OCCUPY EAGLE!

Herring gull mobbing a white-tailed eagle. Credit: Markus Varesvuo/naturepl.com.

  
The situation: The breeding season, a mad-as-hell gull defending eggs or chicks, a gigantic maurading scavenger.

CANADIAN SEABIRDS WALLOPED BY BP'S OIL

Northern gannet. Credit: Alan D. Wilson via Wikimedia Commons.

  
A new paper in early view in Biology Letters�a journal of the Royal Society�finds that Canadian migrant seabirds suffered disproportionately the lethal effects of BP's oil catastrophe in the Gulf of Mexico last year.

Northern gannets (Morus bassanus) suffered the highest oiling among beach-wrecked birds recovered last year.

These are the largest seabirds in the Atlantic, who migrate from their Canadian breeding colonies to overwinter in the Gulf of Mexico. Adults return to the breeding colonies by about March�earlier than immature birds.

Winter positions of northern gannets from 4 of 6 North American colonies, where adults and chicks were banded and adults and juveniles tracked. Mean winter (Jan�Feb) positions from adults carrying GLS (2004�2010) and final positions from 18 juveniles with PTTs (2008�2010). Deepwater Horizon site (star) and associated slicks (grey) indicated. Credit: William Montevecchi, et al. Biology Letters. DOI: 10.1098/rsbl.2011.0880.

  
Due to these migration timetables, most of the northern gannets killed in the Gulf last year were likely immature birds.

Which means the real impact of their deaths will not show up until those birds would have reached sexual maturity�at about 5 or 6 years old�or betwen now and far beyond. Gannets can live at least 21 years.

From the paper:

Most adult gannets had returned to Canadian colonies by 20 April 2010, although more than 50,000 immature gannets were in the Gulf at the time and suffered oil-related mortality. Hence, two probable outcomes are (i) a lagged (likely difficult to detect) population decrease or (ii) mortality will be buffered by age-related life-history processes.  

A bonded pair of northern gannets. Credit: Al Wilson via Wikimedia Commons.

  
The authors found the story grew even more ominous when they compared numbers on how many gannets were overwintering in the Gulf of Mexico�numbers that differed hugely depending on the technology used:

• Old-fashioned technology: recovery of banded birds
• Modern technology: bird-borne global location sensors (GLS) and satellite tags (Platform Terminal Transmitters, PTTs)

The newer technologies revealed more than twice as many gannets overwintering in the Gulf. From the paper:

Extrapolation from band recoveries indicates that 13,318 adult gannets winter in the Gulf of Mexico, much less than the 66,124 estimate based on GLS data... PTT positions suggest an estimated population of 52,509 immature gannets in the Gulf compared with 41,587 extrapolated from banding recoveries. Extrapolating tracking data for all gannet age classes more than doubles the estimated number of birds using the Gulf, from 54,905 to 118,633 birds. 

Oiled gannet washed ashore on Cape Cod. Credit: Dennis Minsky at SeaNet.

  
Add to that the fact that dead or oiled birds found ashore represent only a fraction of the birds dead or dying at sea. From the paper:

Seabirds are among the most obvious and immediate indicators of wildlife and environmental damage during marine pollution events. In these circumstances, seabird mortality has been assessed by counting dead and dying animals along coasts. These assessments are biased towards animals that die near accessible well-populated coastlines, and as offshore winds and currents can reduce coastal-deposition of carcasses that sink after a few days, mortality is inevitably underestimated.

The authors note that gannets may be shifting their winter range to the Gulf in response to overfishing of menhaden�their primary winter prey�in Atlantic waters.

Northern gannet in flight. Credit: Andreas Trepte via Wikimedia Commons.

 
And the authors noted possible signs of oil fouling on birds returning to their Canadian breeding colonies:

In April 2011, at their southernmost colony, Cape St. Mary's Newfoundland, gannets on inaccessible cliff-sites were observed and photographed with dark soiled plumage that looked like oil, but this could not be verified by chemical analysis. Tracking, survival and physiological measurements at gannet colonies during 2011 are evaluating other potential repercussions and informing management about conservation concerns.

The paper:

• William Montevecchi, David Fifield, Chantelle Burke, Stefan Garthe, April Hedd, Jean-Fran�ois Rail, Gregory Robertson. Tracking long-distance migration to assess marine pollution impact. Biology Letters. 2011. DOI: 10.1098/rsbl.2011.088.

