The potential of aerial insectivores for monitoring microplastics in terrestrial environments
Bibliographic record
Abstract
Limited research has been conducted on microplastics in terrestrial ecosystems and biota, despite being some of the most ubiquitous environmental pollutants. We investigated the presence of microplastics (over 125 μm) in tree swallow (Tachicyneta bicolor) chicks (10 d. o.), an aerial insectivore whose diet involves terrestrial and/or freshwater sources. Swallows nested immediately downstream (300 m) of the discharge pipe of a large, urban wastewater treatment plant (WWTP) or at a rural conservation area (40 km apart). Anthropogenic microparticles (including microplastics) were identified in nearly all WWTP chicks (90%; N = 20) and reference chicks (83%; N = 20). All microparticles were fibers (100%) in the gastro-intestinal (GI) tracts of WWTP nestlings, whereas unexpectedly, they were more diverse in the GI tracts of reference chicks, with ~15% characterized as pre-production plastic pellets. The fecal sacs of most nestlings (90%) contained microparticles, and all were characterized as fibers suggesting their excretion by tree swallows. Compared to WWTP chicks, the reference chicks had more microparticles in their fecal sacs and larger particles (length, width) in their GI tracts, likely reflecting the more aquatic-based diet of the reference chicks fed insects caught adjacent to the nearby dam, compared to the more terrestrial-based diet of the WWTP chicks. The numbers of microparticles were not correlated between GI tracts and fecal sacs, nor with the chicks' condition or size (weight, organs, feathers). We recommend sampling macroinvertebrate prey to permit stronger conclusions regarding WWTPs as possible sources of microplastics for swallows, and to determine if such macroinvertebrates may be a non-lethal method to characterize microparticle diversity ingested by birds as presently identified in chicks' GI tracts. We conclude that sampling fecal sacs only, while not indicative of the diversity of microplastics ingested by terrestrial passerines (e.g., tree swallows), is useful for determining their exposure to microparticles.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".