Source and Citation Policy

Evidence hierarchy

Tier 1 includes government and public-health agencies, university extension programs, peer-reviewed research, recognized taxonomic databases, conservation-status databases, and environmental or pesticide regulators.

Tier 2 includes major natural-history museums, accredited zoos and aquariums, established scientific institutions, professional associations, and conservation organizations with documented methods.

Tier 3 commercial or journalistic sources may provide limited context. They do not stand alone for identification, health, chemical, legal, or safety claims.

Wikipedia may help locate original references but should not be the only source of record.

Minimum standard for rebuilt articles

An ordinary article should use at least two independent sources, normally including a primary, official, scientific, or institutional source. Major factual claims should be cited near enough for readers to understand what the citation supports.

Health, pesticide, disease, venom, invasive-species law, and emergency guidance require direct official or peer-reviewed evidence and the appropriate qualified review.

Verification and conflicts

An editor must open each source and check that it supports the claim and geography. Broken, circular, irrelevant, or machine-invented citations are rejected. Material disagreements and uncertainty should be explained, not hidden.

Report a weak or broken citation through corrections.