What Do Killer Whales Eat in the Arctic?

ScienceDaily (Jan. 29, 2012) — Killer whales (Orcinus orca) are the top marine predator, wherever they are found, and seem to eat everything from schools of small fish to large baleen whales, over twice their own size. The increase in hunting territories available to killer whales in the Arctic due to climate change and melting sea ice could seriously affect the marine ecosystem balance. New research published in BioMed Central's re-launched open access journal Aquatic Biosystems has combined scientific observations with Canadian Inuit traditional knowledge to determine killer whale behaviour and diet in the Arctic.

Orca have been studied extensively in the northeast Pacific ocean, where resident killer whales eat fish, but migrating whales eat marine mammals. Five separate ecotypes in the Antarctic have been identified, each preferring a different type of food, and similar patterns have been found in the Atlantic, tropical Pacific, and Indian oceans. However, little is known about Arctic killer whale prey preference or behaviour.

Traditional Ecological Knowledge (TEK) is increasingly being used to supplement scientific observations. Researchers from Manitoba visited 11 Canadian Nunavut Inuit communities and collated information from over 100 interviews with hunters and elders.

The Inuit reported that killer whales would 'eat whatever they can catch', mainly other marine mammals including seals (ringed, harp, bearded, and hooded) and whales (narwhal, beluga and bowhead). However there was no indication that Arctic killer whales ate fish. Only seven of the interviewees suggested that killer whales ate fish, but none of them had ever seen it themselves.

The type of reported prey varied between areas. Most incidents of killer whales eating bowhead whales occurred in Foxe Basin and narwhal predation was more frequent around Baffin Island. Inuit were also able to describe first-hand how killer whales hunted, including several reports of how killer whales co-operated to kill the much larger bowhead. During the hunt some whales were seen holding the bowhead's flippers or tail, others covering its blowhole, and others biting or ramming to cause internal damage. Occasionally dead bowheads, with bite marks and internal injuries but with very little eaten, are found by locals.

'Aarlirijuk', the fear of killer whales, influenced prey behaviour with smaller mammals seeking refuge in shallow waters or on shore and larger prey running away, diving deep, or attempting to hide among the ice. Even narwhal, which are capable of stabbing a killer whale with their tusks (although this is likely to result in the deaths of both animals), will run to shallow waters and wait until the whales give up.

Killer whales are seasonal visitors to the area and have recently started colonising Hudson Bay (possibly due to loss of summer sea ice with global warming). Local communities are reliant on the very species that the orcas like to eat. Dr Steven Ferguson from the University of Manitoba who led this research commented, "Utilising local knowledge through TEK will help scientists understand the effects of global warming and loss of sea ice on Arctic species and improve collaborative conservation efforts in conjunction with local communities."

http://www.sciencedaily.com/releases/2012/01/120129232818.htm

Like magic, Harry Potter's owl spotted across US

LAKE ANDES, S.D. (AP) — Famous for its role as Harry Potter's companion in the books and movies, a species of majestic, mostly white owls is being sighted in abundant numbers this winter far from both Hogwarts and its native Arctic habitat.

It's typical for snowy owls to arrive in the U.S. every three or four winters, but this year's irruption is widespread, with birders from the Pacific Northwest to New England reporting frequent sightings of the yellow-eyed birds. As many as 30 were spotted in December around South Dakota's Lake Andes.

"Thirty in one area, that's mind numbing," said Mark Robbins, an ornithologist with the University of Kansas Biodiversity Institute.

The arrival of the birds, which can top 2 feet in height with a wingspan of nearly 5 feet, is the result of a plentiful population of Arctic lemmings this summer, which led to a strong breeding season, said Denver Holt, director of the Owl Research Institute in Charlo, Mont.

Lemmings are snowy owls' main food source, and the baby boom is sending many of the youngsters across the border to scrounge for voles, field mice, rats, rabbits and shore birds.

