BURLINGTON COUNTY, N.J. -- On a drawbridge spanning the Wading River in south Burlington County, two volunteers and a zoologist from the state's Division of Fish, Game and Wildlife searched the skies for bald eagles.
Armed with a spot scope and gloves to weather the cold, they arrived at 7 a.m. on a recent Sunday to record how many of the endangered birds they sighted. By 9 a.m., they had spotted three that had flown across the reedy marshes before disappearing into the pine canopy.
The New Jersey bald eagle population, nearly obliterated by the pesticide DDT in the early 1970s, is on the rise again, according to the state's Endangered and Nongame Species Program.
Twenty-two years ago, the program documented only six bald eagles. Last year, that number had reached 94.
The agency, which has conducted an annual survey of the birds since 1978, organized more than 150 volunteers over the weekend to execute this year's study.
"The information this provides us as a state agency -- we know what areas birds are feeding in and roosting in, so we can target those areas for conservation," said Eric Stiles, 29, a senior zoologist at the Division of Fish, Game and Wildlife and coordinator for the survey. "After we find them, then the real work begins."
The bald eagle population in the lower 48 states has rebounded from near extinction to about 2,600 nesting pairs, according to the federal Bureau of Land Management.
Although the federal government plans to rescind the bird's endangered-species status next year, New Jersey will keep the bald eagle on its endangered list, Stiles said.
Many of the birds found in New Jersey during the winter have migrated for the season from Canada and New England in search of more plentiful food and unfrozen lakes and streams. Although the midwinter population peaked three years ago at 176, Stiles attributed the recent drop-off to warmer weather, allowing the migratory birds to remain in their habitat.
The population inhabiting New Jersey year-round has also risen.
From 1986 to 1998, eagle pairs increased from one nest in Bear Swamp, Cumberland County, to 15 pairs.
Last year, according to state statistics, the population showed its strongest growth yet at 22 pairs -- including 19 in South Jersey. That rivals the number of nesting eagles seen in the state before World War II, when DDT came into popular use.
The pesticide, which weakened the eggshells of the bird's offspring, was banned throughout the United States in 1972, and the eagle has been slowly making a comeback.
But in New Jersey, the population increase is also attributed to an eagle reintroduction program in the 1980s and about 100 volunteers and landowners who find nests and guard them from disturbance. The birds are sensitive to human encroachment and will abandon their nests if bothered.
Rich Beck, a regional coordinator for this year's survey, volunteered to keep watch on a bald eagle nest in south Burlington County for two years in the mid-1990s. He worked with the private landowner, posting signs to keep people away, and observed the birds' comings and goings several times a week to make sure they remained undisturbed.
"Personally, I would only go out of my way for eagles," said Beck, 39, an environmental consultant who lives in Browns Mills and began bird watching for bald eagles in 1985.
"At the time I started, they were uncommon. They are a lot more common now."
The state established a bald eagle observation area on Stow Creek near the border of Salem and Cumberland counties to allow the public to observe a nest from a safe distance.