UPDATE: NEW ZEALAND OIL SPILL THREATENS PENGUINS

A family of little blue penguins, Eudyptula minor, exit their nest burrow. Credit: Noodle snacks via Wikimedia Commons.

  
The New Zealand Herald reports the country is facing one of its worst ecological disasters as the stricken tanker Rena is now in danger of breaking apart. The ship grounded 20 kilometers/12 miles off Tauranga Harbour, near the Bay of Plenty, on the North Island, after striking a reef on Wednesday.

UPDATE: 22:07 GMT, 9 OCT 2011: New Zealand's MetService has issued a severe weather watch for the Bay of Plenty, with strong northeasterly gusts and heavy rains possible in the region today [Monday, New Zealand time]. Officials are advising that oil will start reaching shore at Bay of Plenty's Papamoa beach on Wednesday. Questions remain as to why the large ship hit a well-documented reef in calm waters.

The Rena is carrying 1,700 cubic meters/450,000 gallons of heavy fuel oil. The race is onto siphon off�or at least contain�the oil before the ship sinks. From the New Zealand Herald:

More resources and special equipment [are] likely to be needed during the operation. An offshore boom barrier device to ring-fence the oil�measuring about 1250m [three-quarters of a mile]�was being transported from Australia along with three heavy skimmers to scoop it from the water. A salvage architect was due to arrive from Holland, with further expert help from the Australian Maritime Safety Authority also on their way.

Site of the grounding of the MV Rena, off the North Island of New Zealand. Satellite image courtesy of NASA/JPL/NGA.

  
Meanwhile, heavier weather is bearing down on New Zealand, including a forecast for rain and strengthening northeasterly winds on Monday�when the pumping operation is slated to begin.

Most worrisome, it's spring in the southern hemisphere, and many seabirds along New Zealand's coast are breeding. This is prime egg-laying/chick-hatching season for little blue penguins (called fairy penguins in Australia), who come ashore en masse each dusk to exchange incubation duties or feed their chick, before departing again en masse before dawn to hunt.

(The sound of little blue penguins calling at dusk in New Zealand. Credit: Benchill (Own work) [GFDL or CC-BY-3.0], via Wikimedia Commons.)

So far, seven oiled birds�five little blue penguins and two cormorants�have been taken to a wildlife center at Tauranga Harbour. The New Zealand Herald reports:

"It's a very difficult situation and the reality is that we are going to see a significant oil spill," [Transport Minister Steven] Joyce said. "So far it's been reasonably small, so I think everybody's preparing for the worst. We are dealing with a very serious situation ... and I don't think anybody is under any illusions."

If you haven't met Cookie, the 'ticklish' little blue/fairy penguin at the Cincinnati Zoo, here he is, a sweet ambassador for his kind.

KLEPTOPARASITISM

Kleptoparasitism: 

klepto: Greek ???pt?? ("thief") and ???pt? ("steal") + parasitos: pa??s?t?? ("person who eats at the table of another")

Meaning: The parasitic theft of captured prey, nest material, etc., from animals of the same or another species; such as the theft by a gull* of a featherwight GoPro camera from a tourist on the French Riviera.

*Possibly a European herring gull (Larus argentatus).

(European herring gull. Credit: Kulac via Wikimedia Commons.)

The gull video reminded me of another wild travel video shot by a sea turtle on a "stolen" underwater camera.

The sea turtle video is more likely a case of entanglement than of kleptoparasitism.

AN EXCELLENT YEAR ON RASA ISLAND

(Isla Rasa, Mexico, view from the hut, looking out over the estero. Photo �Julia Whitty.)

I'm finally back from Mexico's remote Isla Rasa, a tiny outpost in the Gulf of California and one of the most important seabird breeding islands in the world.

The island covers a bare 138 acres/56 hectares. Yet it's home to half a million birds�many more if it's a good enough year for the birds to produce eggs, incubate them, and hatch their chicks.

(Heermann's gulls and a card�n cactus, both endemic to the Gulf of California and the Baja Peninsula. Photo �Julia Whitty.)

