A 16-year study from Lord Howe Island found record levels of plastic ingestion in fledgling sable shearwaters.
In 2025, one bird was found with 894 pieces of plastic weighing 64.21g, while another in 2026 contained 644 pieces weighing 67.4g.
Researchers said plastic ingestion remained common across the population, but the number and mass of plastic pieces found in individual birds have risen sharply in recent years.
The study says adult birds struggling to find enough prey may be mistaking floating plastic debris for food and feeding it to their chicks.
Australian seabirds are being found with record amounts of plastic in their stomachs, with plastic ingestion rising sharply in recent years, a 16-year study has found.
Scientists analysing records from Lord Howe Island, about 650 kilometres off Australia’s east coast in the Tasman Sea, found a steep increase in both the number and mass of plastic pieces swallowed by fledgling sable shearwaters (Ardenna carneipes). In one case, a single bird was found to have ingested 894 pieces of plastic.
Lord Howe Island hosts the world’s largest known population of sable shearwaters, with an estimated 22,000 breeding pairs, according to the study.
The findings, published in the journal Earth’s Future, analysed plastic ingestion data collected between 2010 and 2026. Researchers found that the prevalence of plastic ingestion in the population remained broadly consistent, typically between 75 per cent and 85 per cent. But the number and mass of plastic consumed by individual birds rose rapidly, particularly in the final five years of the study.
In 2025, one bird was found to have swallowed 894 pieces of plastic weighing 64.21 g. In 2026, another contained 644 pieces weighing 67.4 g.
The authors said data from 2012 had once been considered the worst-case scenario. That year, one bird was found with 276 plastic items weighing 64.1g, a record that stood for nearly a decade.
At the time, researchers thought sable shearwater fledglings could not physically contain more plastic, or survive being fed less food and more plastic.
“We were wrong,” the authors wrote. The record for the most plastic ingested by a single chick has been broken several times in recent years, they said.
The study shows how rapidly the plastic burden has increased. A bird examined in 2011 had set an earlier record with 276 pieces weighing 64.1 g. That was exceeded in 2023, when one fledgling contained 403 pieces weighing 52.53 g.
The record was broken again in 2024, when a bird contained 407 pieces weighing 26.30 g. It nearly doubled in 2025, when 894 pieces were found in one bird, and remained extremely high in 2026, when another bird contained 644 pieces.
Researchers estimated that the 2025 burden would amount to roughly 30 pieces of plastic in each food load delivered to the chick, assuming the plastic was being fed at a constant rate along with food.
Looking at the underlying ecological reasons, the study said adult shearwaters may be struggling to find enough fish prey. This could be contributing to a long-term decline in chick body condition, with fledglings now weighing about 25 per cent less than they did a decade ago.
Starving adult birds may also show reduced prey selectivity, misidentifying floating plastic debris as food and feeding it to their chicks during foraging trips across the Tasman Sea.
The plastic does not necessarily come from Lord Howe Island itself, the study clarified. During the breeding season, the birds forage across the Tasman Sea and move north towards Brisbane and south towards the Bass Strait. A typical foraging trip during chick-rearing lasts between three and 11 days.
The study said the suffering experienced by affected birds is visible in widespread scarring of the stomach and organs, severely stunted wings, emaciated bodies and disrupted brain development.
“As plastic-related pressures on sable shearwaters increase, the species’ ability to cope with other, cumulative pressures is eroded,” the authors said. They said rapidly changing systems require careful consideration of the most relevant analyses and metrics, which may differ from those used historically.
Among the plastic items identified, bottle lids and resin pellets broadly reflected overall plastic exposure. A large number of lids and pellets was recorded in 2012, followed by a general increase over time and a notable rise between 2024 and 2026.
The number of pellets ingested by birds in 2014 was unexpectedly high, with an average of 4.2 pellets, especially given the low mass and total number of plastic items recorded that year. In 2012, lids and pellets each accounted for about 4 per cent of ingested items. By 2025, lids and pellets together exceeded 5.7 per cent of total items consumed by birds, showing an increase in bottle caps and nurdles, or industrial resin pellets.
The authors said the scale of policy action must outpace environmental decline. “As a society, it is imperative that the scale of our response to crises, including policy measures, exceeds the pace of environmental deterioration,” they wrote. “For plastic pollution, a bold, legally enforceable Global Plastics Treaty and dedicated, sustained funding stream are urgently required.”