An excessive number of ducks, geese and swans in Green Pond is elevating levels of fecal coliform bacteria, leading the state to close the entire pond to shellfishing last week.
The Massachusetts Division of Marine Fisheries ordered the Falmouth Department of Marine & Environmental Services to close 17 acres of Green Pond shellfish beds, R. Charles Martinsen III, the department’s deputy director and shellfish constable, said Tuesday, January 21.
State biologists reported to Mr. Martinsen that they observed residents feeding birds at the pond’s edge. Department of Natural Resources officers and Falmouth residents have also reported seeing hundreds of swans, ducks and geese densely congregated in the northern area of the pond.
“Several years ago, Falmouth Town Meeting heard an article related to a bylaw to help curtail feeding of the waterfowl. The measure failed, resulting in the town not having a bylaw in place,” Mr. Martinsen said. “If we can have some level of voluntary people willing to work with us, that will help us protect these resources in town that residents enjoy. The livelihoods of commercial fishermen depend on it.”
Assistant Town Manager Peter Johnson-Staub told selectmen recently that the issue of feeding birds was brought before Town Meeting about 20 years ago, adding that “it was not met with a warm response—the attempted regulation—but you may see that come around again.”
Last week and earlier this week, natural resources officers tried various methods to move the birds along, including using loud, blank shotgun rounds to flush the flocks and using skiffs to move the rafts of birds along.
Last week DNR officers fired two blank cartridges from the shoreline. The ducks and geese flew; however, not a single swan budged.
“We were out there Monday and Tuesday using blank shell casings and trying out an aerial device that makes a loud pop or explosion at a few different locations to see how it would work on ducks, swans and geese. The swans still don’t want to budge,” Mr. Martinsen said. “Swans don’t have predators, and they’re so acclimated to being around humans, they’re very brazen at this point.”
Feeding waterfowl is a biological, public health and environmental concern because it disrupts migration patterns, because one of the reasons for migration is for finding a new food supply. With a sustained artificial food supply from humans, waterfowl have less reason to migrate, Mr. Martinsen said.
Common food items fed to waterfowl, such as bread, corn and popcorn, have little to no nutritional value and may cause a nutritional imbalance directly resulting in metabolic bone diseases.
“One such metabolic bone disease is ‘angel wing,’ in which the wings become deformed because the carpal joint grows incorrectly, leading the wing to stick out from the bird’s body rather than to lie flush,” Mr. Martinsen said.
Artificial feeding encourages unnaturally large flocks to gather in one place, where the competition for food can cause unnecessary stress.
“This may weaken the birds and make them more susceptible to disease. Also, birds crowded into these areas are defecating in the same location where they are feeding,” Mr. Martinsen said. “Leftover food on land attracts rats and raccoons, which transmit diseases to humans.”
Excess nutrients in water bodies caused by large numbers of waterfowl droppings can result in algal blooms, and where waterfowl congregate to feed—as in this case—fecal coliform counts can reach levels that make the water unsuitable for recreational activities such as shellfishing and swimming.
There is an overall nitrogen problem in Falmouth’s water bodies, from septic systems and street runoff primarily. The birds, however, are the source of the elevated fecal coliform in Green Pond, Mr. Martinsen said.
“The high levels of fecal coliform this late in winter, when we have the least amount of people in the area around the pond, are absolutely tied to the birds, and my primary suspect for the large number of birds is that people are feeding them,” he said.
Other reasons for congregating birds are a period with low winds, as well as areas of open water in the midst of iced-over areas, Mr. Martinsen said.
“If birds find an area that ices up and a place adjacent to it that isn’t ice, they’ll fly into it because of open water,” he said. “Swans are basically unfazed by people and really loud noises. Black ducks and geese, however, need a little more confidence to hang out in an area. They like to be left alone, and no one is using the Green Harbor Motel right now in the area where they are right now.”
While the numbers of swan, geese and mallards have gone up on the Cape, the number of black ducks has gone down.
“Black ducks are natives that would winter here in salt marshes, and their populations have declined over the decades. Bay ducks like scaups, buffleheads and hooded mergansers are holding more steady than some of the other ocean-going ducks,” said Christopher Neill, a senior scientist at the Woods Hole Research Center and a member of the Falmouth Water Stewards.
Ducks contribute some nutrients to Falmouth ponds, but the larger problem comes from geese and swans.
Geese, being more terrestrial than aquatic swans, can concentrate their waste in a single area where they congregate, such as a playground, golf course or lawn, Dr. Neill said. They also bring some new nutrients from land into the water.
Swans, on the other hand, breed and winter in the estuary, eating submersed aquatic vegetation and recycling nutrients in the ecosystem.
“Swans like clear, shallow portions of the pond because they feed on the bottom, but they are pretty adaptable. They’re big and they don’t have a lot of predators. We are restricting their habitat, as some submersed aquatic vegetation has reduced because of nitrogen pollution.”
While dozens or hundreds of waterfowl gathering and remaining in a small area can negatively affect water quality, the much greater problem is wastewater from human sources, Dr. Neill said.