October 30, 2013 at 2:06 am #844MikeKeymaster
Didn’t a similar event happen recently in the UK?
this looks to be a huge story, tho i haven’t seen
anything reported on the regular news….
VANCOUVER — As he scrambled over the rocky outcrops of remote
Triangle Island this spring, seabird population biologist Mark
Hipfner knew immediately something had gone wrong.
Tens of thousands of nests that should have been brimming with eggs
were empty. And in the weeks that followed, as hundreds of thousands
of seabirds flocked to the windswept islet, 45 kilometres north of
Vancouver Island, the problem only got worse.
Data are still being collected, but with the nesting season almost
over, Mr. Hipfner says, it is now clear that Triangle Island’s
internationally significant seabird population is experiencing the
worst breeding year on record.
“We are seeing a very severe nesting failure — the worst ever,” said
Mr. Hipfner, who works for the Canadian Wildlife Service. According
to Mr. Hipfner, the Cassin’s auklet population of 500,000 pairs is
unlikely to produce even one chick that survives.
Several other bird species, all hampered by a lack of food, are also
struggling to reproduce, although they are not as hard hit as
“Most Cassin’s auklets did not lay eggs. The birds that laid eggs
failed to hatch them and those that did hatch, have failed to raise
the chicks,” said Mr. Hipfner, who ties the problem to a coast-wide
collapse of oceanic plankton.
The plankton blooms, which are caused by upwelling of cold ocean
currents, didn’t occur this year for reasons that aren’t clear, but
which may be linked to global warming. Without the plankton, the
small fish species that support the seabirds have died off, creating
a scenario where the adult birds lack the energy to produce eggs and
the chicks that do hatch soon starve to death.
The nesting failure could be an early warning sign of problems facing
other species — from sockeye salmon to baleen whales — that depend
on zooplankton such as krill, a tiny shrimp-like crustacean that has
vanished along much of the West Coast.
“If you’ve got a failure at the base, it cascades throughout the food
web,” Mr. Hipfner said. “It’s a single big system that’s all
interconnected. . . . Without plankton, essentially the whole system
comes to a standstill.”
He said oceanic plankton has disappeared along the full length of the
California Current, which circulates on the West Coast of North
America from California to British Columbia’s mid coast.
Triangle Island, which supports one of the most significant seabird
nesting colonies in North America, marks the northern edge of the
Mr. Hipfner said seabird populations farther north, on the Queen
Charlotte Islands, are in a different ocean regime and this year are
enjoying a highly successful breeding season.
But the failure at Triangle Island is of international significance.
The rocky outcrop, so blasted by winds that trees don’t grow on it,
has an estimated population of one million Cassin’s auklets — half
the world’s supply — 60,000 tufted puffins, 80,000 rhinoceros
auklets and 8,000 common murres.
“It’s a remarkable place,” Mr. Hipfner said. “Personally, it is very
difficult to be in a colony where you know there is such a
significant nesting failure. But as a scientist, you know the birds
are making the right choice. The key for the species is to survive to
breed a number of times, so the loss of one season is not that
Mr. Hipfner said there have been poor breeding seasons in past years
and the colony should bounce back if conditions are good next year.
“The concern is that these [oceanic] events could become more
frequent because of global warming. That is the real worry.”
Not only are the birds having difficulty reproducing, but many adults
are also growing weak, and it is expected the number that survive to
breed again will decline sharply. In a typical year, 85 per cent of
the adults survive. This year the survival rate is expected to drop
to 60 per cent.
Seabird biologists from B.C. to California are noting breeding
problems this year.
Bill Sydeman, director of marine ecology at the Point Reyes Bird
Observatory in California, has said the Farallon Islands, off San
Francisco, are experiencing the worst breeding season ever recorded.
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