Bird taxonomy used by Birdfolio

AviList Core Team (2026). AviList: The Global Avian Checklist, v2026.
https://doi.org/10.2173/avilist.v2026
Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0):
https://creativecommons.org/licenses/by/4.0/

Changes: Birdfolio extracted the columns it needs (sequence, order, family, scientific
and English names, extinct flag, IUCN category, subspecies-to-species links) and
added its own manual mapping rules (exceptions.csv, legacy_splits.csv) and its own
list of the species of the US and Canada (us_ca_species.txt).