Atlantic puffins are classified as Vulnerable by the International Union for Conservation of Nature, one step below Endangered, after their global population dropped sharply in recent decades. Tufted puffins and horned puffins in the North Pacific have also seen steep regional declines. The threats driving these losses are varied but interconnected, with warming oceans disrupting the fish puffins depend on, industrial fishing depleting prey stocks, gillnet bycatch killing birds directly, and emerging dangers like plastic pollution, avian influenza, and artificial light compounding the pressure. No single factor tells the whole story, and the interplay between them is what makes puffin conservation so challenging.
A Collapsing Food Supply
The most consequential threat to puffins is the decline in the small schooling fish they eat, particularly sandeels and capelin. Puffins are specialist feeders during the breeding season. They need to catch dozens of small fish per day to keep a growing chick alive, ferrying mouthfuls of fish back to the burrow over weeks. When those fish become scarce or shift in timing or location, breeding colonies can fail almost entirely.
In Iceland, home to roughly sixty percent of the world’s Atlantic puffins, ocean warming has disrupted the biology of the lesser sandeel, the species’ principal prey. Sandeels need to reach a minimum body size before winter to survive, and that size threshold rises as water temperatures climb. Warmer winters also cause sandeels to develop smaller reproductive organs, reducing the next generation’s numbers. Research spanning more than a century of Icelandic puffin production data found that the relationship between ocean temperature and breeding success has shifted over time, with warming in recent decades increasingly linked to poor reproductive output.1Global Change Biology. Centennial relationships between ocean temperature and Atlantic puffin production reveal shifting decennial trends
In the North Pacific, the picture is more complicated but no less troubling. Studies of three puffin species across five sites found that different prey fish respond to ocean climate in opposite ways: sand lance availability rose with warmer conditions, while capelin became more available when temperatures dropped.2Fisheries Oceanography. Puffins reveal contrasting relationships between forage fish and ocean climate in the North Pacific That means warming doesn’t uniformly strip puffins of all food, but it does reshuffle the deck. Colonies that historically relied on capelin face steep declines as cold-water conditions become rarer, and even colonies where sand lance increases can struggle if other prey species vanish simultaneously or if the timing of fish availability falls out of sync with chick-rearing.
What Happens When the Wrong Fish Shows Up
It’s not just whether food is available but whether it’s the right food. Puffin chicks grow best on energy-rich fish like capelin and sandeels. When those species decline, adult puffins often switch to whatever is around, but substitutes can be nutritionally poor or the wrong size for a chick to swallow. In Newfoundland, researchers compared colonies where capelin was abundant with colonies where it was scarce. At capelin-poor sites, chicks received far less capelin by mass and instead ate more postlarval sandlance. Surprisingly, hatching success and fledging success were similar between sites in some years, and fledging weight was comparable at about sixty-eight to sixty-nine percent of adult mass.3Canadian Journal of Zoology. Atlantic Puffin (Fratercula arctica) chick diet and reproductive performance at colonies with high and low capelin (Mallotus villosus) abundance That finding suggests puffins can sometimes compensate by working harder or finding alternative prey of decent quality. But compensation has limits. In years when prey quality and quantity both crash, no amount of extra foraging effort can bridge the gap, and chick starvation follows.
This is a recurring pattern across seabird biology: adults can absorb moderate food shortages by flying farther and spending more energy, but their chicks pay the price when shortages turn severe. And in the worst years, adults themselves may skip breeding entirely, saving energy at the cost of producing no offspring.
Industrial Fishing and Competition for Prey
Puffins don’t just compete with changing oceans for their food. They compete with fishing fleets. In the North Sea, lesser sandeels are the target of an industrial fishery that converts the catch into fishmeal and fish oil rather than human food. Because sandeels also serve as the primary prey of puffins, guillemots, kittiwakes, and other seabirds, there has been longstanding concern that industrial fishing directly reduces the food available to breeding colonies.
When the sandeel fishery off eastern Scotland was closed in 2000, local sandeel abundance subsequently increased, and researchers tracked how seven seabird species responded over the surrounding years.4Canadian Journal of Fisheries and Aquatic Sciences. The impact of the sandeel fishery closure on seabird food consumption, distribution, and productivity in the northwestern North Sea The closure provided a natural experiment: remove the fishing pressure and see whether birds do better. The study examined sandeel consumption, at-sea distribution, and breeding success in relation to fish stocks. Results like these have informed ongoing debates about whether sandeel fishery closures should be expanded to protect seabird colonies more broadly, a conversation that remains politically contentious in countries where the fishery has economic value.
The tension here is real. Sandeel fisheries generate revenue, and fishery managers argue that total catches are a small fraction of the stock. Conservationists counter that fishing effort is concentrated in exactly the areas where seabird colonies forage, meaning localized depletion can devastate birds even if the overall stock looks healthy on paper. Some regions in the North Sea have adopted seasonal or area-based closures to protect key foraging grounds during the breeding season, but coverage is patchy.
Gillnet Bycatch
Beyond prey competition, fishing gear kills puffins directly. Gillnets, the mesh walls set in the water to catch fish, are invisible to diving birds. Puffins forage by swimming underwater, and when they dive into a gillnet, they become entangled and drown. This is called bycatch, and its effects can be devastating for small or declining populations.
