The Arctic ecosystem is defined by extreme seasonality and a brief, intense summer, supporting vast breeding colonies of seabirds like Thick-billed Murres, Little Auks, and Puffins. These birds congregate on remote cliffs and islands to nest. This makes them a dense, predictable, and highly caloric food source in a resource-scarce environment. The presence of millions of seabirds forms a crucial trophic link, transferring energy from the polar seas to terrestrial and marine predators. This influx of life attracts specialized hunters adapted to exploit this seasonal bounty.
Avian Predators of Arctic Seabirds
The skies above the nesting cliffs are often dominated by other avian species, notably Skuas (Jaegers). These birds employ kleptoparasitism, aggressively pursuing smaller seabirds like Puffins and Murres until they drop or regurgitate the fish they are carrying. The relentless aerial chases force the victim to abandon its meal, which the Jaeger then snatches. This piracy is a primary feeding method, particularly for the migratory Arctic Skua.
Larger gulls, especially the Glaucous Gull, are formidable, opportunistic predators and scavengers within the breeding colonies. These imposing birds regularly patrol the colony edges, preying on unattended eggs and newly hatched chicks. Glaucous Gulls ambush adult birds, such as Dovekies, or seize small chicks whole, sometimes taking down adult Kittiwakes. Their predatory pressure increases significantly during periods of disturbance, which flushes protective adults and exposes vulnerable nests.
Terrestrial and Coastal Mammalian Hunters
Mammalian predators pose a significant threat to seabird colonies, particularly those accessing nesting sites via land or temporary sea ice. The Arctic Fox is a highly adapted hunter known for devastating raids, often caching hundreds of eggs and chicks. Foxes are proficient at digging out burrows and crevices where Puffins and storm petrels nest, directly targeting the birds and their young. A single fox accessing an isolated colony can cause mass abandonment and near-total breeding failure for vulnerable ground-nesting species.
The Polar Bear is another substantial, opportunistic terrestrial predator whose impact is becoming more pronounced. As sea ice melts earlier due to climate change, bears are forced onto land for longer periods, seeking alternative food sources like seabird eggs. They commonly target large, accessible eggs from species such as Common Eiders and various geese, often crushing the shells and lapping up the contents. These raids can result in the rapid destruction of entire nesting colonies and near-total reproductive failure.
While seals remain the primary prey, Polar Bears also opportunistically consume adult seabirds and fledglings near shorelines or ice floes. This shift highlights a cascade effect in the Arctic food web, where a marine apex predator relies increasingly on terrestrial food during the ice-free season. The presence of these large mammals causes direct mortality and wide-scale panic, leading to eggs cooling and chicks being exposed to smaller scavengers.
Marine Predators Targeting Seabirds
The water column and surface host predators that ambush seabirds while they are fishing or resting. Orcas, or Killer Whales, are apex marine predators increasingly observed in Arctic waters due to diminishing sea ice. While Orcas primarily hunt marine mammals, seabirds are a known, minor component of their diet. They have been documented preying on flightless species, such as Murre fledglings, and occasionally large gulls, often attacking from below the surface.
Orcas, particularly transient ecotypes, sometimes engage in behaviors that appear to be harassment or play rather than strictly hunting for food. They may slap birds with their tail flukes or mouth them without consuming the carcass, especially with juveniles. This behavior, which may be hunting practice for young whales, can still be lethal to the targeted seabirds. Large seals like the Ringed or Bearded Seal are common but are primarily fish and invertebrate eaters, and are not considered significant predators of Arctic seabirds.