The most recent checklist has been updated to follow the taxonomic order of bird species set forth by the American Ornithological Society (AOS). This last supplement contains no spit or lump that pertains to Wisconsin species. The only addition to the checklist was a bird classified as a hypothetical species. The Plumbeous Vireo was observed by only one person and they obtained no photographic evidence. The state total of valid species remains at 441 with 12 hypothetical species.
Decisions regarding the inclusion of species on this list are made by the WSO Records Committee. Contact firstname.lastname@example.org for more information.
The checklist is available as a PDF file or an Excel Spreadsheet:
Last updated March 16, 2021.