"It's the only way I can tell if the birds are great blue herons in their white phase or great egrets," she said, explaining that the birds had different colored feet.
Finally, one of the birds accommodated her, and she decided they were great egrets.
The egrets, which Koenig said probably had stopped at the swamp while passing through New Jersey, were only one of many plant and animal treasures that greeted two groups of hikers through the meadows and wetlands of the 89- acre Taylor Wildlife Preserve last weekend.
The tours were arranged by the state Natural Lands Trust as part of Environmental Education Week. They were designed to introduce the preserve to visitors interested in seeing an area that is home to more than 190 types of birds and animals and supports a wide variety of plant life.
The preserve is part of a farm that has been owned by the same family since 1720. In 1975, present owners Joseph and Sylvia Taylor donated a conservation easement to the trust to preserve it from development.
The trust, established in 1968 to conserve natural land through similar easements, now manages more than 3,500 acres throughout the state.
The Taylors still live on the farm, which is the only operating farm fronting on the Delaware River between Trenton and Camden. They organically farm 40 acres adjoining the preserve.
JoAnne Ruscio of the trust said she thought of the Taylor Wildlife Preserve as an oasis because of its beauty and location in the midst of a highly developed river town in South Jersey.
But it is an oasis the trust is having trouble telling people about.
Ruscio said that while she was turning people away from some of the nine tours at other preserves in the state this spring, very few people had signed up to view the Taylor preserve.
She hopes to find a way to let more people in South Jersey know about the Taylor preserve, and that it can be visited by walkers anytime or seen on future trust tours.
The group last weekend was made up of people who happened to be on a trust mailing list. David White of Edgewater Park and Jane Bourquin of Westmont, for instance, are volunteers at the Rancocas Nature Center.
Mickey and John Eichorn, who live near the Delaware in West Deptford, have been involved with the state because of environmental problems near their home.
And Stanley and Emma Yankauskas of Cinnaminson found out about it through Stanley's job as an engineer with the state Department of Environmental Protection.
All seemed enthusiastic as they spent almost two hours tramping about in wet and chilly weather.
Along the way they gazed at birds like the egrets and a pair of downy woodpeckers. They watched as Koenig identified plants such as multiflora roses, purple dead nettle, wild blackberries, wild mustard, skunk cabbage, poison ivy, and sassafras and sweet gum trees.
And they learned such tidbits as the fact that the leaves of the pepper plant can be used like hand soap and that in any given year you can expect to see 300 of the 420 species of birds that live in New Jersey.
"It's the first time we've ever done anything like this, but we're enjoying it," John Eichorn said.
Bourquin, who said she had visited the farm to buy organic produce in the summer, said it was also her first trip.
"I love it," she said, as she helped Koenig identify a fiddle fern. "I know I'll be back."
For Ruscio and Koenig, a naturalist who grew up in Iowa and has lived in New Jersey less than two years, the small group was a mixed blessing.
They said that while they wanted people to know about the preserve, it could be ruined if too many people visited it and misused it.
"If it weren't for places like this and the Pine Barrens, I would go nuts here," Koenig said. "It's nice to find a little refuge in the middle of all the craziness."