"It's very unusual, because it's coast to coast," said Holt, who has been researching the owls' Arctic habitat for 25 years.

Snowy owls are drawn to frozen lakes, which remind them of their tundra back home in the Arctic, Robbins said.

"And if they're finding rodents there, they're staying there," he said. "And perhaps seeing a couple of more snowy owls there, they may think, 'OK, this is a hot spot.'"

The owls have been regular visitors to Boston's Logan Airport, and one even showed up just after Thanksgiving in Hawaii. Chicago's Montrose Point Bird Sanctuary has become a haven for the creatures, with "countless sightings" this season, said Matthew Cvetas, an Evanston, Ill., birder.

"It's just been really incredible," he said.

Cvetas said owl sightings are exciting for birders, as the creatures are mostly nocturnal and difficult to spot. Though snowy owls hunt day and night, the allure of their plumage helps make them a prize sighting.

"Here's the largest North American owl in terms of weight, a near all-white ghost of a bird for an adult male," said Cvetas, who has spotted four snowy owls since November. "For me, it symbolizes wilderness at its best."

Missouri and Kansas typically draw just a few snowy owls every three or four years, but reports this year have been widespread, Robbins said.

Birders spotted three snowy owls sitting on an irrigation unit west of Squaw Creek National Wildlife Refuge near Missouri's borders with Nebraska and Iowa, and there have been five of the birds hanging around Smithville Lake just outside of Kansas City.

"In Missouri, I don't think there's ever been two at a single site," he said.

People have always had a fascination with owls, but the book and 2001 film "Harry Potter and the Sorcerer's Stone," in which a snowy owl named Hedwig first appeared as Harry's companion and mail courier, thrust the species in the spotlight. Holt said the movie series helped land the winged creature a December 2002 National Geographic cover story.

"We were inundated with phone calls from people about all these kids wanting to have pet snowy owls," Holt said. "It just went crazy for a while there."

Snowy owls begin life with a mix of white and dark brown feathers. Males, which tend to be smaller, lose their dark feathers as they age, with many winding up pure white. Their lifespan is not known, but Holt estimates that snowy owls can likely survive 10 to 15 years in the wild and three decades in captivity.

There's no good estimate on the size of their population. Holt recalls a study in which researchers working on a Canadian island found thousands of snowy owls one year, only to follow up the next year to find not a single one.

"They're too spread out and they move around too much," Holt said.

Holt said snowy owls are remarkable predators, nearing flying speeds of 70 miles per hour with the ability to attack and eat creatures as large as Canada geese and great blue herons. Yet despite that diverse diet, their breeding seems dependent on a single food source — the Arctic lemming.

He said this year's influx is following in Harry Potter's footsteps to return the snowy owl into the public spotlight, which is great for the species and his research.

"It's wonderful," Holt said. "It's great for snowy owls. It's great PR."

http://www.google.com/hostednews/ap/article/ALeqM5gzVbbLZXqxf-7Jrq9VCEZR0T4K6A?docId=06beaec5b2c14199b566ecfac40d08b1

Whales take Northwest Passage as Arctic sea-ice melts

Bowhead whales, the giants of the Arctic, are using the Northwest Passage to move across the top of the Americas.

Skeletons, DNA samples and harpoon heads have all suggested that bowhead populations living on each side of the continent did meet and mingle.

Now, research published in the journal Biology Letters has used satellite tags to provide confirmation.

The work may provide insights into the development of Arctic cultures in which bowhead hunting plays a central role.

Mads Peter Heide-Jorgensen from the Greenland Institute of Natural Resources led a team that has satellite-tagged more than 100 bowheads over the last decade - much of the work funded by oil and gas companies interested in the Arctic's new mineral wealth.

Last August, as the Arctic sea ice neared its annual minimum, the satellite data told them that one whale from the Greenland side and one from the Alaskan side had arrived in pretty much the same area, north of the Canadian mainland.

