Some steal into neighborhood parks under cover of darkness, seeking to dispose of unwanted waterfowl. Others brazenly do the deed in the light of day.
Call them duck dumpers.
"We just stopped a guy last month who had 10 ducks in the back of his car," said Deborah Yeater, superintendent of Lake Waterford Park in Pasadena.
While that man apparently did not surreptitiously return to deposit the birds at night, other people have done that, helping to fill parks around the state with an assortment of abandoned pet fowl: ducks, geese, even chickens.
Twelve-acre Lake Waterford, for example, is home to 35 geese and 75 ducks -- a United Nations of domestic breeds -- and a watering hole for about 100 transient mallards.
The situation there is similar to that in community ponds all over the state, officials said.
"None of the ducks and geese that are here were born here," Ms. Yeater said. "They've all been dropped here," he said.
"It's a real chronic problem," said Marilyn Mause, Maryland Department of Natural Resources regional wildlife manager for Central Maryland.
"You pretty much go to any community pond and you can see non-native ducks," said Clifton Horton, DNR district wildlife manager for Montgomery and Howard counties.
State regulations ban the release into the wild of any nonnative animal that may harm native animals or plants. The maximum fine for a first offense is a $1,500 fine per animal released, but officials said they cannot recall anyone being fined for dumping domesticated waterfowl.
Kenneth D'Loughy, DNR wildlife manager for Southern Maryland, says well-intentioned people assume that if they bring the fowl to a place that has water it will live happily ever after. They often don't.
Just ask Terry Moritz and Donna Jones, two women from Pasadena who often come to the aid of birds in distress. Both have taken formal courses in caring for injured wildlife.
On a wind-whipped Sunday two weeks ago, the women made three trips to Friendship Park in Glen Burnie, where the pond was frozen over and the birds needed water. The third trip made the two women scream in anger.
"I found skate tracks on the ice that stopped in a bloody mess," Ms. Moritz said.
Someone had skated into a domesticated duck, piercing its lung, leaving the bird to die. The skaters, whom the women had beseeched at midday to avoid birds at the pond, were gone.
Still there were the eight ducks, one goose and two bantam chickens the women came to the pond to help -- all birds that could not fly, all abandoned pets that should not have been there in the first place.
The women took six ducks and the goose to Lake Waterford Park for the winter.
They took an injured Pekin duck to a veterinarian who operated and stitched up its chest. The bird is recuperating at Ms. Moritz's home, where she gives it antibiotics every few hours, changes its bedding, feeds it and -- because its breast feathers were shaved for surgery -- keeps it out of drafts.
"I will try to find a home for him," she said. "Actually, he is a very affectionate duck. He is a very obvious pet."
Another of the rescued ducks came home with Ms. Moritz as well -- a duckling so young it had a peep-like voice but had yet to grow its oiled winter feathers. "So it's obvious someone dumped that one," Ms. Jones said.
"It's also obvious somebody dumped the chickens because there is no way chickens would be there on their own," she said. The chickens, unable to stay warm outdoors without huddling among the better-insulated ducks, are staying with Ms. Moritz while she looks for homes for them, too.
It's not easy. Wildlife sanctuaries prefer wild animals, and animal shelters are geared toward placing furry pets.
The situation is complicated by ambiguous regulations governing their sale and by whether they are covered by local animal control ordinances.
The domesticated birds do not belong in the wild. Despite their down coats, domesticated fowl often cannot survive a winter. They are at the mercy of people for food, and they can't fly away when their pond freezes over. Even those that are able to fly don't know where to go or what environment to seek because they are accustomed to quarters with food, shelter and water.
The birds often become targets for roving dogs, snapping turtles, hawks, even each other. A lone newcomer to an established flock of fowl can get pecked to death by the welcoming committee.
Anne Arundel County spends as much as $1,000 each winter on corn to feed the birds in Lake Waterford Park, Ms. Yeater said.
Year round, park visitors bring them bread, seeds and the like. In warm weather hungry birds eat lakeside vegetation, leaving bare spots by the shore.
The fowl are an attraction, but the park can't support any more, Ms. Yeater said. About a decade ago, the population had gotten so large it had to be thinned out by taking fowl to Eastern Shore farms and water treatment plants throughout the region.
Waterfowl from other ponds have been relocated, often to the Potomac River, because those ponds could no longer support the burgeoning population.
Overpopulation is only part of the problem.
Domesticated fowl can harbor diseases that devastate wild populations.
Pekins, derived from mallards, can carry the virus that causes deadly duck plague. Atlantic Coast native black ducks and migratory pintails that pass part of the winter in the region are highly susceptible to it. People cannot contract it.
Every spring, duck plague hits somewhere in the state, often in backyard farm ponds, and flocks of fowl must be killed to prevent migratory birds that stop there from contracting the disease and infecting birds everywhere they travel, said Bill Harvey, a DNR waterfowl project manager.
Muscovy ducks, another farm breed, are often the first to die. That was the case on Stoney Creek in Anne Arundel County in 1992, when DNR officials killed some 50 domesticated fowl.
About four years ago, DNR killed several hundred ducks on Bear Creek near Dundalk, after the disease turned up there, said Ms. Mause. Officials suspected the disease was spread by domesticated fowl dumped there.
Similarly, about four years ago, all waterfowl at Allen Pond in Bowie were destroyed and the pond quarantined after the discovery of duck plague.
Domesticated waterfowl can also carry avian influenza and avian botulism, a threat to the Delmarva poultry industry.
People who feed the waterfowl may kill them with kindness. Some fowl get so plump that even though they could fly, they cannot lift far off the ground.
Two years ago, a motorist driving near Harford County's Bynum Run Park -- another popular place to abandon domesticated waterfowl -- had his car windshield shattered by a fat goose, Ms. Mause said. State highway crews commonly find dead fowl on the roadside.
The birds may also become more susceptible to disease if they come to rely on stale bread and other handouts. Fowl need a varied diet to stay healthy.
Fowl droppings can contain salmonella, and people -- especially children who are more likely to stick their fingers in their mouths -- can get ill from that, said Ms. Mause. The droppings also attract rats and contribute to the pollution of streams and the Chesapeake Bay.
Because they readily approach people, they are easy targets for abuse. Lansdowne's Hillcrest Park, Pikesville's Druid Ridge Cemetery, and Woodlawn Cemetery and Chapel Mausoleum are among the spots where DNR officials have responded to reports of waterfowl injured by people, Ms. Mause said.
Ms. Moritz and Ms. Jones have seen a lot of animals injured by people. Ms. Moritz says she spends about $2,500 a year of her own money to rescue abandoned waterfowl.
"You cannot just cut them loose," Ms. Jones said.