Some 95 percent of all Heermann's gulls (Larus heermanni) nest on Isla Rasa. These are small, pretty, polite gulls�compared to some of their larger Larid relatives.

Heermann's gull: 

• length 19 inches/48 centimeters
• wingspan 51 inches/129 centimeters

Great black-backed gull: 

• length 30 inches/76 centimeters
• wingspan: 65 inches/165 centimeters

(Grand Central Station Valley, Isla Rasa, Mexico. Photo �Julia Whitty.) 

In the photo above, you can see the nesting territories of the gulls dotting the island's valleys. 

Gulls also nest throughout the rocky hillsides and ridgelines.

(Heermann's gull. Photo �Julia Whitty.)

In fact Heermann's gulls nest on every square inch of this sunbaked, windswept island�except where thickets of cholla cactus have taken hold... and where colonies of terns have usurped them.

(Elegant tern colony in the midst of Heermann's gulls, Isa Rasa, Mexico. Photo � Julia Whitty.)

In the photo above you can see how in one valley elegant terns (Thalasseus elegans) have successfully muscled into the territories of gulls. 

(Elegant terns, Isla Rasa, Mexico. Photo �Julia Whitty.)

The terns nest closer together than the gulls. 

This, and the fact that they move into gull territories en masse and often under cover of night, means they generally get what ground they want�even though they're smaller birds:

Heermann's gull: 

• length 19 inches/48 centimeters
• wingspan 51 inches/129 centimeters

Elegant tern:

• length 17 inches/43 centimeters
• wingspan 34 inches/86 centimeters

(Heermann's gulls and elegant terns, Isla Rasa, Mexico. Photo �Julia Whitty.)

Here's what the two species look like nesting side-by-side.

You can probably already tell from the numbers of birds in the photos that's it's been a very good year so far on the island.

(Heermann's gull chick and eggs. Photo �Julia Whitty.)

By the time I left, chicks were hatching everywhere and the whole island was transformed from the calm (in comparison) business of incubating to the furious business of feeding tiny insatiable stomachs.

In a forthcoming Mother Jones article I'll be writing more about why this year may be the best for the Gulf's seabirds since the mid-19th century. 

(Photo �Julia Whitty.) 

Plus why it took me longer to get home than I imagined... part of my odyssey aboard a Mexican navy ship.

OCEAN BIRDS

American white pelican, Pelecanus erythrorhynchos. Photo by Manjith Kainickara via Wikimedia Commons.

Northern gannet, Morus bassanus. Photo by Andreas Trepte via Wikimedia Commons.

Great crested tern, Thalasseus bergii. Photo by Martin Pot (en:User:Martybugs) via Wikimedia Commons.

Atlantic Puffin, Fratercula arctica. Photo by Thomas O'Neil via Wikimedia Commons.

Blue-footed booby, Sula nebouxii. Photo by Rileypie via Wikimedia Commons.

Rockhopper penguin, Eudyptes chrysocome. Photo by Ben Tubby via Wikimedia Commons.

Spectacled eider, Somateria fischeri. Photo by Laura Whitehouse, courtesy USFWS, via Wikimedia Commons.

Long-tailed duck, Clangula hyemalis. Photo by Wolfgang Wander via Wikimedia Commons.

Penguin, via.

Unknown, via unknown (saltwater or fresh?).

Red phalarope, Phalaropus fulicarius. Photo by Andrei Taranchenko via Wikimedia Commons.

Smew, Mergellus albellus. Photo by Thermos via Wikimedia Commons.

White-faced storm-petrel, Pelagodroma marina. Photo by Aviceda via Wikimedia Commons.

Sanderlings, Calidris alba. Photo by Mbz1 via Wikimedia Commons.

Australasian gannets, Morus serrator, on the nest. Photo by Follash via Wikimedia Commons.

Common murres, Uria aalge, colony. Photo by Duncan Wright via Wikimedia Commons.

Ivory gull, Pagophila eburnea. Photo by jomilo75 via Wikimedia Commons.

Far eastern curlew, Numenius madagascariensis. Photo by 

Duncan Wright courtesy USFWS, via Wikimedia Commons.

UPDATE: WISDOM SURVIVED!

(Photo from Wild Encounters. Many other beauties here of albatross and the ever-lovely fairy terns. Well worth a visit.)

