(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
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.
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