Gram Research analysis of a 2026 study found that 28 of 31 Yelkouan shearwaters, a seabird from the Mediterranean, had swallowed plastic litter. Researchers also detected phthalate chemicals in the birds’ tissues. The study suggests plastic is an added stressor for this species, but it could not determine whether the chemicals came from plastic, food, or the environment.
Gram Research analysis of a 2026 study looked at 31 Yelkouan shearwaters, a seabird found along Italy’s Tyrrhenian coast, to see how much plastic they swallow and whether chemicals from plastic build up in their bodies. Plastic was found in 28 of the 31 birds, or 90.3%, with an average of about 20 pieces per bird. Most of these pieces were tiny microplastics, and most of those were found in the gizzard, the muscular stomach section where food is ground up. Researchers also detected several phthalates, chemicals used to make plastic soft and flexible, in the birds’ tissues. The study did not show whether the chemicals came from swallowed plastic, food, or the environment. The authors say the findings add to the pressures this threatened species already faces, such as fishing bycatch, light pollution, and predators that were introduced by people.
Key Statistics
A 2026 study of 31 stranded Yelkouan shearwaters found plastic litter in 28 of the birds, or 90.3%, with an average of about 20 pieces per bird.
In a 2026 study of Yelkouan shearwaters from Italy’s Tyrrhenian coast, 94.9% of the microplastics found were located in the gizzard.
A 2026 study of 31 Yelkouan shearwaters found DBP, a phthalate chemical used to soften plastic, in every bird tested.
The Quick Take
- What they studied: Scientists wanted to know whether seabirds called Yelkouan shearwaters are swallowing plastic litter and whether chemicals from that plastic end up in their bodies.
- Who participated: The study examined 31 Yelkouan shearwaters that were found stranded, meaning they were washed up or found on land, along the Tyrrhenian coast of Italy. Researchers examined the birds’ stomachs and tested tissue samples from their kidneys, liver, muscle, and a fatty gland near the tail.
- Key finding: Plastic litter was found in 28 of the 31 birds (90.3%), averaging about 20 pieces per bird. Most of it was microplastics, and five types of phthalate chemicals were detected in the tissues, with DBP found in every bird tested. The chemical levels did not clearly match how much plastic a bird had swallowed.
- What it means for you: This study is about seabirds, not people, so it does not tell you what to eat or how to change your diet. It does show that plastic pollution reaches wildlife at large scale, which is one reason many people choose to reduce single-use plastic, especially for food and drinks.
The Research Details
The researchers studied birds that had been found stranded along the coast, so they did not choose birds at random from the wild. After each bird was examined, the team opened its digestive tract and sorted out every piece of litter they found. They confirmed that the items were plastic using a lab method called FTIR spectroscopy, which identifies materials by how they absorb infrared light.
The team also tested tissue samples from four parts of each bird’s body. They checked for 11 types of phthalates, chemicals that are commonly used in plastics and can be released over time. Laboratory instruments measured how much of each chemical was present in each tissue type.
By combining the stomach findings with the chemical tests, the researchers were able to compare what the birds swallowed with what showed up in their bodies. This type of combined approach can reveal links that a single test would miss, although it cannot prove what caused those links.
Looking at both the swallowed plastic and the chemicals inside the body gives a fuller picture than either measurement alone. Plastic pieces show direct exposure, while tissue tests show whether chemicals were absorbed and where they collected. Because the birds were found stranded, the results describe a group of birds that were already in trouble, which the authors take into account when interpreting the findings.
The study was published in Environmental Pollution, a peer-reviewed scientific journal. Its methods were clearly described, and the team used established lab techniques to identify plastic and measure chemicals. However, the sample of 31 birds is small, and all were collected from one region, so the results may not apply to every shearwater colony. Readers should treat it as an important early look at the problem rather than a final answer.
What the Results Show
Plastic was found in 28 of the 31 birds, which is 90.3% of the group. In total, researchers recovered 569 plastic items weighing 685.8 milligrams. On average, each bird had about 20.3 items, with an average weight of about 24.5 milligrams. The researchers say these amounts are higher than the levels previously considered safe thresholds for shearwaters, although the spread between birds was very wide.
Microplastics made up 77.9% of the items. These are plastic pieces smaller than 5 millimeters, and they were mostly fragments and thin films made of polyethylene and polypropylene, the same plastics used in bags, bottles, and food wrap. Of the microplastics, 94.9% were found in the gizzard, where the bird grinds up its food.