Many thanks to friends and readers who pointed out this BBC article reporting that Wisdom, a 60-year-old Laysan albatross mother, survived the tsunami that killed many thousands of birds on Midway Atoll. 

I'm guessing that Wisdom's part of the atoll wasn't submerged...? I'm hoping her chick survived too...?

Seems to me the world could use more Wisdom DNA.

DID THE TSUNAMI KILL "WISDOM?"

(Laysan albatross Wisdom, seen here with her chick at Midway Atoll, March 2011, before the tsunami. Credit: John Klavitter/U. S. Fish and Wildlife Service, via Wikimedia Commons.)

I've tweeted a few times of late about the remarkable Laysan albatross named Wisdom. She's at least 60 years old�the oldest-known wild bird in the US. 

A few months ago she returned to Midway Atoll in the northwestern Hawaiian Archipelago, found her mate, laid an egg, and recently hatched a chick. 

Now the Honolulu Star-Advertiser reports that tsunami waves from Japan's massive quake devastated Midway's seabird breeding rookeries, completely washing over one of the islands and partially submerging the other two. Tens of thousands of albatrosses died, adults and chicks. 

(Calculated wave height of the 2011 tsunami originating near Sendai, Japan.  Credit: NOAA.)

If you click on the image above you'll see the larger version, with the main Hawaiian Islands located in the center-right. The Hawaiian Archipelago tracks west-northwest from there, with Midway just visible near the far end of the island chain, embedded in the high-wave tsunami zone marked in red.

The albatross chicks on Midway were killed by the waves because none have fledged this early in the season. Laysan albatrosses have extremely long dependency periods�64 days of incubation, followed by 165 flightless days before they fledge and leave the island.

(Laysan albatross chicks with a few embedded adults, Midway Atoll. Credit: Mass Communication Specialist 2nd Class Mark Logico, US Navy, via Wikimedia Commons.) 

The adults were likely killed because they don't readily abandon their young.

Plus these are big birds of the open ocean. It takes them a long time to lumber across the water or the beach to get airborne. Midway's old runways turn out to be extremely useful for this purpose.

In the absence of wind, they can't takeoff or land. The Birds of North America Online describes their flight like this:

Depending on wind strength, take-off may be difficult, requiring a long run with the head outstretched, the bird flapping its wings and literally running. Take off from water is similar, requiring furious paddling with the webbed feet. Landings can be equally difficult, especially in birds that have been at sea for months, or in light winds. In the absence of the braking effort of a strong wind, landing birds may occasionally tumble on landing.

Midway is home to about 450,000 of the world's 590,926 breeding pairs of Laysan albatross. The IUCN Red List deems the species Near Threatened.

Some 25,300 black-footed albatrosses also live on Midway Atoll and presumably took some tsunami losses too.

(Black-footed albatross, Midway Atoll. Credit: Forest & Kim Starr, via Wikimedia Commons.)

Plus one pair of short-tailed albatrosses arrived this year. This species breeds on islands off Japan and China and is deemed Vulnerable by the IUCN Red List�with a total global population of only 2,364 individuals. 

A few months ago I tweeted the exciting news that this pair had appeared on Midway�an encouraging sign the species' range might be expanding.

Now, in the wake of the tsunami waves, US Fish and Wildlife officials have found one short-tailed albatross chick, returned it to a nesting area, and installed a remote-controlled camera to monitor it. But they haven't found the parents. 

(Short-tailed albatross. Credit: US Fish and Wildlife Service, via Wikimedia Commons.)

No word yet that I've heard on Wisdom's fate. This late in the breeding season few if any birds will try to lay another egg and start the long cycle again.

PRESTIGIOUS CONSERVATION AWARD GOES TO ENRIQUETA VELARDE

(Enriqueta Velarde [right] on Isla Rasa, 1980. Photo by Julia Whitty.)

Those of you who've read my book Deep Blue Home know of my great friendship with Enriqueta Velarde, a scientist at the University of Veracruz's Institute of Marine Sciences and Fisheries. We spent what was for me a profoundly formative field season together on tiny Isla Rasa in Mexico's Gulf of California, aka the Sea of Cortez, in 1980.

