Extreme Snowstorms Disrupt Antarctic Seabird Breeding
Antarctic seabirds suffer devastating breeding failure as violent snowstorms sweep through vital colonies, raising urgent questions about climate-induced extremes.
Entire Populations of Antarctic Birds Fail to Breed Amid Extreme Snowstorms
In the austral summer of 2021-22, Antarctica witnessed a dramatic and alarming event: entire populations of seabirds, including Antarctic petrels, snow petrels, and south polar skuas, failed to breed in some of the continent’s most vital bird colonies. The culprit was an unprecedented series of violent snowstorms that swept across these regions, altering the very fabric of their fragile ecosystems and highlighting the increasing threats posed by a warming planet.
The Antarctic Breeding Cycle: A Delicate Balance
Each year, as the Southern Hemisphere enters its summer, hundreds of thousands of seabirds migrate to the Antarctic interior to breed. Antarctic petrels, snow petrels, and south polar skuas are adapted to the region’s extreme conditions and time their arrival for when bare patches of ground emerge, suitable for nesting and egg laying. Typically, eggs are laid in November and December, with the young birds hatching and maturing enough to fledge by late February or March.
- Antarctic Petrel: Known for nesting on rocky, snow-free outcrops.
- Snow Petrel: Similarly reliant on exposed nesting grounds, mostly free from deep snow.
- South Polar Skua: Both a predator and scavenger, often preying on the eggs and chicks of other birds.
Over recent decades, colonies such as Svarthamaren and Jutulsessen in Dronning Maud Land have served as major strongholds for these species. Svarthamaren, for instance, regularly hosted between 20,000 and 200,000 Antarctic petrel nests, up to 2,000 snow petrel nests, and a hundred or more skua nests each breeding season.
Devastation Unleashed: The 2021-22 Snowstorms
During the 2021-22 breeding season, researchers monitoring these colonies noticed something extraordinary—and distressing. Violent snowstorms struck Dronning Maud Land in December and January, blanketing the landscape in deep, persistent snow. Areas that were typically clear and ideal for nesting remained inaccessible for months. Bird biologists, led by Sébastien Descamps of the Norwegian Polar Institute, documented an event virtually unseen in decades of study: almost complete breeding failure across multiple species and sites.
- In Svarthamaren, researchers counted only three Antarctic petrel nests—a collapse from the tens or hundreds of thousands normally present.
- Snow petrels and south polar skuas showed similar devastation, with nearly all potential breeding activity halted.
- Nearby Jutulsessen also saw a total absence of Antarctic petrel nests, while previous years consistently supported vast colonies.
This was no isolated incident. The snowstorms impacted bird colonies spread across hundreds of kilometers, meaning a significant proportion of the global populations of these species failed to reproduce that year.
Table: Breeding Activity Before and After 2021-22 Snowstorms
| Colony | Species | Typical Nests (pre-2021) | 2021-22 Season |
|---|---|---|---|
| Svarthamaren | Antarctic Petrel | 20,000-200,000 | 3 |
| Svarthamaren | Snow Petrel | ~2,000 | Handful |
| Svarthamaren | South Polar Skua | >100 | 0 |
| Jutulsessen | Antarctic Petrel | Tens of thousands | 0 |
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Why Were the Birds Unable to Breed?
Unlike many bird species that nest in trees or shrubs, these Antarctic seabirds require bare ground to lay their eggs. When snow covers the landscape throughout the summer, the birds cannot access suitable nesting sites. The snow cover in 2021-22 was far deeper and more prolonged than usual, making it impossible for birds to even attempt reproduction. The birds also faced increased energetic costs from sheltering against harsh winds and freezing conditions, further reducing the chances of successful breeding.
- Loss of Accessible Nesting Sites: Snow accumulation made ground inaccessible throughout the breeding season.
- Energetic Stress: Birds expended precious reserves sheltering, keeping warm, and surviving rather than caring for eggs or chicks.
- Ecological Cascades: In the absence of Antarctic petrels’ eggs and chicks, south polar skuas—predatory birds that depend on these food sources—were also unable to breed.
The Climate Connection: Attributing Extreme Events
While Antarctica has long been seen as relatively isolated from direct climate impacts (except for the warming Antarctic Peninsula), recent years have upended that narrative. Human-driven climate change is increasing the frequency and severity of extreme weather events on the continent:
- Increased Snowfall: Warmer air holds more moisture, leading to heavier snowfall events.
- Stronger Storms: Shifting climate dynamics have intensified polar wind and storm patterns.
