AviList Updates – June 2026

Spruce Grouse Canachites canadensis was one of hundreds of species assessed by AviList in Phase I. At question was whether Franklin’s Grouse Canachites [canadensis] franklinii should be treated as a separate species or lumped with Spruce Grouse. Although there are differences in display behavior and minor plumage differences, there are also intermediates which led the Taxonomic Committee to retain them as the same species for v2025. Photo by Luke Seitz | Cornell Lab of Ornithology | Macaulay Library

11 June 2026 marks the one year anniversary of AviList: The Global Bird Checklist.

AviList was released on 11 June 2025 as a freely available consensus taxonomy for all birds of the world (AviList v2025). It will be updated annually (in September/October) and provides all key taxonomic and nomenclatural information.

Much has happened in the year since release, but most of it has been behind the scenes until recently.

The first priority for AviList was to move our systems, processes, and teams from Phase I to Phase II.

Phase I of AviList was the multi-year project to develop a collaborative approach to avian taxonomy that involved experts from the three major global checklists (IOC World Bird List, BirdLife International, and the eBird/Clements Checklist from the Cornell Lab of Ornithology), two regional checklists (AOS-NACC and SACC), and additional experts from around the world. Each discrepancy between these lists was identified, debated, and ultimately decided by the Taxonomic Committee (TaxCom). The final list of taxa in v2025 is the consensus list after all discrepancies (except those below the species level—subspecies will be a project for the upcoming phases) were resolved.

Phase II has required expanding the team substantially. Over the course of the past year, four Regional Advisory Groups (RAGs) have been added to the project. This has involved building out the teams and refining the process, both philosophically and technically, to assist the RAGs with identifying, debating, and recommending changes to the v2025 classification. Each RAG is tasked with reviewing existing information and/or new information, assessing it in an integrative taxonomic context, and providing a formal, written recommendation to TaxCom. For example, this proposal by the Tropical Asian RAG to split Cymbirhynchus affinis (Ayeyarwady Broadbill) from C. macrorhynchos (Black-and-red Broadbill) is just one of many such cases. Fortunately, for the Western Hemisphere, the long-established AOS-NACC and SACC are also affiliated and fill the role of RAGs for North America and South America, so those collaborations are also positive feedback loops with AviList. By early in 2026, the RAGs were fully formed, the plan was set, and ever since proposals have been prepared by the RAGs for assessment by TaxCom.

Recently, with fully operational RAGs, we have been able to provide two major improvements to the website that should greatly increase the transparency and utility of AviList and the AviList process as we work towards the next release in September/October 2026.

First, we now show Issues under consideration as a permanent link under our The Checklist menu. This page provides a tabular view to the proposals that have completed review by the RAGs and have been sent to TaxCom. The links to the actual proposals provide a look into the process and show the exact recommendations from the RAG (though the eventual TaxCom decision might differ). We hope this page helps users to understand what proposals are in progress and gives some insight into what to expect for v2026.

Second, we are thrilled to announce that we now provide an interactive Checklist Explorer. Instead of just the downloadable spreadsheet (which is the officially published version) from the Checklist page, this new interactive list has a lot of functionality that should make for an enhanced experience exploring the AviList taxonomy. It is easily searchable and filterable by rank, order, family, genus, and IUCN Red List category (IUCN code). While only certain core fields are shown as columns, expand the “Details” section (or click within a row) to see the full set of taxonomic information about a species, including the range, nomenclatural and bibliographic information, and more. Unique to this explorer is an option to set an alternate common name (e.g., UK English, French, German, Thai, Japanese, Zulu, or many more). These names come from eBird, which works with partners and volunteers to maintain over 115 regional versions of bird names in over 70 different languages and allows users to set those in eBird, Birds of the World, and Merlin. Note that many languages only translate a subset of names within a country or region (e.g., Kazakh has names for birds of Kazakhstan only) and only a handful provide a full global set of names; again see eBird’s common names page for details. This is one of the many benefits of taxonomic alignment that AviList has allowed, which facilitates the collaborative display of data resources like these names and the IUCN Red List codes.

Whatever results you display on the page itself can be exported as a CSV file right from the page and any filters you have applied will also apply in the CSV export; it is possible to download either the basic (7 core taxonomy columns plus IUCN status) or extended (all 26 columns, as in the official XLSX file). This new checklist explorer will be updated for all future checklist releases. Huge thanks to Adam Jackson who joined the team recently and helped to get this interactive Checklist Explorer built and released.

Finally, it is worth noting that the Checklist Explorer above actually uses a new minor revision of the AviList Checklist. While we released v2025 on 11 Jun 2025, the explorer uses a slightly revised version (v2025b). We have also replaced the v2025 spreadsheet and formally released v2025b as well. This version includes no changes to taxonomy or nomenclature of any taxa; these will be coming in v2026. Instead, this version primarily focuses on the grand alignment that the AviList team and partners are working towards. Since v2025 of AviList included key data fields from eBird/Clements and BirdLife International, this version only updates those fields as each group moves towards full alignment. So while v2025 included English Names, Species Codes, and Birds of the World links from alignment with v2024 of the eBird/Clements Checklist, this revision updates those fields to v2025 of eBird/Clements (with updated species codes and links to Birds of the World). Similarly, as BirdLife has revised from v9 to v10 of their checklist, this new version includes re-mapping of their v10 taxonomy to AviList v2025. This re-mapping for BirdLife is especially important since it involves revised IUCN Codes for all species, both from the 2025 Red List assessment and from the taxonomic changes. We should note that we did correct a few minor typos and other errors, but only those listed in our Errata as having been corrected.

TaxCom has been busy in 2026, and especially lately. There are many proposals from the Regional Advisory Groups, but one that was developed by the Palearctic RAG and then shared with AOS-NACC was a proposal to reconsider the genus of several Troglodytes wrens, that turn out not to be most closely related to other members of their group (see the phylogeny here). While one might have expected “The Wren” (Eurasian Wren Troglodytes troglodytes) to be the core member of the genus, the arcane nature of nomenclature means that in fact it was a North American wren that bears the type status for that genus and therefore the clade of little short-tailed wrens that were previously lumped as a single species now need to be placed in a new genus. The oldest available name is Nannus, so if accepted these could soon be known as Nannus troglodytes, Nannus hiemalis, and Nannus pacificus. Photo by Jay McGowan | Cornell Lab of Ornithology | Macaulay Library