Some interesting research for pelagic birders. Do the first birds on
the scene of a burley slick normally approach from downwind? I wonder
if more birds might be attracted if some of the burley is held aloft
so the scent carries further.
Wandering Albatrosses Follow Their Nose
March 6, 2008
The first study of how individual wandering albatrosses find food
shows that the birds rely heavily on their sense of smell. The birds
can pick up a scent from several miles away, U.S. and French
researchers have found.
"This is the first time anyone has looked at the odor-tracking
behavior of individual birds in the wild using remote techniques,"
said Gabrielle Nevitt, professor of neurobiology, physiology and
behavior at UC Davis and an author on the study with UC Davis graduate
student Marcel Losekoot of the Bodega Marine Laboratory and Henri
Weimerskirch of the Centre National de la Recherche Scientifique,
Wandering albatrosses fly for thousands of miles across the ocean,
usually gliding a few feet above sea level. Floating carrion,
especially squid, make up a large part of their diet.
Albatrosses nesting on Possession Island in the southwestern Indian
Ocean were fitted with GPS receivers that recorded their exact
position every 10 seconds and stomach temperature gauges that noted
every meal. When the birds returned to land after a foraging trip, the
researchers removed the equipment and downloaded the data.
They found that the birds usually flew across the wind, which allows
them to cross plumes of scent drifting downwind and is also the best
strategy for energy-efficient soaring.
Sometimes birds would fly straight to food, but almost half the time
an albatross would either turn upwind or zigzag into the wind toward a
meal. Both patterns suggest that the birds were following a plume of
scent, rather than visual cues. Birds could turn upwind toward a food
source several miles away -- well over the visual horizon.
Hunting by scent allows the albatross to cover a strip of ocean
several miles wide as it flies crosswind, Nevitt said.
Wandering albatrosses and their relatives do not appear to have
particularly good eyesight, compared with other predatory birds, and
their eyes may be adapted to scan movement on the horizon. That might
help them detect other groups of other birds gathered around food.
The study is published online by the journal Proceedings of the
National Academy of Sciences and was funded by grants from the French
Polar Institute and the U.S. National Science Foundation.
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