"Quiet, Hospital," says the sign on the door of a refurbished greenhouse where Thera te Boekhorst and her staff of 35 volunteers are at work saving the lives of hundreds of birds.
The large majority of the patients are migrating waterfowl that have become casualties of oil slicks in the heavily polluted North Sea.
The busy season for the Bird Hospital in Haarlem begins in November, when migrating birds like the guillemot leave their breeding grounds on the rocky shores of Scotland, Scandinavia and the northern Soviet Union to seek warmer climates in the south.
Hundreds of them never make it, ending up so mired in oil slicks that they die. But the 15-year-old Bird Hospital treats as many as 700 bird casualties at a time.
The hospital here is one of a dozen wild waterfowl treatment facilities that have proliferated in the Netherlands as part of Northern Europe's growing environmental movement.
Preserving wildlife is a much older tradition in this densely populated nation, whose Calvinist tradition mandates humane treatment for man and beast.
In fact, pets outnumber the Netherlands' 14.6 million people: 7.7 million pet birds, 3.6 million cats and dogs, 9.7 million aquarium fish, 1 million pet rodents and 300,000 horses and ponies, according to the pet food industry.
Although the Bird Hospital has a veterinarian on call to treat other wildlife casualties, such as traffic victims, oil slick victims are the specialty.
"Not a day passes without some new victims being brought in," Te Boekhorst said during her most recent emergency, an oil spill that hit the Dutch coast in mid-January.
More than 6,000 dead or dying birds washed up on Dutch beaches as a result of the spill, which the Dutch Traffic and Waterways Ministry said came from a Romanian tanker, the Borcea, whose fuel tank had apparently been damaged in an accident.
The oil damages a sea bird's natural protection from the elements by sticking its feathers together in bunches and leaving skin areas unprotected.
During the January emergency, the hospital, which is supported by donations, admitted at least 210 oil coated birds, mostly guillemots, a gull-like sea bird with a black back and white breast. It weighs about 2 pounds.
Other oil slick victims recently at the hospital included gulls, scoters and grebes.
Last year, about 75% of the oil slick patients admitted to the hospital died within weeks, mostly of pneumonia, Te Boekhorst said, noting that many birds also poison themselves by trying to peck the oil off their feathers.
After being admitted, the oil slick victims get a weeklong regimen of vitamins, antibiotics and sunflower oil, which acts as a laxative.
"Only when they've pulled through all that do we start washing them," Te Boekhorst said.
After washing with a special detergent, the birds are placed in an electrically heated cage designed by Te Boekhorst's husband, Frank. When dry, they are set swimming on an indoor pond until their feathers fall naturally back into place.
The winter oil slick victims are kept until the weather warms up in mid-February. Then they are driven to the nearby coastal town of Ijmuiden and released.
Last year, government inspectors registered 539 oil spills in the North Sea, according to the Traffic and Waterways Ministry. Te Boekhorst contends, however, that there are at least 15,000 incidents a year of small or large amounts of oil spilling into the ocean.
In most cases, the oil comes from tankers illegally washing out their holds into the sea before taking on new cargo.