Research shows that a seabird’s evolutionary family group predicts plastic ingestion better than its diet or hunting behavior. In a study of 93,281 seabirds from 240 species, 76% contained plastic, with pelicans showing 67% ingestion rates and penguins only 5%. According to Gram Research analysis, phylogenetic position was the strongest predictor of plastic risk, suggesting inherited traits matter more than lifestyle.
Researchers studied plastic ingestion in over 93,000 seabirds across 240 species to understand which birds are most at risk. According to Gram Research analysis, they found that three-quarters of seabird species contained plastic in their bodies. Surprisingly, what the birds ate and how they hunted didn’t predict plastic ingestion as much as scientists expected. Instead, the bird’s family tree, or evolutionary group, was the strongest predictor of plastic risk. Pelicans had the highest plastic rates while penguins had the lowest. This discovery could help scientists quickly identify which bird species need protection from ocean plastic pollution.
Key Statistics
A 2026 analysis of 93,281 seabirds across 240 species found that 76% contained plastic pollution, with ingestion rates varying dramatically by bird family from 67% in pelicans to 5% in penguins.
Research examining seabird plastic ingestion discovered that evolutionary family group predicted plastic accumulation better than diet, foraging method, body size, or ocean specialization, suggesting inherited traits drive plastic ingestion risk.
Among 240 seabird species studied, pelicans showed the highest plastic ingestion at 67% while penguins showed the lowest at 5%, demonstrating that phylogenetic position strongly influences plastic vulnerability.
The Quick Take
- What they studied: Which seabird species are most likely to swallow plastic pollution and what traits make them vulnerable
- Who participated: Data from 93,281 individual seabirds representing 240 different species collected from research studies worldwide
- Key finding: A bird’s evolutionary family group predicted plastic ingestion better than diet or hunting behavior. Seventy-six percent of seabird species contained plastic, with pelicans at 67% and penguins at only 5%
- What it means for you: Understanding which bird species are naturally more vulnerable to plastic helps conservation efforts focus resources where they’re needed most. However, this doesn’t mean some species are safe from plastic pollution, just that some are at higher risk
The Research Details
Scientists gathered information from existing research on plastic found in seabirds, creating a massive database of 93,281 birds from 240 species. They then analyzed this data to see if certain bird characteristics predicted which species would ingest plastic. The researchers tested whether a bird’s diet (what it eats), foraging method (how it hunts), how much time it spends in the ocean, body size, and evolutionary family group affected plastic ingestion rates.
To make sure their results were accurate, they accounted for differences in how studies were done. Some studies looked at more birds than others, some focused on specific age groups, and some used different methods to detect plastic. By adjusting for these differences, the researchers could fairly compare plastic ingestion across all 240 species.
The key innovation was using phylogenetic analysis, a method that maps how bird species are related through evolution. This allowed them to see whether plastic ingestion patterns followed family relationships rather than lifestyle choices.
This approach matters because it reveals something unexpected: a bird’s evolutionary history is more important than its behavior in determining plastic risk. This suggests that certain bird families may have physical features or instincts that make them more likely to mistake plastic for food. Understanding this helps scientists predict which species need urgent protection without waiting for new research on every single species.
This study’s strength comes from its enormous sample size of over 93,000 birds, making the patterns very reliable. The researchers carefully adjusted for differences in how studies were conducted, which strengthens their conclusions. However, the study relies on data collected by other researchers, so the quality depends partly on their methods. The researchers note that some species are understudied, meaning predictions for rare birds may be less certain. The study was published in Biology Letters, a peer-reviewed journal, meaning experts reviewed the work before publication.
What the Results Show
The analysis revealed that 182 of the 240 seabird species studied (76%) contained plastic in their bodies. This widespread problem shows that plastic pollution affects seabirds across many different families and lifestyles. When looking at specific bird groups, pelicans had the highest plastic ingestion rate at 67%, while penguins had the lowest at just 5%. These dramatic differences between bird families suggested that something about being a pelican or penguin affected plastic risk.
When researchers tested whether diet, hunting method, ocean specialization, or body size predicted plastic ingestion, they found these factors didn’t consistently explain the differences. A bird that hunted in a certain way or ate specific foods wasn’t reliably more likely to ingest plastic than other birds. Instead, phylogenetic position, the bird’s place on the evolutionary family tree, was the strongest predictor. This means that birds closely related to each other had similar plastic ingestion rates, even if they lived in different oceans or hunted differently.
The finding suggests that inherited traits, possibly related to how birds recognize food or their bill shape and size, may drive plastic ingestion more than behavior does. A pelican’s large pouch and feeding style may make it more likely to scoop up plastic along with fish, while a penguin’s diving and hunting method may naturally avoid plastic.
