scared to death

(from: Vancouver Sun, Dec. 9, 2011, By Margaret Munro, Postmedia News)

" ...Clinchy says cats should not be allowed in wildlife areas as previous studies have shown that feral and domestic cats directly kill 22 per cent of birds in Victoria parks. He says the fear effect is likely reducing the number by another 20 per cent... "

Life on idyllic-looking islands in British Columbia took a noisy and decidedly deadly turn when biologist Liana Zanette set out to measure the effect of fear.
She and her colleagues hung speakers near song sparrow nests and began broadcasting the sounds of hawks, raccoons and other predators.
The sparrows were so scared they experienced something akin to post-traumatic stress. They laid fewer eggs and were so flustered many of their chicks starved to death.
By the end of the four-month experiment the sparrows had produced 40-per-cent fewer young than normal, demonstrating what scientists say is the very real effect of fear.
The results, published today in the journal Science, indicate the mere sound and presence of predators can be just as deadly as their claws and fangs.
"This effect can be as important as direct killing," says Zanette, of the University of Western Ontario.
She and her colleague, Michael Clinchy, a biologist at the University of Victoria, say the fear effect is common in animals and needs to be considered when managing wildlife: be it elk looking over their shoulders for wolves in national parks or birds flitting away from urban rats and cats.
"Wild animals are in peril every moment of every day of being torn limb from limb by any number of predators," says Clinchy, who says the stress response to predators may have parallels with post-traumatic stress disorder in humans.

Read more: The Vancouver Sun