They spent about 10 days circling in the same patch of water before heading back to their respective home ranges.

This is the first time such mingling has been seen directly, although there is plenty of circumstantial evidence that it has happened sporadically in the past.

Bowhead skeletons are found on elevated beaches through the Canadian archipelago. In 19th Century Alaska, whales were caught containing tips of harpoons that had been thrown by whalers in the Atlantic.

Passage may have been easier in the last four summers than in preceding decades, as the Arctic ice has shrunk to a smaller size than at any time in the satellite record.

"I'm pretty sure that the low sea ice in the summer has triggered this migration through this area," Dr Heide-Jorgensen told BBC News.

"I'm pretty sure that when it occurred in the past, when we got all these skulls on the beach, that was during a warm period.

"During any climatic period, there could have been years with less ice in the Northwest Passage; and I'm pretty sure the bowheads can find cracks [in the ice] that are too small to show up on satellite images."

Whaling route

The other fascinating line of evidence for bowhead migration along northern Canada lies in the human societies that depend on the whales, where communities are structured around the process of whaling.

The best known example today are the Inupiat of Alaska.

They are descended from the Thule culture, which appears to have emerged in Alaska about 1,000 years ago.

Thule people spread across Canada to Greenland in the three centuries following.

They ate meat and blubber from the bowhead, built houses using their bones and burned their oil.

Given their dependence on the single species, could they have made the migration without access to the whales?

Anne Jensen, an archaeologist who has lived in the northern Alaskan town of Barrow for many years and is a leading authority on the Thule people, said the routes taken by the two whales last year passed close by sites that date the Thule expansion.

"This supports the idea that the expansion was connected to whaling," she told BBC News.

"People were moving - presumably after having done some small-group exploring that is archaeologically invisible - to places where they knew whales went, perhaps in a period when the ice cover was reduced for some reason.

"Certainly, they were not settling in places where whales weren't available at that point.

"Since the Thule seem to have been able to hunt whales from the ice at leads, it doesn't mean that there was an ice-free Northwest Passage - just one that bowheads could get through, with enough leads for hunters to see and catch the whales."

Of all the great whales, the bowheads are the best adapted to life in the harsh Arctic environment, with a domed bony head that can force a way through relatively thin sheets of ice, and a thick layer of blubber.

"They have their lunch package on them - they can move for months without eating because they have blubber almost half a metre thick, so so they can move through the Northwest Passage without eating," said Dr Heide-Jorgensen.

Genetic evidence also suggests that in periods past, bowheads also moved along the northern coast of Siberia.

They do not have a set migration pattern, unlike some other whale species - which raises questions about how they may adapt in future, if the projected declines in summer Arctic sea ice materialise.

"I'm sure they will be going all over the area when there's open water," said Dr Heide-Jorgensen.

"They're capable of moving relatively long distances in a short period of time, and they can venture into areas where we haven't seen them for a very long time - so I'm sure they will use the open water if the ice disappears."

The one question mark would be over their food supply, with major changes in Arctic sea ice likely to disrupt food webs that include the swarms of copepods (tiny crustaceans) that are the key ingredient of their diet.
By Richard Black Environment correspondent, BBC News
http://www.bbc.co.uk/news/science-environment-14976344

Mating Mystery: Hybrid Animals Hint at Desperation in Arctic

(sk) Mating Mystery: Hybrid Animals Hint at Desperation in Arctic


An odd-looking white bear with patches of brown fur was shot by hunters in 2006 and found to be a cross between a polar bear and a grizzly bear. Apparently, grizzlies were moving north into polar bear territory. Since then, several hybrid animals have appeared in and around the Arctic, including narwhal-beluga whales and mixed porpoises.

