He hurried to the airport and to his plant.

The watchbird was operating erratically now. Many of its delicate parts were out of line, worn by almost continuous operation. But gallantly it responded when the stimuli came.

A spider was attacking a fly. The watchbird swooped down to the rescue.

Simultaneously, it became aware of something overhead. The watchbird wheeled to meet it.

There was a sharp crackle and a power bolt whizzed by the watchbird's wing. Angrily, it spat a shock wave.

[Ill.u.s.tration]

The attacker was heavily insulated. Again it spat at the watchbird. This time, a bolt smashed through a wing, the watchbird darted away, but the attacker went after it in a burst of speed, throwing out more crackling power.

The watchbird fell, but managed to send out its message. Urgent! A new menace to living organisms and this was the deadliest yet!

Other watchbirds around the country integrated the message. Their thinking centers searched for an answer.

"Well, Chief, they bagged fifty today," Macintyre said, coming into Gelsen's office.

"Fine," Gelsen said, not looking at the engineer.

"Not so fine." Macintyre sat down. "Lord, I'm tired! It was seventy-two yesterday."

"I know." On Gelsen's desk were several dozen lawsuits, which he was sending to the government with a prayer.

"They'll pick up again, though," Macintyre said confidently. "The Hawks are especially built to hunt down watchbirds. They're stronger, faster, and they've got better armor. We really rolled them out in a hurry, huh?"

"We sure did."

"The watchbirds are pretty good, too," Macintyre had to admit. "They're learning to take cover. They're trying a lot of stunts. You know, each one that goes down tells the others something."

Gelsen didn't answer.

"But anything the watchbirds can do, the Hawks can do better," Macintyre said cheerfully. "The Hawks have special learning circuits for hunting.

They're more flexible than the watchbirds. They learn faster."

Gelsen gloomily stood up, stretched, and walked to the window. The sky was blank. Looking out, he realized that his uncertainties were over.

Right or wrong, he had made up his mind.

"Tell me," he said, still watching the sky, "what will the Hawks hunt after they get all the watchbirds?"

"Huh?" Macintyre said. "Why--"

"Just to be on the safe side, you'd better design something to hunt down the Hawks. Just in case, I mean."

"You think--"

[Ill.u.s.tration]

"All I know is that the Hawks are self-controlled. So were the watchbirds. Remote control would have been too slow, the argument went on. The idea was to get the watchbirds and get them fast. That meant no restricting circuits."

"We can dope something out," Macintyre said uncertainly.

"You've got an aggressive machine up in the air now. A murder machine.

Before that it was an anti-murder machine. Your next gadget will have to be even more self-sufficient, won't it?"

Macintyre didn't answer.

"I don't hold you responsible," Gelsen said. "It's me. It's everyone."

In the air outside was a swift-moving dot.

"That's what comes," said Gelsen, "of giving a machine the job that was our own responsibility."

Overhead, a Hawk was zeroing in on a watchbird.

The armored murder machine had learned a lot in a few days. Its sole function was to kill. At present it was impelled toward a certain type of living organism, metallic like itself.

But the Hawk had just discovered that there were other types of living organisms, too--

Which had to be murdered.

--ROBERT SHECKLEY

Transcriber's Note:

This etext was produced from _Galaxy Science Fiction_ February 1953.

Extensive research did not uncover any evidence that the U.S.

copyright on this publication was renewed. Minor spelling and typographical errors have been corrected without note.