Population modeling in the Kodiak Archipelago in Alaska illustrates how quickly bycatch can push puffin populations toward collapse. With zero bycatch mortality, tufted puffins in the region already faced a seven percent probability of local extirpation within fifty years, and horned puffins faced fourteen percent. Those baseline risks reflect other ongoing pressures. But adding even modest bycatch numbers dramatically worsened the outlook: for tufted puffins, removing just 100 birds per year from the population raised the fifty-year extirpation probability to thirty-three percent, and 200 birds per year pushed it to forty percent. Horned puffins were even more sensitive. Taking just 15 birds annually raised their extirpation risk to thirty-one percent, and 30 birds per year brought it to forty percent.5Biological Conservation. Gillnet bycatch increases risk of regional extirpation for tufted and horned puffins
Those numbers are striking because the annual bycatch figures involved are genuinely small. Losing 30 horned puffins a year to nets doesn’t sound catastrophic, yet for a slow-reproducing species that lays a single egg per year and doesn’t start breeding until age four or five, even small chronic losses compound over decades. This is one of the less visible threats to puffins because the birds that drown in nets are rarely counted or reported, especially in remote fisheries with limited observer coverage.
Plastic Pollution in the Ocean
Puffins swallow plastic. A study of stranded Atlantic puffins in southern Spain found that sixty-five percent of the birds examined had ingested plastics, averaging about two and a half items per bird, with one individual containing ten pieces.6Journal of Hazardous Materials. Characterisation of plastic debris (macro-, meso-, and microplastics) from stranded alcids in southern Spain Most of what the puffins swallowed was microplastic, with fibers being the most common shape. The dominant polymer was polyethylene, the material in plastic bags and packaging.
What plastic ingestion actually does to individual puffins is harder to pin down. The immediate risks include physical damage to the digestive tract, false feelings of fullness that reduce food intake, and chemical contamination from toxic additives leaching out of the plastic. For a bird that already faces food shortages, carrying a gut full of indigestible material that makes it feel less hungry is a dangerous combination. There’s also concern about bioaccumulation, where pollutants absorbed from plastics build up in body tissues over time, potentially affecting reproduction and immune function. The research on puffins specifically is still developing, but the ingestion rates are high enough to warrant concern, especially in populations already stressed by other factors.
Avian Influenza
The highly pathogenic avian influenza (HPAI) H5N1 outbreak that swept through wild bird populations starting in 2021 and 2022 added a new and frightening dimension to puffin conservation. Seabird colonies, where thousands of birds nest in close proximity, are ideal environments for respiratory viruses to spread quickly.
On the island of Newfoundland alone, surveys and citizen reports during the 2022 outbreak estimated roughly 13,500 seabird deaths attributable to HPAI. Northern gannets bore the heaviest toll with about 6,600 estimated deaths, followed by common murres at around 6,000. Atlantic puffins accounted for an estimated 282 deaths, and black-legged kittiwakes about 217.7Canadian Journal of Zoology. Geographic, ecological, and temporal patterns of seabird mortality during the 2022 HPAI H5N1 outbreak on the island of Newfoundland The puffin toll may sound modest compared to gannets and murres, but those numbers represent only what was found and reported in one region. Puffins nest in burrows, meaning sick or dead birds inside burrows are far less likely to be detected than species that nest on open cliff ledges. The actual mortality may be substantially higher than surveys captured.
What made this outbreak particularly alarming was its novelty. Wild seabird populations in the North Atlantic had not previously experienced HPAI at this scale. Unlike domestic poultry, where outbreaks can be managed through culling and biosecurity, there is essentially no way to intervene in a wild seabird colony once the virus arrives. If HPAI becomes a recurring seasonal threat rather than a one-off event, it could impose periodic mass mortality on populations that are already declining for other reasons.
Artificial Light and Stranded Fledglings
Young puffins, known as pufflings, leave their burrows for the first time at night, navigating toward the ocean by moonlight and starlight. Artificial light along coastlines disrupts this process. Fledglings are attracted to lights, which pulls them inland or onto roads instead of out to sea. Grounded pufflings are then vulnerable to predators, vehicles, and exhaustion.
This phenomenon has been documented anecdotally for years in places like Iceland’s Westman Islands, where residents run annual “puffling patrols” to collect stranded fledglings and carry them to the water. But experimental evidence confirming that light actually causes the strandings, rather than merely coinciding with them, is more recent. Researchers used controlled beach illumination experiments and maze tests to show that pufflings are genuinely attracted to artificial light. Significantly more fledglings stranded during lit conditions than during dark conditions, and in laboratory-style choice tests, pufflings consistently preferred light over darkness and somewhat preferred brighter light over dimmer light.8bioRxiv. Navigating the Night: Effects of Artificial Light on the Behaviour of Atlantic Puffin Fledglings
The practical implication is straightforward: coastal lighting near puffin colonies kills fledglings. Communities that reduce or shield artificial lights during the fledging season can directly reduce this mortality. It’s one of the few puffin threats where a local, low-cost intervention makes a measurable difference. Some Icelandic towns have already adopted light management during fledging, and rescue programs recover thousands of pufflings each year, though not every grounded bird is found in time.
