Massadona, Colo. ? A team of state and federal wildlife biologists converged in northwest Colorado early last week to release 18 black-footed ferrets into the wilderness, coaxing the shy mammals out of cages into dark prairie dog holes.

The release, the fifth this year in the region, was part of ongoing efforts to reintroduce the black-footed ferret to its historic rangeland nearly 20 years after the masked mammal was rescued from the brink of extinction.

Biologists from the Colorado Division of Wildlife released three adult female ferrets and 15 kits in the Wolf Creek Management Area, about 35 miles southeast of Dinosaur National Monument.

The release site is in the remote White River region of northwest Colorado, where extensive prairie dog towns dot a dry, scrubby landscape.

The release brings to 58 the number of black-footed ferrets that biologists have released in the area.

Biologists plan to return to the WCMA in early November to assess the well-being of recently released black-footed ferrets, to learn how the mammals are faring in their new digs.

The region is one of the few remaining areas in Colorado where biologists believe ferrets can make a comeback.

Wildlife biologists are hopeful that black-footed ferrets, nocturnal hunters, soon will reproduce and thrive in the area. The region is ideal ferret land. Prairie dogs make up about 90 percent of the mammal’s diet.

In addition, black-footed ferrets inhabit prairie dog burrows with their young.

All of the black-footed ferrets released in Colorado in recent years are descendants of the original seven ferrets discovered in Wyoming in the mid-80s.

Before the discovery, scientists believed the animal had become extinct.