The island is home to nearly all the breeding Heermann's gulls and elegant terns on Earth. Their numbers have risen dramatically in recent decades thanks to Enriqueta's devotion and hard work. As I wrote in Deep Blue Home:

Enriqueta has returned to Rasa every spring to live among the birds. She has become one of the foremost voices for the preservation of the wild islands of the Gulf of California. Her presence, her deepening knowledge, have protected this corner of the world far beyond the modest funding she receives.

(Elegant tern, Sterna elegans. Photo by Regular Daddy, courtesy Wikimedia Commons.)
 
So I'm pleased to relay the good news that Enriqueta has been awarded the prestigious Volkswagen for the Love of the Planet Award (Programa Volkswagen, Por Amor al Planeta) for scientific investigation in the field of conservation biology.

From the awards page:

Over more than 30 years of scientific work Dr. Velarde has contributed significantly to the recovery of Rasa Island, one of the most unique ecosystems in the world, located in the Gulf of California... In the early seventies the population of gulls and terns amounted to a few tens of thousands. Today, as a result of the actions and the presence of Dr. Velarde, the number of birds that nest each year on the island is about half a million, its density is so high that have begun to nest on nearby islands.

�Felicidades, Enriqueta! I can't imagine anyone more deserving.

(Both shots are of the tern colony on Isla Rasa. Photos by Carl Safina. Thanks so much, Carl!)

ENDLESS SUMMER FOR SEABIRDS

(Streaked shearwater. Photo by marj k Marj Kibby, at Flickr.) 

Shearwaters are long-winged, strong-flying seabirds of the open ocean who come ashore only to breed. The rest of their lives�including the time between fledging and sexual maturity, up to 12 years in some species, maybe more�are spent entirely at sea. They're long-lived birds, with reports of one 55-year-old Manx shearwater still breeding in Ireland as of 2003.

Their time aloft and afloat is not without pattern. The more we learn, the more we see how these oceanic travellers follow vast systems of winds and waves across hemispheres and even oceans.

First up, there's an interesting paper out in the current issue of The Auk about a presumed foraging association between streaked shearwaters (Calonectris leucomelas) and skipjack tuna (Katsuwonus pelamis).

Foraging associations�as the term implies�are the result of a follower species (here, the shearwater) commonly following a nuclear species (here, the tuna) to capture prey flushed in the course of the nuclear's feeding or travels. The deep blue home is full of foraging associations... including the way savvy human fishers follow seabirds to find fish.

(Skipjack tuna. Photo JFontes�ImagDOP, from here.)

(Streaked shearwater at breeding colony on Mikura Island, Japan. Photo by Kanachoro, courtesy Wikimedia Commons.)

A little background: Streaked shearwaters breed on the islands and coastlines of Japan, China, and Korea, and make impressive winter migrations (=5,400 kilometers /3,300miles) to the waters off Vietnam, New Guinea, the Philippines, and Australia.

(Movement of a streaked shearwater from Japan to the Gulf of Carpentaria, Australia, between 16 October 2004 and 13 January 2005. Figure from Ornithological Science.)

In the figure above you can see the flight of one shearwater between its breeding grounds in the Northern Hemisphere during the boreal summer and its "wintering" grounds in the Southern Hemisphere during the austral summer. Those results are reported in a 2008 paper in Ornithological Science by some of the same members of the shearwater-skipjack team during an earlier phase of study.

(From Ornithological Science.)

In their latest investigations, the researchers attached small global location sensors to 48 breeding birds in 2006, 38 of whom returned the following year with their geolocators intact. Their findings, from the abstract:

Most Streaked Shearwaters wintered off northern New Guinea, an area of low primary productivity but high Skipjack Tuna (Katsuwonus pelamis) abundance. Streaked Shearwaters flew for longer periods and landed on the water more frequently around dawn and dusk during the wintering period. This pattern of activity is similar to that of subsurface predators such as tuna, and to that of tropical seabirds that are known to feed with subsurface predators. We suggest that Streaked Shearwaters probably forage in association with subsurface predators in the tropical oceans during the wintering period. Foraging in association with subsurface predators and morphological adaptations for gliding may allow Streaked Shearwaters to forage efficiently in both temperate and tropical environments.

(You might have to divert here to watch the video.)

