http://news.independent.co.uk/uk/environment/story.jsp?story=507878
Terns feel the chill as seabird numbers rise to new heights
By Michael McCarthy, Environment Editor
03 April 2004
Seabirds now one of Britain's greatest wildlife assets, with booming
populations that are among the largest and most important in the world,
an intensive survey has shown.
Numbers around the coasts of Britain and Ireland have risen steadily
for the past 30 years, from five million to eight million, making the
British Isles one of the key seabird areas on earth. In Scotland,
breeding seabirds (5.2 million) now outnumber people (5.1 million).
Remarkably, the British Isles alone contain 60 per cent of the world
population of the great skua, nearly 70 per cent of the world's gannets
and 90 per cent of the world's Manx shearwaters. But although most
seabird species are prospering, a small number, terns in particular,
are undergoing worrying declines.
The astonishingly detailed picture of the status of 25 different
breeding species is contained in the report of Seabird 2000 , a census
of all the seabird populations of the UK, the Republic of Ireland, the
Isle of Man and the Channel Islands. It was carried out between 1998
and 2002 by more than 1,000 observers who surveyed 3,200 colonies along
25,000 miles of coastline, and who also surveyed 900 colonies inland.
The results, which are due to be presented this weekend at the eighth
International Seabird Conference in Aberdeen, provide a welcome relief
from the gloomy bulletins of recent years; first it was announced
Britain's farmland birds such as skylarks and grey partridges were in
sharp decline; then it was our woodland birds, such as willow tits,
that were dwindling.
In contrast, more than half of all seabird species have increased in
number by more than 10 per cent in the past 30 years, and some of
Britain's best-known seabirds are booming as never before, with three
now over the million mark.
Top of the list is the guillemot, the cliff-nesting, penguin-
lookalike, whose numbers have risen exponentially over the past 30
years. In 1969, when the first such survey was carried out, there were
650,000, rising in the mid-1980s to 1.2 million, to 1.9 million today.
Its success story is almost equalled by most people's favourite
seabird, the puffin, the one with the rainbow beak, which over the same
period has gone from 900,000 birds to 1.2 million. Puffins are doing
particularly well on the eastern side of Britain, in such places as the
Farne and Coquet islands off Northumberland.
The third million-plus species is the fulmar, the large, stiff-winged
petrel whose spread around Britain was one of the most remarkable bird
sagas of the past century. In 1878 they nested only on remote St Kilda,
west of the Hebrides, but in the next hundred years they established
themselves all around the British coastline. They increased from
600,000 birds in 1969 to nearly 1.1 million in 1985 and are now
maintaining that number, indicating that they may have a reached a
natural limit to their expansion.
Another species showing a great boom in numbers is the great skua or
bonxie, a heavily-built gull-like predator which lives by robbing other
seabirds of their fish prey, or even killing and eating them directly.
It now numbers about 20,000, mainly in the northern and western isles
of Scotland.
One of the principal reasons for the increases is simply that the
British Isles present such a remarkable, fertile breeding ground for
seabirds, said the Seabird 2000 project co-ordinator Ian Mitchell. "As
a group of islands with a rich and varied coastline, we have a plethora
of nesting habitats," said Dr Mitchell, from the Joint Nature
Conservation Committee in Aberdeen, which organised the census with the
Royal Society for the Protection of Birds and a number of other groups
and agencies.
He added: "We have lots and lots of islands which are free of mammalian
predators, which is where you get the largest aggregations of
ground-nesting seabirds. The water around us is supplied with nutrients
from the ocean currents in the Atlantic, so food is plentiful.
"You only have to go to the Mediterranean, where you have mile after
mile of rocky coastlines with no seabirds on them at all, to see waters
that aren't so productive. The habitats are here, the food is here and,
also, we don't persecute seabirds here."
There is no doubt that seabirds are now one of Britain's principal
wildlife assets, he said. Dr Norman Radcliffe, who led the RSPB team on
the survey, agreed. "A visit to a seabird colony in the summer fills
the senses, and these colonies provide some of the most exciting
wildlife spectacles these islands can offer," he said. "The presence of
eight million seabirds provides living proof of the richness of the
seas around our islands. But these birds are also sensitive living
barometers and the declines of some species are highly worrying." Those
declines seem to be mainly affecting species which feed near the
surface on sandeels, the commonest seabird meal - the small silvery
fish often seen carried in the beak of a puffin.
Three types of tern, arctic, little and sandwich, have gone down
significantly in numbers between 1985 and the current survey, dropping
by 29 per cent, 25 per cent and 11 per cent respectively. Kittiwakes (a
gull species) and shags (small cormorants) have also dropped, by 23 per
cent and 25 per cent. Sandeel shortages are thought to be behind these
declines, although the survey scientists stress it is too simplistic
simply to blame the fishing industry, as has been done in the past. It
may be to do with more complicated ecological factors, such as the
depth at which the sandeels are found.
Species which are thriving, including guillemots and puffins, can dive
to tremendous depths - a guillemot has been photographed by a
remotely-operated submersible more than 500ft below the surface of the
North Sea.
Different skills, however, are needed inland. The Seabird 2000 survey
found 20,000 pairs of herring gulls nesting on rooftops in British
towns and cities, double the number the last urban gull survey in 1994.
The losers...
Little tern (Sterna albifrons): Numbers have dropped by a quarter,
perhaps because more chicks are being taken by foxes and kestrels
Kittiwake (Rissa tridactyla): Still the most abundant gull in the
British Isles, with about 800,000 breeding birds, but numbers have
fallen by a quarter
Arctic Skua (Stercorarius parasiticus) May be suffering from the
bullying competition of its more aggressive relative, the bonxie
Arctic tern (Sterna paradisea): Numbers have gone down by nearly a
third in the past two decades, probably because of a shortage of
sandeels
...and winners
Common Guillemot (Uria aalge): Now Britain's most numerous seabird, its
population has reached 1.6 million
Fulmar (Fulmarus glacialis): After a century-long expansion, the
fulmar's population seems to have stabilised at just over one million
Great Skua (Catharacta skua): Also known as the bonxie, this heavily
built predator and robber of other seabirds is flourishing
Puffin (Fratercula arctica): The small burrow-nester has now reached
about 1.2 million around the British Isles
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