A single polar bear destroyed 89% of an entire ‘eider bird colony’ on an Alaskan barrier island in less than a day, giving scientists a striking example of how a changing Arctic is altering relationships between predators and seabirds.
asserted
Arctic → destroy → predators
The incident, recorded on Spy Island in July 2024, was part of a wider pattern described in a 2026 study published in ‘
Norwegian Polar Institute.’
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incident → record → Institute
Researchers found that polar bear attacks on bird colonies have become more noticeable as summer sea ice declines, leaving bears with less access to the seals they traditionally hunt.
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they → find → seals
Instead, some bears are spending more time on land and turning to eggs, chicks and birds for food.
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bears → spend → food
The discovery is important because such predation was once rare in northern Alaska, but is now adding pressure to seabirds already facing other climate-related problems there.
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predation → add → problems
What happened to the seabird colony of the Alaskan island
The remarkable incident took place on Spy Island, a 58-hectare barrier island in the Beaufort Sea, about 6 kilometres from the mainland coast and the Colville River delta.
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incident → happen → coast
The island has been monitored periodically since 1983 because it provides important nesting habitat for common eiders and other marine and waterbirds.
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it → monitor → eiders
According to the study, researchers surveyed the colony on 7 July 2024 and recorded nesting attempts by common eiders, glaucous gulls and other birds.
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researchers → accord → eiders
Time-lapse cameras later captured a polar bear moving through the colony and feeding on eggs.
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bear → capture → eggs
That single bear destroyed 89% of the common eider nests in less than a day.
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bear → destroy → day
The researchers described the event as evidence of a rapid change in predation pressure on Arctic seabirds.
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researchers → describe → seabirds
The findings were also highlighted by BBC Wildlife, which reported that the bear consumed hundreds of eggs and that the attack represented an unusually destructive event for an Alaskan seabird colony.
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attack → highlight → colony
Why are polar bears eating seabirds instead of seals
Polar bears are traditionally associated with hunting seals from sea ice.
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bears → eat → ice
As summer sea ice becomes thinner and disappears for longer periods, bears are increasingly spending time on land.
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bears → become → land
The Polar Research study explains that the loss of summer sea ice reduces polar bears’ access to their traditional seal prey.
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loss → explain → prey
This can push them towards alternative sources of food along Alaska’s coast, including seabird colonies.
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This → push → colonies
For a hungry polar bear, a nesting colony offers an unusually concentrated food source.
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colony → nest → source
Eggs, chicks and adult birds are gathered in one relatively small area, meaning a bear can find large amounts of food without having to travel far.
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bear → gather → food
BBC Wildlife reported that shrinking sea ice is forcing more bears ashore on Alaska’s barrier islands and mainland coastline.
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ice → report → islands
Once there, some are turning to seabird eggs, nestlings and, occasionally, adult birds.
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some → turn → eggs
The behaviour does not mean polar bears have suddenly changed into specialist bird hunters.
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bears → mean → hunters
Rather, the researchers see it as an example of animals adjusting their feeding behaviour as their environment changes.
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environment → see → behaviour
Has this happened before in Alaska
Polar bears have eaten seabirds elsewhere in the Arctic, but the behaviour had historically been uncommon in northern Alaska.
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behaviour → happen → Alaska
The long record from ‘Cooper Island’ provides a useful comparison.
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record → provide → comparison
Researchers have studied a colony of Mandt’s black guillemots there for decades.
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Researchers → study → decades
Between 1975 and 2007, polar bear predation occurred in only nine of 33 years and affected less than 3% of nests.
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predation → occur → nests
That changed between 2008 and 2010.
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That → change → 2008
During those three years, bears disturbed 38% of the nests, while 43% of the 423 guillemot nestlings that hatched were consumed.
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that → disturb → nestlings
Researchers attempted to protect the birds in 2011 by replacing wooden nest sites with modified plastic carrying cases designed to resist bears.
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Researchers → attempt → bears
The measure initially worked.
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measure → work → ?
After 2020, however, bears became increasingly capable of manipulating the protective structures, sometimes ejecting eggs, chicks or adult birds.
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bears → become → eggs
By 2024-25, polar bear predation had resulted in ‘complete reproductive failure’ at the Cooper Island colony.
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predation → result → colony
The impact could be serious because seabirds are already facing other difficulties linked to a changing Arctic.
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seabirds → face → Arctic
The research study notes that these birds are dealing with reduced food availability as well as nesting habitat that can be flooded or eroded.
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that → note → availability
Additional predation from polar bears therefore adds another source of pressure during the breeding season.
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predation → add → season
At Cooper Island, the timing of bear visits has also changed.
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timing → change → visits
Earlier observations largely involved bears arriving during August, when chicks were being raised.
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chicks → involve → August
More recently, bears have appeared in June and July, when adult guillemots are incubating eggs or caring for young.
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guillemots → appear → young
That earlier arrival gives bears access to nests at a particularly vulnerable stage.
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arrival → give → stage
The researchers recorded three adult guillemots killed by bears in each of the 2024 and 2025 breeding seasons.
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researchers → record → seasons
…and 13 more, not listed.
The Aporia