Five of the 11 phthalates tested were found at levels above the detection limit: DEP, DIBP, DBP, DEHP, and DNOP. DBP was measured in every bird. Total phthalate levels differed between body tissues, and the highest levels were found in the uropygial gland, a small oil-producing gland near the tail that birds use to keep their feathers waterproof.
The amount of plastic a bird had swallowed did not match up with the amount of phthalates in its tissues. This means the researchers could not tell whether the chemicals came from the plastic the birds ate, from their food, or from the surrounding environment.
The researchers noted that the tissue results varied by organ, which suggests that different body parts absorb or store these chemicals in different ways. Because phthalates are widely used in everyday products, they are found throughout many environments, which makes it hard to trace a single source. The finding that the uropygial gland had the highest levels is especially interesting because this gland is involved in feather care, and any chemical that collects there could affect feather health, though the study did not test this directly.
Earlier research has shown that many seabirds worldwide swallow plastic, and that plastic particles and chemicals can move from the digestive tract into other tissues. This study adds evidence from the Mediterranean, a region that has had less research on this topic. It also supports concerns that Yelkouan shearwaters face several threats at once, which makes additional pressures like plastic more worrying for a species already in decline.
The most important limitation is that the birds were stranded, so they may have been sicker or weaker than healthy birds at sea, and this could affect the results. The sample of 31 birds is small and comes from one region, so the findings may not represent all shearwater populations. The study also could not determine where the phthalates came from, because they can enter the body through food, water, air, or swallowed plastic. Finally, this is a single snapshot in time, so it cannot show how exposure changes across seasons or years.
The Bottom Line
Research shows that Yelkouan shearwaters in this region commonly swallow plastic, and the authors recommend long-term monitoring of plastic ingestion and chemical contamination (high confidence that plastic ingestion is occurring). Whether plastic-linked chemicals are causing harm to these birds remains uncertain and needs more study (low to moderate confidence). For people, the study points toward reducing plastic waste in general, but it does not establish a direct health risk to humans from this evidence.
Conservation groups, wildlife managers, marine researchers, and policymakers in the Mediterranean should pay close attention, since the study highlights the Tyrrhenian Sea as a key breeding area. People interested in ocean health and reducing plastic waste will also find the results useful. Readers looking for personal dietary advice should not apply these findings directly, because the study was about birds rather than humans.
Changes in plastic pollution usually take years to show measurable results in wildlife populations. Monitoring studies like this one generally need to be repeated over several seasons or years before scientists can tell whether plastic and chemical levels are rising, falling, or staying stable.
Frequently Asked Questions
How much plastic do seabirds like Yelkouan shearwaters swallow?
In a 2026 study of 31 stranded Yelkouan shearwaters, researchers found plastic in 28 birds. The average bird had about 20 plastic items, and microplastics made up 77.9% of all items recovered from the group.
Do chemicals from plastic end up in seabird bodies?
Research shows that phthalate chemicals used to soften plastic were detected in the tissues of Yelkouan shearwaters. The highest levels were in the uropygial gland near the tail, while DBP was found in every bird tested in the 2026 study.
Does eating plastic make seabirds sick?
The 2026 study did not directly measure illness or health harm. It found that plastic is an added stressor for Yelkouan shearwaters, which already face threats such as bycatch, light pollution, and introduced predators.
Should I change my diet because of plastic found in seabirds?
This research studied seabirds, not people, so it does not provide dietary guidance. Reducing single-use plastic food packaging and avoiding microwaving food in plastic containers are practical steps many people take to limit plastic exposure.
Want to Apply This Research?
- Track the number of single-use plastic food containers, bottles, or wrappers you use each week, and set a simple goal such as reducing that count by 20% over one month. You can also log how often you choose reusable containers or glass storage for leftovers.
- Use glass or stainless steel containers for storing and reheating food, and avoid microwaving food in plastic containers, since heat can increase the release of chemicals from plastic. Choose whole foods with minimal packaging when possible, and keep a reusable bag and water bottle with you.
- Review your weekly log every month to look for patterns, such as which meals or shopping trips produce the most plastic packaging. Over several months, you can compare your totals to your starting baseline and celebrate steady reductions. Because this research is about wildlife rather than personal health, treat this tracking as a way to reduce waste rather than a measure of health risk.
This article summarizes a study of Yelkouan shearwaters, a wild seabird species, and its findings apply to wildlife rather than to human health. The research did not test for disease or health outcomes in people and cannot be used to diagnose or treat any condition. Anyone with concerns about chemical exposure or diet should speak with a qualified healthcare professional. This summary is for general education and is not medical or nutritional advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.