New York City gave 1,719 whitetail bucks on Staten Island the “big snip” the past four autumns as part of an 8-year, deer vasectomy experiment. The program hopes to reduce the herd population, Lyme disease, browse damage, and deer-vehicle collisions. It has cost the city $6.6 million so far.

As of early March—before coronavirus devastated NYC—City Hall remained committed to the vasectomy program, which began in 2016 as a 3-year, $3.3 million project. Wildlife experts opposed it publicly as early as 2015, warning that taxpayer money can’t buy alternative biology and happily-ever-after results.

The experts cited previous contraceptive experiments that targeted female deer, and generally failed to reduce herds and their problems. Vasectomies were previously tried in mostly futile, prohibitively expensive research to control free-ranging coyotes and feral cats, but might help reduce wild horse numbers.

As Cornell University ecologists predicted in 2015, original herd size estimates on Staten Island proved too low. Therefore, the program’s costs climbed to $4.1 million by the third year as contractors tranquilized, sterilized, and ear-tagged more bucks than planned. At $4.1 million, the mass vasectomies have cost $2,385 per buck. Even so, the city’s parks department extended the program in September 2019 for five years by agreeing to an additional $2.5 million for the contractor, White Buffalo, a nonprofit from Connecticut.

White Buffalo’s biologists and staffers shoot bucks with tranquilizer darts and perform the vasectomies. Dr. Anthony DeNicola, White Buffalo’s founder, estimated in March that his group has so far treated 95% of Staten Island’s bucks, but other experts still doubt the program can succeed.

Endless Costs
Prof. Paul Curtis at Cornell opposed the vasectomy plan before its launch, telling the Staten Island Advance newspaper in May 2016, “This plan has a very low likelihood of success.”

His doubts remain. “When they started, they thought they had about 1,000 does on Staten Island, and estimated they’d have to do vasectomies on 500 to 600 bucks,” Curtis told MeatEater in March. “They’ve already done more vasectomies [1,719] than the herd’s original population. That’s the problem with ‘open’ deer herds. You’ll never stop deer from immigrating or moving around. Controlling their numbers is like mowing your lawn. You can never quit once you start. You’ll always need annual maintenance budgets.”

Staten Island covers 60 square miles, and includes roughly half of NYC’s public parks. Those city, state, and federal parklands cover about 15 square miles. Staten Island has 475,000 residents, three times fewer than Manhattan, making it the least populated of NYC’s five boroughs. It’s also home to overabundant wild turkeys and feral cats.

Deer weren’t a problem until the past decade. Whitetails disappeared on Staten Island in the late 1800s and didn’t return until the mid-1990s. Biologists think they started their comeback by swimming narrower sections of Raritan Bay from New Jersey—roughly a 2-mile paddle—to find better, less-crowded habitat.

Aerial surveys estimated Staten Island held about 25 deer in 2008 and 800 in 2014. After White Buffalo performed vasectomies on 642 adult bucks and 78 buck fawns in late 2016, DeNicola used trail camera data from the borough’s parks to estimate the island’s herd at 2,050. Most Staten Island deer are likely born there, but biologists assume dispersing deer will always swim ashore each year as well.

Deer Politics
Annual swimmer numbers aren’t known, but they further complicate the controversial vasectomy program. James Oddo, Staten Island’s borough president, and Rep. Max Rose, Staten Island’s congressman, favor controlled hunts over vasectomies.

That pits them against Mayor Bill de Blasio, who backs the program even though it lacks an endgame. De Blasio dismissed Rose’s criticisms in January, telling the New York Post the vasectomy program is working: “It is the right way to go to get the job done, and you know the last thing we want to do is risk human life with the wrong kind of approach.”

De Blasio’s stance isn’t surprising. While running for mayor in 2013 he promised to end horse-drawn carriage service. That idea flopped, but in November 2019 he signed laws to prohibit horses from working when temperatures hit 80 degrees, or when temperatures and humidity total at least 150. De Blasio’s laws also criminalize taking pigeons or other birds from the wild, and ban sales of foie gras, a delicacy made from duck or goose livers after they’re fattened up, sometimes through forced feeding.

While signing those laws, de Blasio said: “If our relationship with animals isn’t right, then our relationship with the Earth isn’t right. If we allow cruelty in our midst, it’s a poison, it’s a cancer that grows.”

Professor Jim Tantillo at Cornell University questions the wisdom of spending millions on an inefficient, unpredictable effort.

“It’s an incredible waste of money, and it disappoints me that any municipality would take this on,” said Tantillo, who teaches students about environmental ethics and history, and the philosophy and morality of hunting. “The ethical question is whether these folks are being honest about their motives. They’re spending $6 million on deer vasectomies, which strikes me as an elaborate form of virtue-signaling that lets them tell everyone how much they care about animals.

“But they don’t talk about what they know from previous research: It could take 10 or 20 years to get where intensive culling would get them far faster and for far less money,” Tantillo continued. “Ultimately, the cost-benefit analysis matters. Are they really applying science to eventually reduce Lyme disease and deer-vehicle collisions, or are they just wasting money the city could use for school books, pothole repairs, and roof-patching on city buildings?”

Previous Research
Tantillo notes, for example, that Curtis and fellow Cornell researchers failed to reduce deer numbers on the university’s campus from 2007 to 2013 by sterilizing females. In that study, researchers “tied the tubes” of 74 does and surgically removed the ovaries of 19 does. They documented that 96% of the tubal ligations and 100% of the ovariectomies prevented pregnancy. Those efforts caused a 38% decline in adult does and 79% decrease in fawns.