The culprit may be melting Arctic sea ice, which is causing barriers that once separated marine mammals to disappear, while the warming planet is making habitats once too cold for some animals just right. The resulting hybrid creatures are threatening the survival of rare polar animals, according to a comment published today (Dec. 15) in the journal Nature. [ Real of Fake? 8 Bizarre Hybrid Animals]

A team led by ecologist Brendan Kelly of the National Marine Mammal Laboratory counted 34 possible hybridizations between distinct populations or species of Arctic marine mammals, many of which are endangered or threatened.

"The greatest concern is species that are already imperiled," said Kelly, first author of the Nature comment. "Interbreeding might be the final straw."

Pizzlies and Narlugas
When hunters encountered a hybrid of a polar bear and a grizzly in 2006, Kelly's colleagues remarked that the incident was just a fluke. But as Kelly delved into the issue, he found more evidence of similar anomalies. In 2009, a cross between a bowhead and a right whale was spotted in the Bering Sea, between Alaska and Russia. And a museum specimen in Alaska attests to breeding between spotted seals (Phoca largha) and ribbon seals (Histriophoca fasciata), which belong to different genera, a scientific classification of organisms that is broader than the species level.

Evidence suggests at least five other types of hybrids that may arise from animals of distinct genera, Kelly's team reported. These include:

* Narwhal (Monodon monoceros ) and beluga whale (Delphinapterus leucas)

* Ringed seal (Phoca hispida) and ribbon seal (Histriophoca fasciata)

* Bowhead whale (Balaena mysticetus) and right whale (Eubalaena spp.)

* Harp seal (Phoca groenandica) and hooded seal (Cystophora cristata)

* Harbour porpoise (Phocoena phocoena) and Dall's porpoise (Phocoenoides dalli)

Breedings between these marine mammals near the North Pole are likely to result in fertile offspring, because many of these animals have the same number of chromosomes, said comment co-author Andrew Whiteley, a conservation geneticist at the University of Massachusetts, Amherst.

Chromosomes that are unmatched in number cannot pair during meiosis, a special type of cell division necessary for sexual reproduction. During meiosis, chromosomes duplicate and the cell divides to form daughter cells, which split apart to form gametes, or mature sexual reproductive cells. But with unmatched chromosomes, the split into gametes would be uneven, creating sterility.

Over the short term the hybrid offspring from these Arctic animal matings will likely be strong and healthy, because unlike inbreeding, which magnifies deleterious genes, so-called outbreeding can mask these genes. Most of these genes are recessive, meaning the offspring need a pair to actually show the trait. Different species or different genera generally don't have the same bad recessive alleles, and so there's not a high chance of a pair turning up. (Alleles are different versions of the same gene.)

But over time, as the hybrids mate randomly, those harmful genes will come out of hiding and make the offspring less fit and less capable of surviving, Whiteley warned.

Kelly said that breeding between species usually isn't beneficial when it's caused by accelerated environmental change, because the hybrid animals don't have time to evolve survival traits. "This change is happening so rapidly that it doesn't bode well for adaptive responses."

http://www.livescience.com/animals/hybrid-animals-arctic-climate-101215.html

Mating Mystery: Hybrid Animals Hint at Desperation in Arctic

(sk) Mating Mystery: Hybrid Animals Hint at Desperation in Arctic


An odd-looking white bear with patches of brown fur was shot by hunters in 2006 and found to be a cross between a polar bear and a grizzly bear. Apparently, grizzlies were moving north into polar bear territory. Since then, several hybrid animals have appeared in and around the Arctic, including narwhal-beluga whales and mixed porpoises.

The culprit may be melting Arctic sea ice, which is causing barriers that once separated marine mammals to disappear, while the warming planet is making habitats once too cold for some animals just right. The resulting hybrid creatures are threatening the survival of rare polar animals, according to a comment published today (Dec. 15) in the journal Nature. [ Real of Fake? 8 Bizarre Hybrid Animals]

A team led by ecologist Brendan Kelly of the National Marine Mammal Laboratory counted 34 possible hybridizations between distinct populations or species of Arctic marine mammals, many of which are endangered or threatened.

