At the drop of a hat — and even without that signal — he rolls on his back, tucks in his wings, curls up his legs and claws and to all intents and purposes is dead. Only his bright red eyes and an occasional craning of the neck show that Percy is playing possum.

No matter where he is or where you put him, Percy keeps up the pose. On the top of the television, on the rim of the cup he won at the Royal Welsh Show, or tossed in the air, he holds it.

Even putting him on the floor next to Suzie the cat doesn’t cause a twitch.

Basically, the Songbird Saver consists of a small dummy bird which, when nudged by a cat for any reason, explodes.
Slattery's own news release describes its effectiveness perhaps more vividly:
"Slipping out of the house, the trainee-cat will make its stealthily stalking approach... Seeing it (the Songbird Saver), apparently frozen with terror, the trainee-cat will pounce upon it, and with the resulting explosion, that cat will go about 9 feet in the air and take off for the high timber before its feet touch the ground."
It is with this simple device that Slattery hopes to save civilization "as we know it."
"Songbirds are vital to our ecology of life," he explained. "Our society could not exist without them. Frankly, in six years we'd be up to our neck in insects."
Slattery emphasized his device is harmless to cats and uses merely the same sort of exploding caps used in cap pistols. It is based on common theories of preconditioning and some stuff he read by Mark Twain on a cat's ability to learn.
"It's based, actually, on a combination of Pavlov and Mark Twain. If both those guys are wrong, I'm wrong."
The dapper 54-year-old promoter denied he was "anti-cat" and said that in fact his invention would allow cats and birds to live together in harmony.