Extreme Weather and Burrow Damage
Puffins nest in underground burrows, typically on grassy slopes or cliff tops on offshore islands. The burrow provides shelter from wind and some thermal buffering, but it’s also vulnerable to extreme weather. Heavy rainfall can flood burrows, drowning eggs or chicks, and saturated soil can cause burrow collapse, burying nests or forcing adults to abandon them. Research on burrowing seabirds has highlighted that extreme precipitation events are a factor that may be critical to investigate further, since flooding and collapse increase both breeding failure and the energy birds must spend on re-excavation.9FACETS. Burrow nests fall below critical temperatures of threatened seabirds but offer thermal refuge during extreme cold events
Climate projections suggest that extreme precipitation events will become more frequent and intense in many parts of the puffin’s range, particularly in the North Atlantic. Soil erosion on breeding islands, sometimes accelerated by overgrazing from introduced rabbits or other herbivores, compounds the problem by making slopes less stable. Some colonies have seen measurable losses of nesting habitat as cliff edges erode and turf thins. Unlike food availability, which fluctuates year to year, habitat degradation tends to be cumulative and slow to reverse.
Shrinking Genetic Diversity
A less visible but potentially consequential threat sits in the puffin genome itself. Genomic analysis of Atlantic puffins across their range, from Arctic colonies to temperate ones, has revealed a significant loss of genetic diversity over the twentieth century. As climate change shifts the distribution of suitable habitat and prey, populations that were once separated have come into contact and begun hybridizing, while isolated colonies have lost diversity through genetic drift.10Science Advances. Hybridization of Atlantic puffins in the Arctic coincides with 20th-century climate change
Why does genetic diversity matter for conservation? A genetically diverse population is better equipped to adapt to changing conditions because there is more raw variation for natural selection to work with. Populations that lose diversity become more vulnerable to disease, less able to cope with environmental shifts, and more prone to inbreeding depression, where harmful genetic variants accumulate because there aren’t enough different copies of genes circulating. For a species already hammered by food shortages, bycatch, disease, and pollution, reduced adaptive capacity is the kind of background vulnerability that makes every other threat worse. It doesn’t cause dramatic die-offs that make headlines, but it quietly narrows the margin for recovery.
Why Puffins Are Especially Vulnerable
Several features of puffin biology amplify the impact of these threats in ways that wouldn’t apply to a more prolific species. Puffins lay a single egg per breeding attempt, once per year. They don’t reach breeding age until around four or five years old. Adults can live into their thirties, which ordinarily compensates for the slow reproduction rate because each individual gets many chances to breed. But that life-history strategy only works when adult survival is high. When new sources of mortality appear, whether from bycatch, disease, or starvation, the population cannot bounce back quickly by producing larger clutches. Each lost adult represents years of future reproductive potential that vanishes.
Puffins are also colonial nesters, which concentrates risk. A single oil spill near a major colony, a disease outbreak at a dense nesting site, or a prey failure in the foraging range of one island can affect thousands of breeding pairs simultaneously. Colonial living has benefits, including shared vigilance against predators and social information about foraging, but it also means that catastrophic events hit a large fraction of the population at once rather than being spread out.
There’s also a detection problem. Puffins nest in burrows out of sight, forage far offshore, and spend most of the non-breeding season scattered across the open ocean. Population monitoring is difficult and expensive. Declines can proceed for years before anyone notices, and by the time colony counts confirm a downward trend, the underlying causes may have been operating for a decade or longer. Iceland’s largest colonies, for example, experienced years of poor breeding success before researchers fully grasped the scale of the decline.
How Different Puffin Species Compare
When most people picture a puffin, they’re thinking of the Atlantic puffin, the species found across the North Atlantic from Maine to Norway to Iceland. But there are three other species in the puffin family, and their situations differ. Tufted puffins, recognized by their dramatic golden head plumes, breed across the North Pacific from California to Alaska to Japan. Their populations have declined severely in the southern parts of their range, and the bycatch modeling from the Kodiak Archipelago shows how sensitive they are to even small additional mortality.5Biological Conservation. Gillnet bycatch increases risk of regional extirpation for tufted and horned puffins Horned puffins, also Pacific species, share many of the same threats. The rhinoceros auklet, a close relative sometimes included in puffin discussions, faces overlapping challenges with prey shifts in the North Pacific.
The threats vary in emphasis by region. Atlantic puffins in Iceland are most severely affected by sandeel declines tied to ocean warming. Atlantic puffins in the UK face a combination of prey depletion from industrial fishing and climate-driven changes in fish distribution. Pacific puffins contend more with bycatch in gillnet fisheries and with the dramatic ocean temperature fluctuations associated with marine heatwaves. Plastic pollution and avian influenza are relatively newer concerns that don’t yet respect these regional divisions. What all puffin species share is a vulnerability to disruption in the narrow band of small forage fish they depend on, combined with reproductive biology that gives them very little room to absorb extra losses.