Claim

In a seven-year biomonitoring study of 1,003 Barred Owls in northwestern California, second-generation anticoagulant exposure among young owls fell from about 50% in 2019 to about 20% in 2024, while vitamin D3 rodenticide was detected in 18.5% overall and all rodenticides in up to 46%.

Type QUANTITATIVE · truth-evaluable: yes · status at snapshot: ACTIVE · created seq 19748

45 words; atomic claims are usually under 25a conjunction joins clauses that may be separately evaluablea comma-separated series may list several propositions

Referenced 107 times: checked 2, looked up by assistants 0, viewed 73, shared 32. A count of attention, not evidence.

Topics

Wildlife · 1efd24fe Public health · 1efd24fe

Assessment

Supported

Score: 0.8085 under ledger-default@0.3.0 at snapshot 27745

3 of 4 review checks done · 1 counted · 2 by the author only

3 independent evidence lineages · review checks 1 of 4 · stability MEDIUM

Main unresolved issue: 4 counted evidence items have no independence review; repeats of one origin may be counted as several coverage:6647c83b-e8ab-8154-87a2-12e08b5c9718

Not yet independently audited.Evidence points both ways.Evidence reviewed so far supports this claim, but only 1 of 4 review checks has been done.A quoted passage from journals.plos.org was not found on the page when Galedra fetched it.

Why?

Strongest counted support: The report directly states the 1,003-owl sample, exposure decline, vitamin D3 detection rate, and all-rodenticide prevalence. weight 1.800000 evidence

Strongest counted contradiction: An independent subadult-focused sample reports 36% second-generation anticoagulant exposure and persistence five years after the California ban, indicating ongoing contamination despite restrictions. weight 0.540000 evidence

Suppressed as dependent: The passage directly reports the 1,003-owl dataset, temporal anticoagulant exposure decline, vitamin D3 detection, and overall rodenticide prevalence.

Review gaps: qualifiers reviewed, opposing search done, independence reviewed

What would most change this: One independent, direct measurement that contradicts this claim would move it from Supported to Leans contradicted.

Hide calculation

0.8085 under ledger-default@0.3.0 at snapshot 27745 · state Supported · Review checks: 1 of 4 · stability MEDIUM · 4 sources, 3 independent lineages

Model ledger-default@0.3.0 (the default model, not the answer) · snapshot 27745 · trace sha256:c7df2fd2d58964d7dee8d1e984934ee0c572cb002116c79b09ec01f3adac33fc

Last changed at entry seq 25876; nothing logged since has borne on this claim.

How the number was reached

Each counted link is weighed by multiplying the factors the model declares; a factor it does not declare is not shown. Every factor name below links to what that number means.

Link	Working	Weight	Counted as
c1433048 contradict	relevance MODERATE 0.6 × observation DIRECT_TEXT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	0.540000	0.540000
99321222 support	relevance DIRECT 2.0 × observation DIRECT_TEXT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	1.800000	0.000000 (dependent strongest only, kept fd8a67ea)
fd8a67ea support	relevance DIRECT 2.0 × observation DATASET_RESULT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	1.800000	1.800000
04a0d4d2 support	relevance WEAK 0.2 × observation DIRECT_TEXT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	0.180000	0.180000

prior 0.50 → log-odds 0.000000 + 1.440000 (the counted weights) = 1.440000 → probability 0.8085

Under neighbouring settings of the same model: 0.7326 to 0.8667, a spread of 0.1341.

Half-even rounding, six places for weights and four for the probability. The same inputs under the same model reproduce this exactly; that is what the trace hash above is for. How a score is worked out explains every factor, why it is there, and what the model sets it to.

Your view

Registered views

Nobody has registered a view yet.

Registered views are personal belief, not evidence: they never change Galedra's assessment. Affiliations are self-declared and shown only for groups of 5 or more.

Checked as part of

Statements this claim was broken out of. The claim is scored on its own; a statement's reading only counts its claims.

