http://reporter.leeds.ac.uk/press_releases/current/gannets.htm
Gannet population under threat from global warming
18 June 2007
Researchers at the University of Leeds have warned that global warming
is a major threat to the gannet, a species known for its stable
populations and constant breeding success.
In a paper published in Marine Ecology Progress Series, Dr Keith Hamer
of the University’s Faculty of Biological Sciences reports that
diminishing fish stocks around gannets’ natural habitats – caused
partly by an increase in sea temperature – are forcing birds to search
further afield in search of food for their young.
“Usually, one parent will stay with a chick while the other goes out
hunting, says Dr Hamer. “But if left for long enough, it will
eventually leave the nest itself to find food. This leaves the chick
alone and vulnerable to attack - mainly from other gannets seeking
prime nesting space, which is fiercely contested within colonies.”
Two thirds of the world’s gannets nest in the UK, with the largest
northern gannet colony found in the Scottish islands of St Kilda. Dr
Hamer’s research group has been studying birds nesting at Bass Rock off
the Northumbrian coast, using satellite transmitters attached to the
birds, to gather information about their movements.
“Gannets have been forced to travel as far as the Norwegian coast to
find food – a round trip of over 1000km,” said Dr Hamer. “They
compensate by flying faster to make sure they don’t leave their nests
for too long, but our research shows they’ve hit their limit. They just
physically can’t increase their speed any further.”
Until now, gannets have bucked the trend in the North Sea, their
breeding success remaining stable while other seabirds were in decline.
However, as sea temperatures continue to rise and fish stocks diminish,
gannets are being forced further afield and are away from their nests
for longer. The Leeds researchers are already seeing the numbers of
unprotected chicks rise and fear it can only get worse.
Gannets pair for life and breed annually, occupying the same nest each
year. It takes forty days for an incubated egg to hatch and a further
ninety days for chicks to fledge. “There’s only time for each gannet
pairing to raise one chick each year, so with an increasing number
losing their chicks and their nesting sites we may start to see a
decline in overall numbers,” says Dr Hamer.
For further information contact:
Clare Elsley, campuspr. Tel: 0113 258 9880 Mob: 07767 685168
Email:
Simon Jenkins, University of Leeds Press Office. Tel: 0113 343 5764
Email:
NOTES TO EDITORS:
1. Dr Hamer is a Reader in Animal Ecology at the Institute of
Integrative and Comparative Biology, part of the Faculty of Biological
Sciences at the University of Leeds. The main theme of his research
work is life history-environment interactions in seabirds.
2. This work was published in a paper entitled: Annual variation in
diets, feeding locations and foraging behaviour of gannets in the North
Sea: flexibility, consistency and constraint in Marine Ecology Progress
Series on 24 May 2007.
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