Deer Study: Fewer Than Expected

‘Is the survey faulty?’ the supervisor asks
Durell Godfrey

    The value of an aerial deer-population survey conducted in East Hampton Town in March, which counted 877 animals in its flyover of the town using infrared cameras, was debated at a meeting of the East Hampton Town Board on June 18. Based on the survey methodology, it is not expected that all of the town’s deer were counted and some town officials assume that the deer counted are only a fraction of those that actually live here, the 877 number being far fewer than the 3,293 estimated in a 2006 count. (That number resulted from a “roadside distance sampling” in which only some deer were actually counted. The total was extrapolated from the count.)

    “I have no idea what the value of this survey is. Is the survey faulty?” asked Supervisor Bill Wilkinson. “I assume that we didn’t get what we asked for.”

    “Should we pay the $13,000?” he asked. “What’s the current population?”

    “They ‘surveyed’ 877 deer,” Marguerite Wolffsohn, the town planning director, told him. “That doesn’t mean there are 877 deer in the town . . . The [state Department of Environmental Conservation] is extremely confident that we have too many deer.”

    The recent survey recorded deer concentrated mostly in populated areas, and not in open, preserved spaces.

    “Obviously it did not meet our expectations,” said Councilman Dominick Stanzione. “We expected that it would count thousands of deer and help us set a baseline metric so that we could define the success” of a deer-management program that could include culling.

    Repeatedly interrupting Ms. Wolffsohn, Councilwoman Theresa Quigley appeared incensed with the assumption that the aerial survey did not count all of East Hampton’s deer.

    “I don’t understand,” she said. “We hired these people, we paid them $13,000. . . . But because we don’t like what they say, they’re obviously flawed?”

    “Did anyone in the town reach out to the company and say, wow, do you think there was a problem?” Ms. Quigley asked. “I did,” Ms. Wolffsohn said. “What did they say?” asked the councilwoman. “No,” Ms. Wolffsohn replied.

    The company hired is reputable and widely used in the field, including by New York State, Ms. Wolffsohn said, but several conditions could affect the ability to capture all the deer out there on tape, such as their proximity to houses or evergreen trees, which can block the view even in winter.

    Based on mapping the results of the aerial survey, there are 6.9 to 23.1 deer per square mile in the town. A Cornell wildlife expert later contacted by Ms. Wolffsohn estimated, based on other existing information, that East Hampton might actually have 100 deer per square mile.

    But, Ms. Quigley said, given that the deer that were seen were mainly in populated areas and not on preserved land, maybe the number is correct and people are just seeing deer more often. “It’s absolutely wrong to assume that we know the answer and that we are going to manipulate the data to show that. I agree I think the numbers are peculiar. But I don’t know that they’re wrong.”

    The D.E.C., Ms. Wolffsohn said, does not attempt to pinpoint actual deer population numbers but uses information such as the annual hunting “take” in a particular area as an indicator of population and trends. In 1990, 70 deer were taken here by hunters. In 2012, with fewer hunters in the town, 525 were “harvested,” the planner reported to the board. Reports of deer-vehicle collisions numbered 25 in 2000 and 108 in 2011.

    But, she said, the “primary indicator in our town is that our biodiversity has really suffered,” with the middle layer of vegetation in woodlands and in neighborhoods decimated by browsing deer. “In addition to young trees, we have lost wildflowers,” she said. In a PowerPoint presentation, Ms. Wolffsohn presented photos showing the evidence of deer overbrowsing and its increasing effect over the years on the woods understory.

    “I think we know that it’s flawed,” said Councilman Peter Van Scoyoc of the survey’s number. “Between the automobile strikes and the deer take, we have completely wiped out the population on an annual basis . . . I don’t believe we can obtain empirical data about the number of deer. At best we could look at other methodologies.”

    While an aerial survey is only just that — a survey, not a count — Ms. Wolffsohn said that other, more expensive, efforts may get the town closer to an actual count, or at least collect population data in a way that the margin of error can be calculated, and true numbers extrapolated.

    But, she suggested, pinning down the exact number of deer here may not be a key objective, as the evidence of deer overpopulation is clear.

    “I’m just saying, we had a plan that was going to be so scientific, and now we’re just saying let’s throw out the science,” Ms. Quigley said. “There’s something so fundamentally flawed with getting a scientific study and then throwing it out. . . . My point is, we’ve spent $13,000 on some expert. If we are going to be basing a plan on data, then the data we have doesn’t really support the plan.”

    “I mean, isn’t history replete with examples of people taking action foolishly?”

    The draft deer management plan, Ms. Wolffsohn said, “is not a plan based on that survey. It’s a comprehensive plan that gives us options on what to do.”

    Terry O’Riordan of the East Hampton Sportsmen’s Alliance applauded the board for its efforts to adopt a deer management plan. “The method . . . of the survey was not supposed to give you a finite number of deer,” he said. Of the 877 counted, he said, “Perhaps adding a zero to that number might be more of what we expected.”

    Both he and Councilman Van Scoyoc described how, in one location or short period of time, they had seen 80 to 100 deer. “Do you think I saw about 10 percent of the deer in the Town of East Hampton?” Mr. O’Riordan asked. “No,” he answered himself.

    Ms. Wolffsohn, he said, was “100-percent accurate” in her description of the way deer have decimated the forest understory.

    The Sportsmen’s Alliance, he said, believes the management plan “has merit,” and that the board should “approve it and then adapt it accordingly.” Taking action will help address a problem that “we know is out of control because of the physical evidence that we have available to us.”

    The deer distribution information provided by the survey is helpful, said Mr. O’Riordan. “It shows that we need to have more private property involvement in hunting.”

    Zachary Cohen, chairman of the town nature preserve committee, urged the board to organize a program through which homeowners could authorize hunting near their lots. He also suggested fencing in several wooded areas to observe undergrowth there in the absence of browsing deer, in contrast to surrounding areas.

    “A lot of deer management takes what we might consider anecdotal evidence,” he said. Mr. O’ Riordan agreed. Rather than counting deer before and after management efforts, including, potentially, a cull, to see if the efforts are effective, “we may have to use barometers here to get to the management,” he said. For instance, he said, after the town undertakes projects to get the herd under control, if the woods outside a fenced-in area then begin to resemble the fenced-in vegetation, “you could start to back off.”

    “I will say that the survey was really disappointing,” Councilwoman Sylvia Overby said. But, she said, Ms. Wolffsohn’s presentation was helpful. “The environmental damage, the destruction that we’re seeing, just doesn’t jibe.”

    “In hindsight, we shouldn’t have spent the money,” she added.

    “We were going to refer to a document that’s saying, okay, Dominick, you want to cull, you can kill this many. Should we discount this by 80 percent?” asked Mr. Wilkinson.

    A survey, regardless of the results, is a required prerequisite for a culling program, Mr. Stanzione noted.

    “Despite the results . . . we still need to reduce our deer population to restore our biodiversity, reduce vehicle collisions, and, hopefully, reduce tick-borne diseases,” said Ms. Wolffsohn.