Their Pinelands habitat had been carefully prepared over more than 10 years. Controlled forest fires and tree-thinning opened up the landscape. And tall grasses filled in, providing cover for nests.

Then came the decisive moment on April 1 - the release of 80 northern bobwhite quail, captured in Georgia only about a day earlier.

They took flight from wooden boxes and began exploring an isolated Burlington County woodland that had not heard their distinctive calls for decades.

But would they adapt to the new environment? Would they reproduce and begin to restore the quail population in New Jersey?

Or would their numbers be thinned by the stress of their 15-hour trip to Chatsworth, disorientation in strange surroundings, and predators such as hawks and weasels?

The answer came over the last several days, as researchers checked on the small chicken-like birds - up close in the wild, and far off through the monitoring of radio-transmitting collars placed on them.

They heard the bobwhite calls again and found at least three nests. One had 14 eggs.

The quail "are calling like crazy," said John Parke, north region stewardship project director for New Jersey Audubon. "I can't express how joyous it is to hear them again in the Pinelands."

At least 45 of the 80 quail have survived the last 21/2 months. Most of the losses occurred in the first couple of weeks, when the birds were most vulnerable because of unfamiliarity with the terrain.

"It's awesome to know they are in the wild," Parke said. "It's a whole different world."

Fifty years ago, wild bobwhite quail were plentiful across parts of New Jersey. Coveys were common. Hunters flushed them out by the scores while walking through brushy fields.

But the chorus of bobwhite calls began disappearing along with the bird's habitat. Choked forests, paved roads, housing developments, herbicides, and pesticides destroyed the bird's food sources and nesting grounds.

The number of quail fell off so precipitously that - except for small pockets - they are close to extinction in New Jersey and Pennsylvania, and barely holding on in Delaware, wildlife ecologists say.

Only 600 wild quail were estimated to remain in the southern half of New Jersey, according to the last state survey in 2010 - and those numbers have not likely changed much, state officials said.

The April 1 release was part of a three-year collaborative conservation initiative involving cranberry grower Bill Haines of the Pine Island Cranberry Co., who provided his land for the project; certified forester Bob Williams of Pine Creek Forestry, who manages forests on Haines' 14,000-acre property; New Jersey Audubon, which has overseen the quail project; the Tall Timbers Research and Land Conservancy, which collected the birds; the University of Delaware; New Jersey Fish and Wildlife Division officials; and wildlife biologists.

Eighty more birds will be released in the spring of 2016 and another 80 in 2017.

"Wild quail had been extirpated from the Pinelands since at least the late 1980s, so knowing that the translocated quail are adapting to the site and are breeding demonstrates that forest stewardship, coupled with translocation, can help restore quail to the New Jersey Pinelands," Parke said.

The discovery of the nests means "the quail are finding the resources they need to mate and that the conditions at the site are good for their biology," said John Cecil, New Jersey Audubon's vice president for stewardship. "They're finding good cover, building nests and mating."

The quail stayed together when they first arrived as a kind of defense mechanism, then broke off from the covey when they felt more comfortable. "We expect to find additional nests," Cecil said. Each female "can produce seven to 28 eggs.

"We're hoping the young birds will remain and breed in the future," he said. "The indicators are positive."

Project researcher and graduate student Will Macaluso of the University of Delaware found nests tucked away in tall grass while radio-tracking the released birds at the study site.

The quail usually incubate their eggs for 23 days, leaving the nest for only brief times to feed. After the eggs hatch, the female broods the young briefly and then leads them away from the nest to places where they can feed on insects.

"Finding these first nests is exciting, as this confirms that those individuals released are indeed reproducing, giving us great hope going forward," said project collaborator Theron Terhune of Tall Timbers Research Station and Land Conservancy.

The site was created as a haven for the quail. The goal is "to restore and enhance early successional habitat to provide sufficient habitat to sustain a quail covey for their entire life cycle throughout the year," said Dave Chanda, director of the New Jersey Division of Fish and Wildlife.

For the Haines family, which owns the land, the return of quail is welcome. "If the quail are nesting, this means we're taking care of the land exactly the way we're supposed to," said Stefanie Haines, a social media coordinator for Pine Island Cranberry Co.

"This is about the ecology of the land," added forester Bob Williams.

Because of forest management practices, quail feel at home in New Jersey again. "So far, so good," said Parke.