This Blue Planet video shows the dynamics of shearwaters (not sure which species) working schools of mackerel herded up to the surface, initially by dolphins, then by skipjacks... I love the way they've mixed shearwater calls into the underwater video�dramatic, but inaccurate, at least to the extent heard here.

(Sooty shearwaters. Photo by marlin harms, courtesy Wikimedia Commons.)

In an incredible piece of scientific detective work a few years back, a different team of researchers found that another species, sooty shearwaters (Puffinus griseus), embarked on remarkable 64,000-kilometer/40,000-mile annual migrations through the entire basin of the Pacific Ocean from Antarctica to the Bering Sea�the longest migration of any animal tracked to that point.

(From PNAS.)

Their map shows the geolocation tracks of 19 of their tagged sooty shearwaters at New Zealand breeding colonies (light blue); their migration pathways north (yellow); and their wintering grounds and southward transits (orange). Figures b�d represent the figure-eight movement patterns of individual shearwaters travelling to one of three "winter" destinations in the North Pacific.

The authors suggest the figure-eight  pattern is facilitated by prevailing wind patterns and by the Coriolis effect�which influence the long-range trajectories of the birds as they rocket between hemispheres at rates of up to 910 kilometers/565 miles a day, and as they chase the waves of summer from one hemisphere to the other.

(Credit: NASA/Seasat.)

You can correlate something of the travels of the sooty shearwaters to this map of prevailing winds over the Pacific.

The 2006 sooty shearwater paper appeared in Proceedings of the National Academy of Sciences. From the abstract:

Electronic tracking tags have revolutionized our understanding of broad-scale movements and habitat use of highly mobile marine animals, but a large gap in our knowledge still remains for a wide range of small species. Here, we report the extraordinary transequatorial postbreeding migrations of a small seabird, the sooty shearwater, obtained with miniature archival tags that log data for estimating position, dive depth, and ambient temperature. Tracks (262 � 23 days) reveal that shearwaters fly across the entire Pacific Ocean in a figure-eight pattern while traveling 64,037 � 9,779 km roundtrip, the longest animal migration ever recorded electronically. Each shearwater made a prolonged stopover in one of three discrete regions off Japan, Alaska, or California before returning to New Zealand through a relatively narrow corridor in the central Pacific Ocean. Transit rates as high as 910 � 186 km�day^-1 were recorded, and shearwaters accessed prey resources in both the Northern and Southern Hemisphere�s most productive waters from the surface to 68.2 m depth.

But now the flying record of the sooty shearwaters been topped by a diminutive seabird, the Arctic tern, who not only crosses hemispheres but ocean basins as well.

(From PNAS.)

These are the geolocation tracks of 11 Arctic terns tracked from breeding colonies in Greenland and Iceland. The green lines are their autumn postbreeding migration (August�November). The red their "winter" range (December�March). The yellow their spring return migration (April�May). Two southbound migration routes are adopted in the South Atlantic, either (A) West African coast or (B) Brazilian coast. Dotted lines link locations during the equinoxes.

The research is reported in a February 2010 paper in PNAS, revealing migrations for Arctic terns of more than 80,000 kilometers/48,000 miles a year.

(Arctic tern. Photo by Malene Thyssen, courtesy Wikimedia Commons.)

Such globe-trotting transits keep these butterflies-of-the-sea hopped up on the endless summers of the high-latitudes. They barely know night.


The papers:

• Takashi Yamamoto, et al. At-Sea Distribution and Behavior of Streaked Shearwaters (Calonectris leucomelas) During the Nonbreeding Period. The Auk. 2010. 127 (4) 871�881. DOI: 10.1525/auk.2010.1002. 
• ? Akinori Takahashi. Post-breeding movement and activities of two Streaked Shearwaters in the north-western Paci?c. Ornithological Science. 2008. 7 (1) 29-35. DOI: 10.2326/osj.7.29. ?
• ? Scott A. Shaffer, et al. Migratory shearwaters integrate oceanic resources across the Pacific Ocean in an endless summer. PNAS. 2006. 103 ( 34) 12799-1280. DOI: 10.1073/pnas.0603715103. ?
• ? Carsten Egevang, et al. Tracking of Arctic terns Sterna paradisaea reveals longest animal migration. PNAS. 2010. 107 (5) 2078-2081. DOI: 10.1073/pnas.0909493107. ?

I ? open-access papers.