CITY HALL -- There is now proof that Staten Island's white-tailed herd is much larger than the aerial surveys have estimated.

There are likely well over 1,600 deer living in the borough now -- more than three times the city's last count and a 6,680 percent increase in the herd since 2008.

Wildlife biologists believe bucks make up about 40 percent of suburban deer herds that aren't hunted.

The city has performed vasectomies on 651 Staten Island bucks through Wednesday, so the herd likely has a minimum of 1,628 deer.

And the total population is probably much larger than that -- Parks Department contractor White Buffalo is expected to continue performing surgeries on male deer until the end of March.

Only 527 deer were found on Staten Island during the city's latest aerial survey of the herd -- 236 less than a count three years ago and well below what the city expected.

The city only looked for deer on Island parkland in 2014, while the most recent survey in February 2016 was of the whole borough.

Officials said fewer deer could have been found last year because the survey was done during warmer, less cloudy weather than in 2014. Infrared picks up less on clear days and deer may have been more skittish in higher temperatures.

"There's nothing to indicate that the population has declined -- we are confident that it doesn't mean that," Sarah Aucoin, Chief of Wildlife and Education at Parks, said last July. "What this means is we've got a minimum of 527 deer on the Island, but it's likely much higher."

A state Department of Environmental Conservation study from 2008 estimated the borough was home to roughly 24 deer. Wildlife experts speculated that the herd grew when deer swam across from New Jersey because of dwindling food sources and habitat loss.

VASECTOMY PLAN

An unrestrained and expanding deer herd can harm parks and private property, spread tick-borne illness and wander into roads more often, increasing the risk for deadly vehicle collisions.

Last fall, the White Buffalo began performing vasectomies on Staten Island bucks as a way to manage and cut down the herd.

The effort is expected to eventually reduce the herd 10 to 30 percent annually.

Some wildlife experts thought the plan won't work because the city is ignoring basic deer biology and conventional herd management practices.

The city believes the herd is now growing mostly through reproduction, not migration onto the Island. Sterilizing males instead of females is meant to be faster, cheaper and more humane.

HERD ESTIMATE COMING

White Buffalo is being paid $2 million this fiscal year for the work. The contract is for up to $3.3 million over a three year research study.

The company isn't just performing the vasectomies, but also tracking deer with ear tags, radio collars and trail cameras.

Forty-three bucks and 28 doe had radio collars as of Wednesday.

The city said on Tuesday that White Buffalo is reviewing the data they're collecting and plan to estimate Staten Island's deer population soon.

Last year's survey showed large concentrations of deer in the Greenbelt, most parks and along the West Shore. But many deer were also found in residential parts of the city.

Evidence of illegal deer hunting has been found in the Greenbelt and other borough parkland. Deer killed by cars and other causes have been discovered throughout Island parks too.

The city has euthanized five Staten Island deer that were injured during the vasectomy program as of Wednesday. This is required under the city's permit with the state.

This article was corrected to clarify that the vasectomy effort is expected to eventually reduce Staten Island's deer herd 10 to 30 percent annually, not 10 to 30 percent overall.