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Microplastics Were Detected in 77% of Fecal Samples From Wintering Whooper Swans in North China

Wintering whooper swan in Beijing, China
Conservation · Threats

Microplastics were detected in 23 of 30 fecal samples from wintering whooper swans (Cygnus cygnus) at Swan Lake in Rongcheng, northern China. The study, first published online on 21 February 2026, compared plastics in swan feces with those found in surrounding water and sediment.

The overall detection rate in feces was about 77%, with a mean abundance of 0.4 microplastic items per gram. The researchers used the samples to examine how closely the plastics associated with the birds reflected contamination in their wintering habitat.

Fecal microplastics overlapped with those in the environment

Fragments were the most common form in both sediment and swan feces, with polypropylene and polyethylene among the dominant polymers. Fibres were more common in the water, where polyethylene terephthalate was prominent.

The composition of microplastics in fecal samples overlapped with the composition found in the surrounding water and sediment. The authors therefore suggest that whooper swans could be useful bioindicators for monitoring microplastic pollution at wintering sites.

Overall risk was low, but some higher-toxicity polymers were present

Three different pollution and ecological-risk indices all indicated that the overall indexed risk associated with the measured microplastic contamination was low. These indices combine features of the detected plastics; the study did not directly measure health effects in the swans. The study did, however, identify polymers with higher toxicity ratings, including polyacrylonitrile and polyurethane, in specific parts of the lake.

Source analyses linked much of the plastic contamination to local fishery operations, smaller runoff inputs and beach tourism. Different source types were associated with different shapes and polymer compositions.

Swan Lake is an important wintering area for migratory whooper swans and contains extensive seagrass habitat. The study does not show that the birds are currently experiencing high ecological risk from microplastics, but it demonstrates widespread exposure within the wintering environment and identifies local sources that could be targeted if pollution is to be reduced.

Sources and image credit

  1. Li, C., Liang, W., Yuan, Z., Zhu, L., Hou, X., & Dong, X. (2026). The occurrence and risks of microplastic pollutants to wintering Whooper Swans (Cygnus cygnus) in Swan Lake, North China. Environmental Research, 296, 124077. https://doi.org/10.1016/j.envres.2026.124077Primary peer-reviewed article first published online 21 February 2026. Microplastics occurred in 23 of 30 whooper swan fecal samples (76.67%), averaging 0.40 ± 0.40 items/g. Fecal composition overlapped with water and sediment; three indices indicated low overall ecological risk, although higher-toxicity polymers occurred locally.

Image: 星外之神 — wintering whooper swan (Cygnus cygnus) at Yuanmingyuan, Beijing, China, photographed 17 January 2026; representative wintering image, not a bird sampled at Swan Lake. Source: Wikimedia Commons. · CC BY-SA 4.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

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