"The greatest concern is species that are already imperiled," said Kelly, first author of the Nature comment. "Interbreeding might be the final straw."

Pizzlies and Narlugas
When hunters encountered a hybrid of a polar bear and a grizzly in 2006, Kelly's colleagues remarked that the incident was just a fluke. But as Kelly delved into the issue, he found more evidence of similar anomalies. In 2009, a cross between a bowhead and a right whale was spotted in the Bering Sea, between Alaska and Russia. And a museum specimen in Alaska attests to breeding between spotted seals (Phoca largha) and ribbon seals (Histriophoca fasciata), which belong to different genera, a scientific classification of organisms that is broader than the species level.

Evidence suggests at least five other types of hybrids that may arise from animals of distinct genera, Kelly's team reported. These include:

* Narwhal (Monodon monoceros ) and beluga whale (Delphinapterus leucas)

* Ringed seal (Phoca hispida) and ribbon seal (Histriophoca fasciata)

* Bowhead whale (Balaena mysticetus) and right whale (Eubalaena spp.)

* Harp seal (Phoca groenandica) and hooded seal (Cystophora cristata)

* Harbour porpoise (Phocoena phocoena) and Dall's porpoise (Phocoenoides dalli)

Breedings between these marine mammals near the North Pole are likely to result in fertile offspring, because many of these animals have the same number of chromosomes, said comment co-author Andrew Whiteley, a conservation geneticist at the University of Massachusetts, Amherst.

Chromosomes that are unmatched in number cannot pair during meiosis, a special type of cell division necessary for sexual reproduction. During meiosis, chromosomes duplicate and the cell divides to form daughter cells, which split apart to form gametes, or mature sexual reproductive cells. But with unmatched chromosomes, the split into gametes would be uneven, creating sterility.

Over the short term the hybrid offspring from these Arctic animal matings will likely be strong and healthy, because unlike inbreeding, which magnifies deleterious genes, so-called outbreeding can mask these genes. Most of these genes are recessive, meaning the offspring need a pair to actually show the trait. Different species or different genera generally don't have the same bad recessive alleles, and so there's not a high chance of a pair turning up. (Alleles are different versions of the same gene.)

But over time, as the hybrids mate randomly, those harmful genes will come out of hiding and make the offspring less fit and less capable of surviving, Whiteley warned.

Kelly said that breeding between species usually isn't beneficial when it's caused by accelerated environmental change, because the hybrid animals don't have time to evolve survival traits. "This change is happening so rapidly that it doesn't bode well for adaptive responses."

http://www.livescience.com/animals/hybrid-animals-arctic-climate-101215.html

Polar bears can't eat geese into extinction

New statistical model demonstrates that trophic mismatch feeds bears without exterminating snow geese

As the Arctic warms, a new cache of resources—snow goose eggs—may help sustain the polar bear population for the foreseeable future. In a new study published in an early online edition of Oikos, researchers affiliated with the Museum show that even large numbers of hungry bears repeatedly raiding nests over many years would have a difficult time eliminating all of the geese because of a mismatch in the timing of bear arrival on shore and goose egg incubation.

"There have been statements in popular literature indicating that polar bears can extirpate snow geese quickly once they start to eat eggs," says Robert Rockwell, a research associate in the Division of Vertebrate Zoology at the Museum and a professor at the City University of New York. "However, there will always be the occasional mismatch in the overlap between the onshore arrival of bears and the incubation period of the geese. Even if the bears eat every egg during each year of complete 'match,' our model shows that periodic years of mismatch will provide windows of successful goose reproduction that will partially offset predation effects."

