http://www.newscientist.com/news/news.jsp?id=ns99994806
Penguin cameras reveal dive buddies
Miniature cameras mounted on penguins have recorded their social
behaviour underwater for the first time.
Marine birds and mammals spend much of their lives in the open ocean,
making it exceedingly difficult for biologists to study their behaviour.
So Akinori Takahashi, of the National Institute of Polar Research in
Tokyo, Japan, and his colleagues mounted tiny cameras on five Adelie
penguins and five chin-strap penguins to monitor their dives off Signy
Island in Antarctica.
The cameras weighed only 73 grams in air and were held on the penguin's
body by a waterproof tape. They recorded over 11,000 images from 2,140
dives.
Synchronised swimming
The images revealed that the penguins swam underwater with at least one
other bird 15 per cent of the time. Sometimes, as many as 11 penguins
dived together. When the dives were deeper than 20 metres, the penguins
accompanied each other 25 per cent of the time - remaining in close
visual contact at all times.
The cameras did not show the penguins feeding together at the bottom of
their dives, so the researchers think that the birds dive together to
help avoid predators.
The two species of penguins feed on Antarctic krill in a region where
there are also commercial krill fisheries. The researchers want to use
the cameras to determined the extent of any overlap between the
penguins' feeding grounds and the fisheries.
"It'll help us manage the krill fisheries in an eco-friendly way," says
team member Phil Trathan, of the British Antarctic Survey in Cambridge,
UK.
Journal reference: Biology Letters (DOI: 10.1098/rsbl.2004.0152)
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