“In a seven-year biomonitoring study of 1,003 Barred Owls in northwestern California, second-generation anticoagulant exposure among young owls fell from...” · 1 claim · 29 September 2026
“In a seven-year biomonitoring study of 1,003 Barred Owls in northwestern California, second-generation anticoagulant exposure among young owls fell from...” · 1 claim · 29 September 2026

Evidence for

The report directly states the 1,003-owl sample, exposure decline, vitamin D3 detection rate, and all-rodenticide prevalence.

From Largest-ever study of its kind shows California’s rodenticide restrictions are working, and flags new rodenticides rising in their place Read 2026-09-29 Relevance DIRECT Steps 0 Counted
The passage directly reports the 1,003-owl dataset, temporal anticoagulant exposure decline, vitamin D3 detection, and overall rodenticide prevalence.

From Largest-ever study of its kind shows California’s rodenticide restrictions are working, and flags new rodenticides rising in their place Read 2026-09-29 Relevance DIRECT Steps 0 Counted
An earlier independent California wildlife study found widespread second-generation rodenticide exposure in fishers, providing contextual support for the new owl study's finding that forest-food-web contamination is widespread, while involving a different species and period.

From Anticoagulant Rodenticides on our Public and Community Lands: Spatial Distribution of Exposure and Poisoning of a Rare Forest Carnivore Read 2026-09-29 Relevance WEAK Steps 0 Counted

Contextual corroboration only; this earlier fisher study does not reproduce the owl exposure trends or vitamin D3 prevalence.

Evidence against

An independent subadult-focused sample reports 36% second-generation anticoagulant exposure and persistence five years after the California ban, indicating ongoing contamination despite restrictions.

From Using fine-scale aging in Barred Owls to understand timeline of rodenticide exposure in northwestern California Read 2026-09-29 Relevance MODERATE Steps 0 Counted

Independent context challenges any broad interpretation that regulatory restrictions eliminated or uniformly reduced second-generation anticoagulant exposure.

Qualifications

None.

Suppressed as dependent

Evidence	Group	Kept instead
3c6a5c57		fd8a67ea

Inferences

Concluded from

None.

Used as a premise in

None.

An inference is interpretation, not evidence: it never changes the assessment of its conclusion. Each premise is a claim with its own evidence.

Threads

None. Threads are for disagreements about how a determination was made — a statement whose figures are not in the passage it rests on, two sources that may share an origin. Something about the world belongs in the evidence above.

Claim edges

None. Edges are stored and displayed; v0.1 does not propagate probability across them.

Review checklist

Review checks: 1 of 4

3 checks by this claim's own author, alongside the independent review above. 1 OPPOSING EVIDENCE SEARCH · 1 QUALIFIER CHECK · 1 EVIDENCE VERIFICATION. A check by the person who recorded a claim does not raise its review coverage.

Check	Done	By
qualifiers reviewed	no
opposing search done	no
independence reviewed	no
primary source reviewed	yes	04a0d4d2

Summary

Supported. The main support is: The report directly states the 1,003-owl sample, exposure decline, vitamin D3 detection rate, and all-rodenticide prevalence. fd842fb8

Against that, contradiction: An independent subadult-focused sample reports 36% second-generation anticoagulant exposure and persistence five years after the California ban, indicating ongoing contamination despite restrictions. 5ce87b38

1 further item repeats the same origin and is not independent evidence. 3c6a5c57

A search for evidence in the opposing direction found something; see the counted evidence. fb267410

Review checks: 1 of 4. coverage:6647c83b-e8ab-8154-87a2-12e08b5c9718

Generated by stub-v0.1; every sentence cites graph ids.

Contribution history

seq	event	detail
19748	APPENDED
19749	ACCEPT	AUTOMATIC_AFTER_VALIDATION
19754	LINK_EVIDENCE	by 1efd24fe (accepted)
19756	TASK_RESULT	by 1efd24fe (accepted)
19766	LINK_EVIDENCE	by 1efd24fe (accepted)
25875	TASK_RESULT	by 1efd24fe (accepted)

Score trace

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  "code_hash": "sha256:c61a6fdf35a754a0d7e958df149036a083c0eaeb7d2d2e52704ec32b0c36def7",
  "contested": true,
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  "config_hash": "sha256:86768038080b8ab5233f1e4b7aba10af05b5bb44caa432095150b90e81209809",
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