Tracing the origin of migratory pests using geochemical fingerprinting : application to European starling in the Okanagan Valley of British Columbia, Canada
Bibliographic record
Abstract
The European starling (EUST) (Sturnidae: Sturnus vulgaris L.) is an invasive bird in North America where it is an agricultural pest. In British Columbia (Canada), the EUST population increases in orchards and vineyards in autumn, coinciding with ripening fruits. Starlings also create damage in dairy farms and feedlots by eating and contaminating food, and spreading diseases. Damage can be partly mitigated by the use of scare deterrents. However, scare techniques mainly serve to divert flocks until they become acclimated. Large-scale trapping and euthanizing before they move to fields and farms is the most practical means of preventing damage, but requires knowledge of natal origin. Within a small (20,831 km²), agriculturally significant portion of south-central British Columbia, the Okanagan Valley, I employed analyses of 21 trace elements in bone tissue to discriminate the spatial distribution of juvenile EUST and to reveal the geographic origin of the problem birds. Stepwise discriminant analysis of trace elements classified juveniles from 64-79 % accurately to their natal origin, including sites that are 12 km apart. The elemental fingerprint of juveniles collected in the same area was different in two consecutive years (2015 and 2016). In both years, the majority of problem birds (55% in 2015 and 79 % in 2016) caught in vineyards and orchards were derived from the North Okanagan. In contrast, 89% of problem birds caught at dairy farms and feedlots were not from Okanagan and 11% were local in 2015; 100% of problem birds were local in 2016. It is unlikely that starlings from outside the region were misidentified as Okanagan Valley starlings because the geochemical fingerprints of those outside of the valley are very distinct. Thus, elemental signatures can separate populations with a high degree of spatial accuracy within several 10s of km, yielding a promising tool for identifying the geographic origin of migratory birds even over small geographic scales. These findings suggested that further control of starlings in vineyards and orchards, be targeted to the northern and southern regions of the valley; control in dairy farms and feedlots will require an expansion of the trapping program outside the region.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".