Shifting Winds Disrupt Island Birds' Feeding Habits

  • Playlist
  • Download
  • Embed
    Embed <iframe src="http://www.npr.org/player/embed/11253445/11260702" width="100%" height="290" frameborder="0" scrolling="no">
  • Transcript
A Cassin's Auklet chick from the Farallon Islands. i

Although most Cassin's Auklets have stayed put in their nests this year, many chicks are weak and have died of starvation. Alaska Science Center/U.S. Geological Survey hide caption

itoggle caption Alaska Science Center/U.S. Geological Survey
A Cassin's Auklet chick from the Farallon Islands.

Although most Cassin's Auklets have stayed put in their nests this year, many chicks are weak and have died of starvation.

Alaska Science Center/U.S. Geological Survey
An aerial view of the Farallon Islands. i

Thousands of migratory birds fly to feed and breed on the Farallons Islands, located off the northern coast of California. National Oceanic and Atmospheric Administration hide caption

itoggle caption National Oceanic and Atmospheric Administration
An aerial view of the Farallon Islands.

Thousands of migratory birds fly to feed and breed on the Farallons Islands, located off the northern coast of California.

National Oceanic and Atmospheric Administration
A dinghy is lifted by a crane onto the Farallon Islands. i

The only way of reaching the islands is by crane and dinghy, as winter storms have torn away all of the docks. John Nielsen, NPR hide caption

itoggle caption John Nielsen, NPR
A dinghy is lifted by a crane onto the Farallon Islands.

The only way of reaching the islands is by crane and dinghy, as winter storms have torn away all of the docks.

John Nielsen, NPR
One of many birds that migrate to the Farallon Islands. i

More than a dozen sea-bird species make their nests every year on the Farallon Islands, creating a population of 200,000 birds. National Oceanic and Atmospheric Administration hide caption

itoggle caption National Oceanic and Atmospheric Administration
One of many birds that migrate to the Farallon Islands.

More than a dozen sea-bird species make their nests every year on the Farallon Islands, creating a population of 200,000 birds.

National Oceanic and Atmospheric Administration
An adult Cassin's Auklet bird. i

The Cassin's Auklet has been one of the most frequently spotted birds on the Farallon Islands. But dwindling food supplies could change that. National Oceanic and Atmospheric Administration hide caption

itoggle caption National Oceanic and Atmospheric Administration
An adult Cassin's Auklet bird.

The Cassin's Auklet has been one of the most frequently spotted birds on the Farallon Islands. But dwindling food supplies could change that.

National Oceanic and Atmospheric Administration

Thirty miles west of the San Francisco Bay are the Farallon Islands, shards of granite once known as "the Devil's Teeth."

Every spring, hundreds of thousands of migratory sea birds fly there to breed and feast on sea life in the waters nearby.

Recently, some of those birds began to abandon their nests. The birds may be acting as an early indicator of profound shifts now under way in global currents of wind and water — a consequence of climate change.

Scientists have monitored the birds on the Farallon Islands for 40 years. It's a wildlife refuge, closed to tourists and settlers. There are no docks there; scientists take sailboats close to the island, then board a yellow dinghy that takes them close to the cliffs. A crane then hoists them onto dry land.

As the boat rises, an amazing sight comes into view: hundreds of thousands of birds' nests.

"Pretty much every square inch of the island is used by one species or another," says biologist Pete Warzybok. "Between the 12 species breeding here they cover every bit."

Warzybok works with PRBO Conservation Science, a non-profit group that studies the sea birds for the U.S. Fish and Wildlife Service.

"Welcome to the Farallons National Wildife Refuge," he says. Shrieking western gulls launch do dive-bomb attacks on the visitors nearby.

The harsh surroundings on the islands — bare rocks, howling winds, and wicked winter storms — are "perfect for sea birds," he says: "They make the most of it, and they usually thrive out here."

The seabirds thrive because those howling winds have turned this refuge into one big feeding trough. Almost every spring, they churn the ocean in a way that pulls bottom waters to the surface.

Scientist Russ Bradley says these giant upwellings are usually full of tiny animals called krill. And that's what sea birds eat.

"It's really the base of the ocean food chain in this area," Bradley says. "As the krill goes, so goes the system."

Bradley says that point was pounded home three years ago, when something knocked this ecosystem out of whack, as sea bird populations crashed. The Cassin's Auklet, a nocturnal species with a distinctive call that was once among the islands' most common birds, seemed to fall right through the floor.

The sudden demise of the auklet turned it into a poster species for the effects that global climate change can have on wildlife. Three yeas ago, after flying in and breeding as usual, many of the auklets abruptly flew away, abandoning their nests.

"They laid eggs, but they just could not continue the effort," says Warzybok. "It takes a lot of energy to breed, and there just wasn't enough food out there to support that effort, so they abandoned the eggs."

Warzybok and Russ Bradley read through 40 years of field notes kept by sea-bird experts on the islands. They found nothing close to what they had seen. But one year later, Bradley says, they saw it happen again.

Bradley isn't sure what forced this change. He believes that in recent years, the jet stream has changed its path in ways that may be linked to the gradual warming of the globe. This change in the jet stream may, in turn, have disrupted the winds that normally sustain birds on the Farallons.

This year, the birds are doing slightly better. Cassin's Auklets stayed on their nests, but the chicks have not done well. Many are small are weak and some have died of starvation. Apparently, krill once again are scarce in the water around the islands.

If these changes spread they could disrupt up one of the most productive ocean currents in the world. It runs from Alaska down to Baja California and it is full of commercially important fish that feast on krill. If these fish stocks were to crash, the economic impact could be huge and lasting.

Comments

 

Please keep your community civil. All comments must follow the NPR.org Community rules and terms of use, and will be moderated prior to posting. NPR reserves the right to use the comments we receive, in whole or in part, and to use the commenter's name and location, in any medium. See also the Terms of Use, Privacy Policy and Community FAQ.