eBird — Global Bird Observations (Cornell Lab)

eBird is the largest biodiversity-related citizen-science platform on Earth measured by raw observation volume — run by the Cornell Lab of Ornithology since 2002. Unlike opportunistic platforms, eBird collects observations as structured **checklists with effort metadata** (duration, distance, protocol, observer count, all-species-reported flag), which makes it the gold standard for sampling-effort correction in citizen- science biodiversity analysis. Bulk access (the eBird Basic Dataset, EBD) is gated through a registration + custom-download form with usage terms that prohibit redistribution of raw EBD without permission.

Provider	Cornell Lab of Ornithology
Type	citizen
CNR score	60
Origin	https://ebird.org/
Provider URL	https://science.ebird.org/