But the buck population quickly jumped 873%. Curtis thinks bucks from surrounding areas flooded the campus because the 74 does with tubal ligations couldn’t get pregnant, and kept cycling into estrus every four weeks from late October through March. All those pheromones triggered futile, stressful breeding activity.

“We found 10% of the does completely depleted their bone-marrow fat,” Curtis said. “That kind of breeding activity would stress any doe on Staten Island, but it would kill a Northern forest doe in winter. It stresses bucks, too. Deer in the Adirondacks couldn’t survive without that bone marrow fat.”

Cornell’s researchers abandoned that experiment in 2013. Their 2016 report in the Wildlife Society Bulletin noted: “Given these new results, along with budget constraints, sterilization … efforts on Cornell University lands were discontinued in favor of lethal control methods in 2014.”

The ecologists didn’t make that decision overnight. Starting in autumn 2010, they struggled to capture the campus’s remaining untagged does, which had become wary and rarely showed themselves.

“Once you trap 65 to 70% of an area’s deer, they get smart,” Curtis said. “The only way you’ll get 90 or 95% of them is with tranquilizer darts, but that’s difficult, too. Deer learn what you’re driving and don’t let you get close. In our work at Fort Drum [northern New York], the only way we can get close enough is with a Prius. We rigged it to go dark and without the engine noise. I don’t know why, but deer never get wise to the Prius.”

Cornell University endorses the Northeast Section of the Wildlife Society’s 2016 position statement for managing chronic deer overabundance because lethal controls are faster, cheaper, and more effective. Curtis said Cornell reduced the campus’s herd 45% the first year (2014) by arrowing deer at night over bait; and catching them in “clover (net) traps,” and euthanizing them with a pneumatic bolt that penetrates the skull.

Counting Ghosts?
Meanwhile, it’s difficult to know with certainty how Staten Island’s deer herd is responding to the 1,719 vasectomies. White Buffalo performed 720 vasectomies in autumn/winter 2016, a combined 857 in 2017 and 2018, and 142 this past December and January.

DeNicola estimated the herd’s size at about 1,737 in June 2019, a drop of about 150 from his estimate of 1,884 in spring 2018. More recently, on March 25, he estimated the herd was down nearly 28% from about 2,050 deer in 2017, which means it would currently stand at about 1,500 deer.

But that’s roughly 220 fewer than the program’s total vasectomies. It’s conceivable that many deer died since 2016, given that they caused 279 vehicle collisions from 2017 to 2019, but those crashes weren’t restricted to bucks. It’s also likely more bucks moved to Staten Island in recent years, possibly lured by unbred does that kept cycling into estrus from late fall through winter, much like the unimpregnated Cornell does before them.

Besides, urban deer estimates routinely frustrate biologists. Dave Henderson has spent over 20 years managing whitetails in an 8.3-square-mile resort community on South Carolina’s Hilton Head Island. Before he started shooting in 2001, Henderson estimated the resort held 288 deer. His team shot 300 the first year, and 665 since.

“I was so shocked that first year that I felt the need to posthumously award unlucky deer No. 289 a certificate, as well as the hundreds of deer that followed,” Henderson said while reviewing his program at the 2017 Southeast Deer Study Group meeting.

Meanwhile, the stated goal of the NYC Parks Department is to perform vasectomies on 98% of Staten Island’s bucks. The department has given vasectomy percentages ranging from 92% in April 2017 to 98% in May 2019. DeNicola, who directs all media inquiries to the parks department, put the vasectomy rate at 95% on March 25.

Most biologists remain skeptical, noting the triple-digit vasectomy totals every year. Curtis and others think it’s likely impossible to capture and sterilize enough bucks to reduce the herd to tolerable, maintainable levels. Curtis said just one wary buck, given six months of access to hundreds of estrous females, could impregnate 20 to 40 does. Those does could then drop 20 to 80 fawns a few months later.

“That’s why all previous sterilization research targeted females,” Curtis said. “One buck can impregnate a lot of does.”

Urban Deer Zoos?
Dr. Grant Woods, owner and creator of “Growing Deer-TV” in southwestern Missouri, shares that skepticism. Woods has conducted research and contract deer removals at airports, golf courses, and other sites with problem deer. He has used bullets and tranquilizer darts extensively, and questions anyone who claims tranquilizer darts ensure safe, efficient, humane solutions.

“Deer run like a banshee when you dart them,” Woods said. “As the drug takes effect, they often stumble, stagger and fall at high speed. They’re not built to move sideways, so they can break legs, or tear muscles and ligaments as they stagger. And even though most darts have tracking devices and shouldn’t fall out of the deer’s hindquarter, they sometimes do. Or the transmitters just don’t work. Either way, it’s hard to find some deer. Nature programs on TV don’t show all those bumbles.”

Dr. Karl Malcolm, a frequent MeatEater Podcast guest and wildlife biologist with the U.S. Forest Service in Albuquerque, worries that Staten Island could turn deer into zoo animals.

“Deer evolved in nature to be productive, short-lived prey species,” Malcolm said. “They’ve always been hunted by humans and other predators. They’ve always died violent deaths. It’s a shame we’re so detached from nature’s realities that we’ll squander tax dollars on something with no realistic hope of solving problems our attitudes create.”

Feature image via Matt Hansen.