SAN DIEGO (AP) _ A California condor chick, inspired by recordings of vulture hisses and grunts, was slowly chipping its way out of its shell today, San Diego Wild Animal Park officials said.

''Everything is proceeding fine,'' park spokeswoman Martha Baker said this morning. ''The chick is moving around inside the shell and the condor keepers can hear the chick tapping.''

''What we're trying to do is provide a natural stimulus to the bird to assist it in hatching,'' spokesman Tom Hanscom said Wednesday.

The chick, the first ever of the nearly extinct species to be conceived in captivity, began its three-day struggle to break free of its blue-green egg early Wednesday.

A successful hatching would raise the population to 28. All 27 California condors are in captivity, 14 at the Wild Animal Park and 13 at the Los Angeles Zoo.

Baker said park officials still expect the chick to hatch Friday or Saturday. If the chick hasn't emerged from its shell by 4 a.m. Saturday, keepers likely will help it out, Hanscom said.

Meanwhile, keepers are playing recordings of bird noises and gently tapping the egg with a light metal rod every two hours to simulate what condor parents would do to encourage the youth, he said.

The chick has settled into a rhythm of pecking and resting, punctuated by cheeps, and appears to be strong and healthy, said Bill Toone, curator of birds at the park.

''At this point, it will continue to push at the pip hole and situate itself so that it will attempt to cap the egg,'' Hanscom said, referring to the chick's chipping all the way around the egg so it can push the upper third of the shell away from the rest.

The egg is being watched on a remote television monitor but keepers are reluctant to help the chick because of the danger that blood vessels linked to a surrounding membrane will rupture, which could cause fatal bleeding.

Since 1983, there have been 14 successful condor hatchings at the Wild Animal Park and the affiliated San Diego Zoo involving eggs taken from the wild. All of those hatchings occurred with human help, although one of those chicks died of an infection 24 hours after birth.

The egg was laid March 3 at the park's ''condorminium'' after its parents engaged in the first captive mating in the history of a 15-year program aimed at saving North America's largest land bird. California condors, which are scavengers, have wing spans of up to 10 feet.

State and federal wildlife officials overseeing the condor program decided to remove the remaining condors in the wild to focus efforts on a captive breeding flock. The last known California condor in the wild was captured in April 1987.