Deep in the densely populated suburban grid linking Baltimore and Washington, a national treasure is hidden.
It is the U.S. Fish and Wildlife Service's Patuxent Research Refuge and it is preparing to celebrate the 100th anniversary of the National Wildlife Refuge System -- a collection of more than 500 refuges encompassing more than 94 million acres in all 50 states.
After years of focusing on fences to protect the refuges and the wildlife that live in them, the system is taking steps to become less hidden and more appreciated.
Last weekend, Patuxent held a festival that included animal demonstrations, guided hikes, children's activities and behind-the-scenes tours to attract visitors and show off what the refuge has to offer.
"For a long time, our attitude was if we only keep people out, we can do our job of protecting wildlife," said Dan Ashe, chief of the National Wildlife Refuge System. But now the organization realizes that "we need people to understand [our work]. We need to get them to come to the refuge, to see what we do and see the benefits to wildlife preservation."
Just a few miles from the high-speed traffic of Interstate 95, Patuxent vividly illustrates the importance of refuges in the nation's conservation history.
Its 13,000 acres, crossed by the Patuxent and Little Patuxent rivers, represent one of the largest uninterrupted patches of greenery remaining in the mid-Atlantic area. Its pine forests and more than 50 artificial ponds provide an important rest area for millions of migrating birds.
Beyond that, the Patuxent refuge is one of the country's most important wildlife research centers. The only refuge founded with a research mission, it produced many of the contaminant studies that inspired Silent Spring, Rachel Carson's landmark environmental anthem. Eventually, work at Patuxent led to a ban on DDT and other dangerous pesticides in the 1970s.
Here endangered bald eagles and whooping cranes have been bred for reintroduction into the wild. In the spring, for the first time in decades, a chick reached fledgling age in the wild after being born to two Patuxent-raised whooping cranes. Another programs using glider planes is teaching the cranes to migrate again.
Also at Patuxent, the Bird Banding Laboratory is marking a century of tracking birds with metal leg bands, a practice that has improved understanding of dozens of critically endangered species.
Since 1998, Patuxent's research programs have been directed by the U.S. Geological Survey, although the refuge continues to be managed by the Fish and Wildlife Service. But the lines are blurred as scientists continue to do research at forest, meadow and wetland sites hidden in the heart of the refuge.
Other areas are open to visitors who know where to look. An information center introduces the public to the refuge system and its accomplishments across the country. It is also used to train teachers about ecology and to sponsor class trips.
"The original purpose of the refuge is to promote wildlife," said Brad Knudsen, refuge manager. "We can't allow anything that conflicts with that purpose."
But human activities do fit into the equation, particularly after the refuge mission was more clearly defined by 1997's federal Refuge Improvement Act. Knudsen said, "Once we've taken care of the wildlife, there are six wildlife-dependent public uses we try to accommodate." They include wildlife observation, photography, education for schoolchildren, interpretation for visitors, hunting and fishing.
Hiking, bicycling, horseback riding, bird watching and other wildlife viewing activities are also welcome in certain parts of the Patuxent refuge
At Patuxent last year, more than 200,000 visitors viewed the center's multimedia wildlife exhibits and walked to wildlife observation sites.
It is a popular passion. A national survey by the Fish and Wildlife Service found 82 million U.S. residents over the age of 16 enjoyed a wildlife activity such as hunting, fishing, and wildlife-watching in 2001.
The numbers are preliminary, but the service believes more than a million Maryland residents and more than 500,000 nonresidents enjoyed wildlife-watching in the state in 2001. Participants spent close to $1.4 million in Maryland to support the activity, the study said.
Nationally, wildlife-watching increased 5 percent over four years, though numbers overall are down compared with statistics from 1991.
Wildlife advocates question some public uses of Patuxent and other refuges -- particularly hunting, fishing and trapping.
"It certainly would come as a surprise to most people to learn that [this] taxpayer-funded refuge for wildlife is in fact no refuge," said Jeff Leitner, program manager for the Fund for Wildlife, a Washington-based environmental advocacy group.
But the Fish and Wildlife Service defends hunting and fishing as appropriate activities that, in monitored situations, are compatible with conservation and in some cases, serve to control animal populations.
Deer, for example, have no natural predators in the refuges, said Brad Knudsen, the Patuxent manager, and when there are too many in the forest they can eat important plants and destroy habitats for birds and smaller animals.
Some things are not allowed at Patuxent at all, including picnicking, swimming, rafting and boating.
"It is a balancing act," Knudsen said. "There will always be people who feel we haven't accommodated them."
That balance is sought at 535 refuges across the country, from the half-acre Mille Lacs National Wildlife Refuge in Minnesota to the 19.2 million-acre Arctic National Wildlife Refuge in Alaska.
The first refuge was a 3-acre island in Florida's Indian River Lagoon, set aside in 1903 by President Theodore Roosevelt as a safe place for pelicans.
The Patuxent refuge began in 1936 with 2,670 acres of federal land and acquired parcels over the years, including 1,250 acres from the U.S. Department of Agriculture in 1975 and 7,600 acres from Fort Meade in 1991.
Occasionally, someone will find a shell or piece of equipment on the former military land that requires removal -- but no one has ever been injured, Knudsen said.