Tired of droppings from Canada geese mucking up their public golf course, park officials two years ago began shooting blanks into the air twice a day to scare away the more than 250 birds that had settled there a few years before. It worked.
But the frightened gaggle flew no farther than across the street to the Quaker school's 40-acre campus, where no amount of spooking has been able to get rid of them since. "They came to visit and said, 'My, isn't this lovely' and they just took over," Robersen said.
The Branta canadensis, the Canada goose, has taken over all over.
Its presence in the Northeast, including Philadelphia and surrounding suburban areas, has tripled in the last 30 years, according to Charles Strouphar, a waterfowl management assistant for the Pennsylvania Game
The Philadelphia area is part of the Atlantic Flyway, one of four flight paths traditionally used by the geese on their trek from Canada southward in October and back north again in March. One million populate the Atlantic Flyway.
Locally, that heightened presence has brought messy problems for joggers near the river and children at school, golfers and greenskeepers, suburbanites and farmers. "If they just didn't poop so much, they'd be great," said John Hoover, director of parks and recreation in Cheltenham Township, where geese descended on Conklin Pool in the off-season two years ago.
Township workers placed a network of string across the pool to frustrate the waterfowl and left it there for a few days. The birds took off and have not returned. "So tell them to keep the geese in Abington," he said.
String strategy eventually may be used at Abington Friends School, where Robersen said she "hollered for a whole year" to have the cafeteria staff and others stop feeding bread to the geese. Shooting guns, even blanks, into the air, was unacceptable to an institution dedicated to Quaker pacifism, but nothing short of that seemed to work.
"I can understand the teachers being concerned about the mess. On the other hand, I don't want to go into the air guns. This is a Quaker campus and I don't think air guns are appropriate here," she said.
So Robersen retreated to her basement and fashioned four life-size wooden decoys of the mute swan, a goose's natural enemy. The ruse worked for a while; the birds fled to Curtis Park in Cheltenham. Eventually, the birds figured out they had been had and back they came.
"They realized the swans didn't move quite enough. So they decided to make friends with them. Now, they all stand around together," Robersen said.
Meadowbrook Country Club in Abington Township took a less subtle approach. When about 100 geese took up residence there a few years ago, groundskeepers drove around in tractors to scare them off. According to Herman Reibstein, pro shop manager, the geese stayed away for a few days and then came back.
"They're a nuisance. They mess up the greens," he said.
Officials at Abington Friends School are considering tying weights on the end of helium-filled balloons on which scary faces have been painted and placing the balloons around the pond. Or, Robersen said, they might have to drain the pond or surround it with rocks to discourage the geese from landing.
Some of the geese land in the darnedest spots.
At the Axewood office building in Ambler, for example, a mother goose laid eight large white eggs in a nest just outside the front door. She snaps and hisses and flaps her wings at office workers who try to get past her, but the human side of the turf battle bears her no ill will. Deborah Quinley, a legal secretary who works in the building, said co-workers were feeding the goose vegetables and taking up a collection to buy her goslings a wading pool.
"We feel so bad. There's no water around here for when the babies are hatched," she said.
There is undoubtedly some nearby, however, for water is what draws the Canada goose. On the banks of the Schuylkill in Philadelphia, the goose population has grown from two to about 2,000 in the last 20 years, according to Dick Nicolai, Fairmount Park Commission spokesman.
Park officials have done nothing about it beyond discouraging the public
from feeding the birds. Giving handouts is detrimental to their natural foraging habits, Nicolai said, and however well-meaning, the handouts sometimes end badly. Food thrown on the ground can spoil; occasionally, autopsies have shown that geese died of botulism.
"We've thought (we'd) better consult with experts in the very near future to consider thinning the population out or decreasing its progression somehow through birth control. It's (the number of geese) is on the verge of becoming a problem," Nicolai said.
But any action against the long-necked, web-footed fowl, one of the most beloved in the world of common hooters and honkers, is likely to provoke the public. Despite the "Canada" in its name, the Canada goose - also known as the Canadian honker or the honker goose - is sometimes promoted as a better choice for a national bird than the bald eagle.
To admirers, it is a beautiful sight to watch hundreds of Canada geese in stark V-formation in the October sky. To admirers, the cacophony of the distant honking of the geese is a soothing sound.
But even goose-lovers have learned to watch their step.
"They add a nice touch to the park but, well, you know. You've got to watch where you walk," said Nicolai.
There are 11 subspecies of Canada goose ranging from two pounds to 20 pounds. Domesticated, some can live as long as 40 years, though most live about half that long. They are fiercely protective, monogamous and smart.
And distinctive in markings. Each has a white belly, a grayish-brown torso with a white band across the rump, a black tail, black feet and beak, and a black head with white cheek patches.
They are known for their graceful flight, their dramatic take-offs and landings and their tremendous flying stamina. According to Strouphar, who works at Middle Creek Wildlife Management Area in Lancaster County, Canada geese fly up to 350 miles at a time before coming down to eat. They always fly in their familiar V-formation to cut wind resistance for each other.
Airline pilots have reported seeing them at altitudes of more than 12,000 feet.
