seems the birds don't stop all murders."

"Why not?"

"Some murderers don't have these brain waves," the captain answered,
trying to remember what the newspaper article had said. "Or their glands
don't work or something."

"Which ones don't they stop?" Celtrics asked, with professional
curiosity.

"I don't know. But I hear they got the damned things fixed so they're
going to stop all of them soon."

"How they working that?"

"They learn. The watchbirds, I mean. Just like people."

"You kidding me?"

"Nope."

"Well," Celtrics said, "I think I'll just keep old Betsy oiled, just in
case. You can't trust these scientists."

"Right."

"Birds!" Celtrics scoffed.

* * * * *

Over the town, the watchbird soared in a long, lazy curve. Its aluminum
hide glistened in the morning sun, and dots of light danced on its stiff
wings. Silently it flew.

Silently, but with all senses functioning. Built-in kinesthetics told
the watchbird where it was, and held it in a long search curve. Its eyes
and ears operated as one unit, searching, seeking.

And then something happened! The watchbird's electronically fast
reflexes picked up the edge of a sensation. A correlation center tested
it, matching it with electrical and chemical data in its memory files. A
relay tripped.

Down the watchbird spiraled, coming in on the increasingly strong
sensation. It _smelled_ the outpouring of certain glands, _tasted_ a
deviant brain wave.

Fully alerted and armed, it spun and banked in the bright morning
sunlight.

Dinelli was so intent he didn't see the watchbird coming. He had his gun
poised, and his eyes pleaded with the big grocer.

"Don't come no closer."

"You lousy little punk," the grocer said, and took another step forward.
"Rob me? I'll break every bone in your puny body."

The grocer, too stupid or too courageous to understand the threat of the
gun, advanced on the little thief.

"All right," Dinelli said, in a thorough state of panic. "All right,
sucker, take--"

A bolt of electricity knocked him on his back. The gun went off,
smashing a breakfast food display.

"What in hell?" the grocer asked, staring at the stunned thief. And then
he saw a flash of silver wings. "Well, I'm really damned. Those
watchbirds work!"

He stared until, the wings disappeared in the sky. Then he telephoned
the police.

The watchbird returned to his search curve. His thinking center
correlated the new