In the last few years, work along the Cape Churchill Peninsula of western Hudson Bay by Rockwell and colleagues has suggested that polar bears are not as hamstrung by their environment as many biologists believe. One new nutritional option for polar bears is the bounty of goose eggs which had previously hatched into goslings that were gone by the time bears came ashore. In recent years, 'early' bears have left breaking sea ice to come ashore and consume eggs. In fact, the earlier the bears come ashore, the better: eggs are higher in nutrients when the embryo is younger.

In the new Oikos paper, Rockwell and coauthors Linda Gormezano (also affiliated with the Museum) and David Koons (a researcher at Utah State University in Logan) simulated the timing of events during the Arctic spring: the break-up of sea ice, the movement of bears onto shore, the migration of geese to the North, and the laying of eggs. Results from the computer model show that the mismatch of timing is something that both the bears and geese can use to their advantage. The timing of geese migration is primarily based on photoperiod (the amount of light in 24 hours), which will not change as quickly as polar bear movements, which are based on the melting of sea ice.

Results show that the advance in mean overlap of the two species gives an advantage to polar bears. But increased variability, also the result of global climate change, leads to an increased mismatch that is good news for snow geese.

"Mismatch is often thought to be bad, but in this case periodic mismatch is good because it keeps geese from going extinct and allows polar bears to eat," says Rockwell. "Are polar bears adaptable? Of course. This could be a nice stable system. The geese aren't going to go away, and they are a nutrient resource for the bears."

http://www.eurekalert.org/pub_releases/2010-11/amon-pbc110410.php

Polar bears can't eat geese into extinction

New statistical model demonstrates that trophic mismatch feeds bears without exterminating snow geese

As the Arctic warms, a new cache of resources—snow goose eggs—may help sustain the polar bear population for the foreseeable future. In a new study published in an early online edition of Oikos, researchers affiliated with the Museum show that even large numbers of hungry bears repeatedly raiding nests over many years would have a difficult time eliminating all of the geese because of a mismatch in the timing of bear arrival on shore and goose egg incubation.

"There have been statements in popular literature indicating that polar bears can extirpate snow geese quickly once they start to eat eggs," says Robert Rockwell, a research associate in the Division of Vertebrate Zoology at the Museum and a professor at the City University of New York. "However, there will always be the occasional mismatch in the overlap between the onshore arrival of bears and the incubation period of the geese. Even if the bears eat every egg during each year of complete 'match,' our model shows that periodic years of mismatch will provide windows of successful goose reproduction that will partially offset predation effects."

In the last few years, work along the Cape Churchill Peninsula of western Hudson Bay by Rockwell and colleagues has suggested that polar bears are not as hamstrung by their environment as many biologists believe. One new nutritional option for polar bears is the bounty of goose eggs which had previously hatched into goslings that were gone by the time bears came ashore. In recent years, 'early' bears have left breaking sea ice to come ashore and consume eggs. In fact, the earlier the bears come ashore, the better: eggs are higher in nutrients when the embryo is younger.

In the new Oikos paper, Rockwell and coauthors Linda Gormezano (also affiliated with the Museum) and David Koons (a researcher at Utah State University in Logan) simulated the timing of events during the Arctic spring: the break-up of sea ice, the movement of bears onto shore, the migration of geese to the North, and the laying of eggs. Results from the computer model show that the mismatch of timing is something that both the bears and geese can use to their advantage. The timing of geese migration is primarily based on photoperiod (the amount of light in 24 hours), which will not change as quickly as polar bear movements, which are based on the melting of sea ice.

Results show that the advance in mean overlap of the two species gives an advantage to polar bears. But increased variability, also the result of global climate change, leads to an increased mismatch that is good news for snow geese.

"Mismatch is often thought to be bad, but in this case periodic mismatch is good because it keeps geese from going extinct and allows polar bears to eat," says Rockwell. "Are polar bears adaptable? Of course. This could be a nice stable system. The geese aren't going to go away, and they are a nutrient resource for the bears."

http://www.eurekalert.org/pub_releases/2010-11/amon-pbc110410.php