The study found that research design factors significantly affected results. The year a study was conducted, which ocean it studied, the bird’s age, and the sampling method all influenced whether plastic was detected. This means that older studies or studies using certain methods might have found more or less plastic than actually exists. The researchers accounted for these factors to get more accurate comparisons. The analysis also showed that sample size mattered: studies that examined more birds were more likely to find plastic, possibly because larger samples catch rare events.
Previous research suggested that a seabird’s diet and foraging behavior would be the main factors determining plastic ingestion risk. Scientists thought that birds eating small fish near the ocean surface would ingest more plastic than deep-diving birds. This study challenges that assumption by showing that evolutionary family group matters more. The findings align with recent understanding that plastic ingestion is a widespread problem across seabird species, but they add a new insight: which species are affected depends more on their evolutionary history than on how they hunt.
The study relies on data collected by other researchers using different methods, which can introduce inconsistencies. Some seabird species are well-studied while others are rarely examined, creating gaps in the dataset. The researchers couldn’t test all possible traits that might affect plastic ingestion, such as specific bill shape or diving depth. The study shows correlation between evolutionary family and plastic ingestion but cannot prove that evolutionary traits directly cause the difference. Future research with standardized methods across all species would provide clearer answers.
The Bottom Line
Use phylogenetic position as a rapid screening tool to identify seabird species at high risk for plastic ingestion. Focus conservation and monitoring efforts on bird families with historically high plastic ingestion rates, particularly pelicans and related species. Implement standardized plastic detection methods across all seabird species to fill knowledge gaps. Investigate specific morphological features of high-risk species to understand the mechanism behind plastic ingestion. These recommendations have moderate to high confidence based on the large sample size and careful statistical analysis.
Marine conservation organizations should use these findings to prioritize protection efforts for vulnerable seabird species. Researchers studying seabird health and ocean pollution should adopt standardized methods to improve future comparisons. Policymakers addressing ocean plastic pollution should recognize that different bird species face different levels of risk. Birdwatchers and citizen scientists can help by reporting plastic ingestion in seabirds they observe. People concerned about ocean health should understand that plastic pollution affects wildlife across many species, not just a few.
Immediate benefit comes from using this research to identify high-risk species for targeted monitoring and protection. Short-term benefits (1 to 2 years) would emerge from implementing standardized research methods across seabird studies. Medium-term benefits (3 to 5 years) would come from developing species-specific interventions based on understanding why certain families are vulnerable. Long-term benefits depend on reducing ocean plastic pollution overall, which requires broader environmental action.
Frequently Asked Questions
Which seabirds are most likely to eat plastic
Pelicans and related species show the highest plastic ingestion rates at 67%, while penguins show the lowest at 5%. A bird’s evolutionary family group predicts plastic risk better than its diet or hunting behavior, suggesting inherited traits make certain species more vulnerable.
Why do some seabirds ingest more plastic than others
Evolutionary family group is the strongest predictor of plastic ingestion. This suggests that inherited physical features, such as bill shape or feeding style, make certain bird families more likely to mistake plastic for food. Diet and hunting method alone don’t explain the differences.
How common is plastic in seabirds
Plastic is extremely common in seabirds. Seventy-six percent of the 240 seabird species studied contained plastic, affecting birds across nearly all major seabird families. This widespread problem shows ocean plastic pollution impacts seabirds globally.
Can scientists predict which bird species will ingest plastic
Yes, a bird’s position on the evolutionary family tree predicts plastic ingestion risk. Scientists can use phylogenetic relationships to quickly identify high-risk species without waiting for new research on each individual species, helping prioritize conservation efforts.
What can be done to protect seabirds from plastic
Focus conservation efforts on high-risk species like pelicans using phylogenetic predictions. Reduce ocean plastic pollution through better waste management and reduced single-use plastics. Support research using standardized methods to understand species-specific vulnerability factors and develop targeted protection strategies.
Want to Apply This Research?
- Track seabird sightings by species and note any visible plastic ingestion or entanglement. Record location, date, species, and observations in a standardized format to contribute to citizen science databases that help researchers monitor plastic pollution trends
- Use the app to learn which seabird species in your region are highest-risk for plastic ingestion. When you see these species, report sightings to conservation organizations and reduce your personal plastic use, especially single-use items that end up in oceans
- Set up recurring reminders to check for seabird research updates in your region. Track changes in plastic ingestion rates over time by comparing your observations to historical data. Share photos and observations through the app to contribute to long-term monitoring of seabird health and ocean plastic pollution
This research identifies patterns in plastic ingestion across seabird species but does not provide medical or veterinary advice. If you find an injured seabird, contact a local wildlife rehabilitation center. This study’s findings apply to wild seabird populations and should not be interpreted as guidance for captive birds. Consult with marine biologists or ornithologists for species-specific conservation decisions. The research relies on existing data with varying quality and methodology, so predictions for understudied species may be less reliable.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.