Hundreds of geese honked emphatic objections as two Cornell researchers chased the flocks with an assortment of creative avian-repelling devices including a remote-controlled monster truck, lasers, a drone and firecrackers known as “bird bangers.”

The two researchers spent last summer harassing Canada geese in Stewart Park to determine the most effective way to reverse the birds’ annexation of the green, which is often littered with pounds of feces and occupied by close to 500 geese.

“Over recent years, there has been an issue with human-goose conflicts in the park, both from direct contact, and the feces that the geese leave behind,” wrote Prof. Paul Curtis, natural resources, and his advisee Heidi Henrichs grad, in the study released last week.

Rick Manning, executive director of Friends of Stewart Park, a nonprofit dedicated to maintaining and rehabilitating the park, said his organization has ambitious goals to fix old buildings and fund a new playground, but said he continues to hear concerns about goose feces.

“The funny thing is that with all of our grand plans, the one thing people keep talking about is the goose poop,” he said. “They’re cool birds. It’s not like people don’t like them — they just really don’t like the goose poop, and there’s a lot of it.”

Canada geese have become such a nuisance that the New York Department of Environmental Conservation wants to cut the number of geese in the state by more than half, from a current estimate of 200,000 to 85,000.

Hazing is part of a three-pronged approach initiated by Ithaca’s Geese Working Group to manage the birds. The working group, chaired by Fifth Ward Alderperson Josephine Martell grad, has been laboring for over a year to rid Stewart Park of goose feces and sometimes-aggressive geese.

“When the geese have young, I guess people get too close to the goslings, and the geese will act very aggressive, but only when threatened and only when they have goslings,” Martell said, adding that she is not aware of any injuries caused by geese at the park.

Common Council instituted a ban on feeding Stewart Park geese, part of the working group’s strategy, in May. The other two methods — keeping goose eggs from hatching and finding ways to safely harass the geese — are still under review. The study, a collaboration between the City of Ithaca, New York DEC and Cornell, adds a wealth of data to the discussions of how to move forward.

The most effective method of getting the geese out of the park, Henrichs said, was chasing the flocks into the water using a remote-controlled monster truck and then firing “bird bangers” — which produce either a loud bang or a screeching noise — from a pistol to spook the birds off of Cayuga Lake’s shores.

But despite the bird bangers’ effectiveness, the tools may not be a realistic option for regular use. The researchers were compelled to alert local police that they were using the pistol during the study in case anyone thought it was a gun, and said the noise could be even more disruptive than the geese.

“If we did [use] firecrackers every morning for two months, I wonder how many calls we’d get from West Hill,” said Jeanne Grace, the city forester, at the Parks Commission meeting on Tuesday.

Stewart Park’s unique geography was also an obstacle for the researchers, who quickly realized there were places the geese could hide where the drone and truck could not invade.

“The real challenge is the geography … with the inlets and the canals,” Curtis said. “That’s the one thing that we couldn’t do, is break the site fidelity of the geese. They always had a spot where we couldn’t chase them or haze them.”

Surprising to Curtis was the ineffectiveness of the $400 drone, which was difficult to maneuver into tight spaces and, while aggravating to the geese, rarely forced them to take flight. The researchers even dangled a small weight from the bottom of the drone with string, but to no avail.

“Rather than fly and scatter, what they did is huddle in a defensive group and look up and all honked at this thing,” he said.

The researchers also counted the number of “fresh fecal deposits” along four, 100-meter lines, counting up to 125 fresh feces in a single square meter. In addition to the annoyance feces pose, there is also a minor health risk, Curtis said.

“People don’t like sliding around in feces or feces all over your shoes,” he said. “We do know from research, though, that goose feces do carry salmonella and other types of bacteria that can lead to health issues. … But there’s no specific issue I can point to and say this person got sick from goose feces.”

Henrichs, who called studying birds one of her great passions, said some of her friends have been “off put” by the idea that she spent her summer around goose feces, but she made it clear that she never had to touch or smell — just count. Flying the quadcopter and steering the monster truck, she added, was a blast, even if she felt a bit silly at times.

“It was absolutely fun — it was great,” said Henrichs, who drove to the park multiple times each day toward the end of the study. “I also felt like a little 12-year-old boy. I spent my summer playing with drones and remote-controlled toys and fireworks.”

Henrichs also utilized bird lasers, which are aimed near the geese to trick them into thinking something is in the water, but said they were largely ineffective and can only be used at dusk or dawn and when the park is empty.

The researchers concluded that the density of goose feces and the number of geese declined over the course of the study, but the report notes that it is “difficult to determine whether the use of our deterrents decreased the goose population more than would have happened with normal seasonal movements after the molt.”

Stewart Park remains a “perfect habitat for geese,” Manning said, but it hasn’t always been overrun by the migratory birds.

Ithacans placed decoy birds around a pond in Stewart Park in the 1920s to attract waterfowl for hunting, but as hunting declined because of regulation and declining interest, the population “exploded” in the last two decades, Manning said.

“Maybe you could use these goofy ideas” to reduce the population, Manning said of the researchers’ methods. “It would be a fun summer job for a high school kid, driving around a remote car.”

Despite the limited success of some methods and the researchers’ desire to use a control group in future studies, the report serves as a much-needed baseline for city officials as they mull over what can be done to remove geese from Stewart Park without resorting to lethal methods.

“We don’t have to remove the population from Stewart Park, we just need to bring it down to a level that is acceptable for people using Stewart Park,” Martell said. “It’s like finding that sweet spot where they are no longer an egregious nuisance.”

The researchers believe that there are only about a dozen nests in the park, and Martell said she and others are trying to initiate an egg treatment program, in which oil is rubbed on goose eggs to deprive the embryos of oxygen and keep them from developing.

Martell, who is working toward a PhD at Cornell’s Department of Natural Resources, said the city will review “all options” for removing the geese, but that she would strongly prefer a non-lethal management program.

In the study, Curtis and Henrichs write that “nearly all the geese in Stewart Park could be captured in a single round-up effort” and that killing them could reduce the number of geese, feces and feathers “for several years.”

“If the goal is really to reduce bird numbers and conflicts with people, a roundup is definitely the way to go,” Curtis said. “But with any pool, you have to consider the social aspects, and right now, the stakeholders in Ithaca are not ready to try lethal management.”