But in the last three decades, experts say, the birds' winter journeys south to places such as North and South Carolina and Georgia have gotten shorter and shorter, a tendency known as "shortstopping."
Fully 70 percent of the geese that used to fly south in the Atlantic Flyway now end up spending the winter in Pennsylvania, Maryland, Delaware and points even farther north.
The major reason for this, according to Strouphar, is that technological advances have allowed farmers in the North to raise corn and other crops to maturity where they could not before. Instead of bare, hard fields, Canada geese now find a gleaner's delight in fields covered with harvest leftovers.
And there are more fields in which to forage. Around the Finger Lakes in New York State, for example, acreage devoted to corn production has tripled in the last seven years, according to that state's Department of Agriculture.
"It's not the cold weather that drives geese south, it's food. If food's available, they don't go," Strouphar said.
Richard Malecki, assistant leader of the New York Cooperative Fish and Wildlife Research Unit at Cornell University in Ithaca, N.Y., suggested other reasons for "shortstopping" by the Canada geese.
Geese that fly far south for the winter subject themselves to more areas open for hunting than in the North, Malecki said, while the number of wildlife refuge areas in the North has increased. "When all their winter needs are met, they don't feel the need to go further."
A goose at Abington Friends School has a neck band identifying it as one of 23,000 participants in Malecki's research project on migration patterns and survival rates of Canada geese. Increasingly, he said, these geese are being found in the corridor from Boston to Baltimore.
"Really the only way to decrease growth is to lower the survival rate of the adult geese. In other words, harvest them, hunt them, and that's not allowed in developed areas," Malecki said.
Short of that, "there isn't a whole lot you can do," he said.
But Susan R. Forster, Abington's parks and recreation superintendent, is certainly trying.
At Alverthorpe Park, township workers first tried using styrofoam swan decoys, but like their wooden counterparts at the Quaker school, the phony fowls fooled no one. So every morning and evening, as the ritual has gone for almost two years, someone loads a shotgun with blanks, steps outside and shoots it into the air.
This has kept away all but about 20 birds and has virtually salvaged the regular and miniature golf courses and the five-acre lake, Forster said.
According to waterfowl experts, other ways to discourage the geese include building a chicken-wire fence around the edge of a pond, which would force the birds to hop over it to get to the water, filling a weather balloon with helium and sticking it to a post or painting five-gallon buckets a fluorescent orange or some other unnatural color.
"They're not colorblind. Those buckets will bother them," Strouphar said.
Edwin Butler, who monitors Canada geese for the U.S. Department of Agriculture in New Jersey, suggested brightly colored flags placed around the pond. "The more things you do, the more likely you are to succeed," he said.
In the past, birds were sometimes captured during their molting season in late June and July, when they cannot fly for a whole month, and transported to southern states. But, Butler said, that is expensive, the southern states do not want the geese anymore "and let's face it. I've had birds relocated and the next day, the people call up and say they're back," he said.
Even the experts are sometimes stymied.
In Chester County, geese have stripped a 15-acre barley field at the New Bolton Center in Kennett Square, which is the large-animal campus of the University of Pennsylvania School of Veterinary Medicine. The Penn staff is stumped and, like Abington Friends School, hesitant to take strong measures.
"Winter grains are planted in the fall so they're small and tender and kind of succulent through the winter. The geese love the small grains. Eventually, that field wasn't worth salvaging so we plowed it under," said associate dean Richard McFeely.
In addition to losing the barley crop and the straw that goes with it, McFeely said the school has other goose-related concerns. Soil is eroding from the bare field into a stream and because of goose droppings, the campus fishing pond is "just not pleasant to be around anymore."
"And we have some concern that waterfowl may be a reservoir for disease," he said.
Droppings from migrating waterfowl contain disease-carrying spores that in mild forms can produce flu-like symptoms, and in extreme forms can cause pneumonia or hepatitis. But the risk to the public is minimal, according to Lawrence Glickman, associate professor of epidemiology and public health at the Penn veterinary campus in Philadelphia.
"People can be affected if the soil, where these spores are found, dries up or you get a drought and the wind kicks up and you inhale the spores" but geese are far less likely to cause problems for people than pigeons roosting in city buildings, he said.
Robert Sharrar of the Philadelphia Health Department agreed. The danger to humans is "minimal to non-existent. (Goose droppings) are just a nuisance," he said.
At Penn's Kennett Square campus, the nuisance is growing at an astounding rate. In 10 years, the goose population there has exploded from "a very few to thousands. What can we do? We're kind of a wildlife sanctuary here. We don't permit hunting but they are certainly a mess," McFeely said.
"We're sort of in a quandary. On the other hand, they're taking advantage of our hospitality," added Glickman.
Like Penn officials, Abington Friends School's Robersen said she was trying to come up with a solution to the problem that would please everyone. "We're very much into environmental protection, so although we'd really like them to migrate, we will not harm them to get them to move," she said. "If we do get rid of them, it has to be a natural response of the geese to what we do."
But so far, Canada's gift to Abington is doing what comes naturally. They are making themselves right at home.