Four Pacific fisher kits who were returned to the wild last week will be closely monitored by UC Berkeley wildlife biologists who are interested in knowing how the animals assimilate to the forest after being reared in captivity, according to the Fresno Bee.

The kits were rescued last May, when their mothers - part of a multi-year Pacific fisher study - were killed, one by a bobcat, the other by a car. UC Berkeley wildlife biologist Rick Sweitzer delivered the animals to the Fresno Chaffee Zoo, where they were nursed to health.

Zoo veterinarian Lewis Wright told Bee reporter Marc Benjamin that zoos are preferable to ordinary veterinary hospitals for weasel-like fishers because the wild animals are susceptible to dog and cat illnesses. The juvenile fishers were later pen reared near Bass Lake.

The fisher rescue and release became part of the seven-year Sierra Nevada Adaptive Management Project, in which fishers are fitted with radio transmitter collars and monitored to study their fate in a forest ecosystem subject to timber harvest and development.

Currently 23 fishers are monitored daily. Scientists surgically implanted transmitters in the four fishers released last week to eliminate the risk of losing their collars.