- Climate Models: Projections suggest that such storms will only become more common if greenhouse gas emissions are not curbed.
The study’s lead author, Sébastien Descamps, emphasized, “We know that in a seabird colony, when there’s a storm, you will lose some chicks and eggs, and breeding success will be lower. But here we’re talking about tens if not hundreds of thousands of birds, and none of them reproduced throughout these storms. Having zero breeding success is really unexpected.”
Ecological and Population Implications
For long-lived seabirds like petrels and skuas, a single year of failed breeding does not necessarily mean immediate catastrophe. These birds can live for 15-25 years, providing them multiple opportunities to breed successfully over their lifespans. However, the scale and geographic extent of the 2021-22 breeding failure is deeply concerning to researchers.
- If such failures become more frequent due to climate change, populations may decline over time.
- Loss of breeding for even a single season is a warning signal about the vulnerability of Antarctic wildlife to extreme events.
- Species interactions—such as the reliance of skuas on petrel eggs and chicks—could exacerbate cascading population impacts.
As Heather J. Lynch, a conservation biologist not involved in the study, noted: “They can cope, but if the frequency of these breeding failures increases, then we will expect that the colonies will diminish in the long run.”
Ongoing Research and Monitoring Efforts
The 2021-22 breeding failure in Dronning Maud Land has renewed calls for expanded monitoring and further research into Antarctic bird populations and the broader impacts of climate change on polar regions. Improved models are needed to better predict storm severity and snow accumulation. Existing data gaps, especially around snow measurements at bird colonies, hinder scientists’ ability to fully explain and anticipate future impacts.
- Long-term monitoring of key colonies is critical to detect population trends and shifts.
- Better integration of weather, snow, and climate modeling will help forecast future breeding seasons.
- International cooperation is required, as many Antarctic species cross national boundaries.
Researchers are also learning from similar events affecting other iconic polar species, such as emperor penguins, whose breeding success depends on the stability of sea ice. The growing evidence for regional breeding failures underscores the urgency of mitigating climate change and safeguarding polar habitats.
Frequently Asked Questions (FAQs)
Q: Why do Antarctic seabirds require bare ground for nesting?
A: Species like Antarctic petrels, snow petrels, and south polar skuas nest directly on bare ground or rocks, as deep snow prevents them from accessing suitable sites to lay eggs and raise their chicks.
Q: How common are total breeding failures among Antarctic seabirds?
A: While localized failures in breeding can occur after major storms, the near-total breeding collapse across multiple large colonies in 2021-22 was unprecedented and extremely rare.
Q: Is this linked to climate change?
A: Yes, researchers attribute the unusual frequency and intensity of snowstorms to human-driven climate change, which is causing warmer, wetter weather systems and more intense storms across Antarctica.
Q: Do Antarctic seabird populations face extinction from such events?
A: A single year of breeding failure is not likely to cause extinction, as these birds have long lifespans. However, repeated events of this scale could severely threaten population persistence over time.
Q: What can be done to protect Antarctic seabirds?
A: Protecting these birds ultimately requires addressing global climate change through emissions reductions, improving climate and environmental monitoring, and enacting conservation measures in vulnerable habitats.
Conclusion: A Call to Action for Antarctic Conservation
The devastating breeding failure of Antarctic petrels, snow petrels, and south polar skuas in the wake of extreme snowstorms serves as a stark reminder of the continent’s vulnerability to rapid environmental change. These events not only disrupt intricate polar ecosystems but also foreshadow the escalating impacts of climate change on the world’s most remote and delicate habitats. As scientific understanding grows and data collection intensifies, the urgent need for global climate action and robust conservation strategies becomes ever more apparent—for Antarctica’s wildlife and, ultimately, for the planet at large.
References
- https://www.sciencedaily.com/releases/2023/03/230313121000.htm
- https://www.smithsonianmag.com/smart-news/strong-snowstorms-prevented-tens-of-thousands-of-antarctic-seabirds-from-breeding-180981861/
- https://www.nhm.ac.uk/discover/news/2023/march/extreme-snowstorms-decimate-antarctic-petrel-nests.html
- https://www.nature.com/articles/s43247-023-00927-x
- https://gosharpener.com/blogs/404403/Entire-Populations-of-Antarctic-Birds-Failed-to-Breed-Last-Year
- https://polarjournal.net/a-bird-thats-an-emperor-in-name-only/
- https://www.newswise.com/articles/entire-populations-of-antarctic-seabirds-fail-to-breed-due-to-extreme-climate-change-related-snowstorms
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