He's killed thousands of deer all over the world. Now, he's been hired by the city to help manage Staten Island's exploding deer population. His solution: vasectomies. NY1's Amanda Farinacci filed the following report.

It's a telltale sign of deer: hoof marks. And on a muggy summer morning in Conference House Park, it didn't take us long to find the buck himself, the animal unfazed by people or our camera.

"There's a lot of deer on Staten Island. There's no doubt," said wildlife biologist Tony DeNicola.

An aerial survey by the city two years ago counted 763 deer in the borough, though some experts place that number at closer to 1,000, an exponential increase from the 24 deer counted in 2008.

The animals are creating traffic hazards and increasing the threat of ticks and Lyme disease.

After hashing out alternatives, the city hired DeNicola to bring the population down. His solution: birth control. More specifically, vasectomies. DeNicola says it's surprisingly easy and can be done much faster than sterilizing females.  

"I can go to that male in the field and do a very minor procedure and then leave, versus trying to transport all these animals, like we do with the females, and bring them to a central location," he said. "So it offers us a degree of versatility and efficiency."

Over the past two weeks, DeNicola has walked some 20 square miles of green space in the borough surveying the deer problem so he can put the finishing touches on his control plan.

He says Conference House Park, a stone's throw from New Jersey where some deer came from, has a high concentration of deer.

He shows us the signs of their presence, like a damaged tree trunk. The biologist says a buck likely rubbed its heads against it to mark its territory. And a lack of greenery, from the ground to a height of about four feet, peak grazing height for the animals.

The city's plan still needs approval from the state's Department of Environmental Conservation, which monitors wildlife. It's hoping to get the go ahead in the coming weeks so it can begin sterilizations ahead of the fall rutting season.