reported in Aquinnah. A total of 533 deer were counted within 5.3 square miles, which is 101 deer per square mile. Next was Chilmark at 85 deer per square mile; 1,520 deer were counted in 17.8 square miles. The lowest density was recorded in Oak Bluffs at 19 deer per square mile. (See table for the rest of the towns.)
The survey was conducted at the lowest herd count of the year — both after 934 deer were harvested this fall and winter and before the birth of fawns in May and June. Jason Boulanger, head of research for White Buffalo, previously told The Times that the reason drone surveys are normally done in the winter for East Coast states is because there’s a higher contrast for the thermal cameras when the ground temperature is cold. The report submitted by Boulanger said that the count “likely represents a minimum number of deer present at the time of the survey.” In a statement about the survey, Virginia Barbatti, executive director for Tick Free MV, concurred.
The three rotor-type drones used by White Buffalo allowed the surveyors to hover, inspect specific areas, and operate at various heights. The report said that the “integrated laser range finder” could measure object coordinates up to 1,200 meters away. White Buffalo preprogrammed a transect, a straight line or path used in a study, of each property, and flew in evenly spaced and parallel flight lines that started in Aquinnah and moved east. The drones flew at an altitude of 250 feet and at a speed of 15 miles per hour. Once a deer was spotted, the drones were switched from the automated transects to manual flight, and the pilots recorded each individual deer. “The pilots could pause, hover, circle specific areas, zoom in, and adjust angles as needed to account for heat signatures that could be obscured by vegetation or structures,” the report stated.
Most of the Island was surveyed between Feb. 17 and March 9, and then after some weather disturbance, Chappaquiddick Island was surveyed from March 18 to 19.
Boulanger recommended in his report that the Island continue to do annual surveys to establish an index of deer abundance over the years. He said that this could detect shifts in deer density and ecological impacts, and allows managers to adjust harvest quotas and make informed decisions.
Tick Free MV, created at the end of last year, is the backbone of an Island-wide tick strategy to reduce the number of tick-borne disease and allergies on Martha’s Vineyard. This was just one step, though the group also recently supported bills filed by Gov. Maura Healey to expand hunting access, and advocated for the state to track alpha-gal syndrome, which was recently made a “reportable condition” within the state Department of Public Health.
“This is a multiyear undertaking that will require multiple interventions to dramatically reduce the overabundance of ticks in the environment,” Barbatti said in a statement for the report. “With deer being the primary reproductive hosts for ticks, our initial efforts will focus on ways our community can come together to manage the deer herd to a level that improves our public health outcomes as well as maintaining the Island’s ecology and biodiversity. We now have data to share, and look forward to engaging with the community to digest the results and discuss what comes next — together.”