Rosie, Freida and Fern could make their first venture into the hardwood hammocks of their new home on North Key Largo today.<br><br>Although they are Key Largo woodrats, the trio of endangered species arrived in the Keys only last week.</p><p>On Feb. 2, they were placed in manmade nests in the Crocodile Lake National Wildlife Refuge as part of the first-ever attempt to introduce captive-bred woodrats into their natural habitat.</p><p>After a week to acclimate Rosie, Freida and Fern -- born and raised at Tampa's Lowry Park Zoo -- to their surroundings, a wire cage around each nest will be removed today.</p><p>On Tuesday, cages were removed from nests holding four woodrats bred at Disney's Animal Kingdom near Orlando.</p><p>Another seven woodrats, all from Animal Kingdom's breeding facility, are expected to arrive this week for release around Feb. 22.</p><p>"This is an exciting thing," said refuge manager Steve Klett. "It involves a whole lot of people, from our local refugee volunteers to our agency staff, and the folks at Lowry Park and Disney."</p><p>All the released woodrats, adults of breeding age, are fitted with radio-tracking collars. "We hope to learn a little more about the habitat that the woodrat requires and what we can do to preserve it," Klett said.</p><p>Key Largo woodrats, found only on in the tropical hardwood hammocks of their namesake island, were declared an endangered species in 1984. At one point, the population likely dropped to fewer than 90 rats.</p><p> The acquisition of North Key Largo hammocks for conservation has helped the population increase, but biologists remain concerned that limited habitat now also home to nonnative predators like big snakes and feral cats could wipe out the woodrat.</p><p>Everyone associated with woodrats always emphasizes one point: They are nothing like the common black rat, itself an invasive species.</p><p>"The rodents make their homes in forested areas to avoid human interaction," said Andrea Finger of Disney.</p><p>Since 2006, Disney has bred 18 litters of woodrats, resulting in 30 pups.</p><p>"It was a bit of a challenge because so little was known about how the woodrat mates and reproduces," Finger said. "They're nocturnal and elusive, and there are not that many of them."</p><p>It turns out woodrats are generally solitary, the females only tolerating males during twice-a-year breeding periods. Litters typically are one to three pups.</p><p>Starting with four woodrats from Key Largo, Lowry Park launched its woodrat efforts in 2002, and was the first facility to successfully breed the species in captivity. With another 11 woodrats transplanted from the Keys, Lowry Park has produced litters resulting in 20 pups.</p><p>"Conservation starts at home," said Lowry Park Zoo veterinarian David Murphy. "It's an exciting time to see this program come full circle with the release of captive-born woodrats into their native habitat."