This year's only surviving California condor egg was destroyed today, despite a last-minute declaration of war by the U.S. government against a pair of ravens blamed for the tragedy.

Inez Connor, speaking for the U.S. Fish and Wildlife Service, said a condor parent sitting on the grapefruit-sized egg lurched toward a marauding raven at daybreak, inadvertently knocking the egg off a cliff edge. The raven and its mate swooped down and ate the remains.

It was another frustrating blow to scientists trying to preserve the rare condor, for they had decided yesterday, after consultation with agencies in Washington and Sacramento, to dispatch a team today to shoot the ravens.

The egg had been greeted with surprise and pleasure by the scientists when it appeared three weeks ago, after the same parents had knocked their first egg of the season off their perch during a dispute over incubation rights.

The second egg proved for the first time that the huge, rare bird--its wingspan ranges up to 12 feet, and there are said to be only 30 left on earth--could produce more than one egg in a season, a finding of great significance for the government's plan to breed the bird in captivity.

Apparently liking the taste of the remains of the first egg, the ravens followed the condor parents to a new cliffside perch in the mountains northeast of Ventura, where the second egg was laid.

On Thursday, according to scientists watching through a telescope from a quarter mile away, the condor parents began to squabble again over which one should sit on the egg. While they chased each other, one of the ravens pecked at the unprotected egg for several minutes.

Scientists, concluding that the egg had not been punctured but was in danger, decided to shoot the ravens. This morning they watched helplessly as the egg was destroyed before they could mount an expedition.

Connor said the scientists do not know if the condor pair can produce a third egg so late in the breeding season. The scientists are unable to explain the recurrent bickering between the condor parents, Connor said, but are beginning to wonder if "the harassment by the ravens has affected the condor pair."

The scientists have noticed a ledge where they suspect another condor pair may have laid an egg, but can't get a clear view.