ECOREGISTROS JOINS AVILIST, THE NEW UNIFIED GLOBAL TAXONOMIC SOURCE

In the world of birdwatching and citizen science, taxonomy—that is, the system that classifies and organizes species—has historically posed challenges. There are multiple internationally recognized taxonomic sources, including the Clements Checklist (currently used by eBird), the IOC World Bird List, and the HBW & BirdLife International Taxonomic Checklist, the latter of which has been adopted by EcoRegistros for many years.

A bold new project called AviList has been recently launched, aiming to unify all these taxonomic sources into a single global list. The magnitude of this effort is such that it has gained the direct support of key institutions like the Cornell Lab of Ornithology and BirdLife International. These are now among the main members of the working group responsible for producing the unified list. All signs point to AviList becoming the new global standard for bird classification, and major systems are expected to adopt this taxonomic source.

Until now, EcoRegistros, a citizen science platform dedicated to biodiversity recording and conservation, used version 9.0 (2024) of the HBW & BirdLife International checklist, with which it has always maintained an affinity. However, the current context presents new challenges: with the increasing ease of exporting and importing data between different platforms, many users actively participate in multiple systems simultaneously. The difference in taxonomies among the various platforms is one of the main sources of conflict, causing errors, lockouts, and even data loss, in addition to a huge investment in the time management of these issues. For this reason, EcoRegistros has decided to officially join AviList.

Adopting AviList means that EcoRegistros will have a taxonomy that is almost identical to the most important global platforms, and a more agile and direct updating process. Instead of waiting for BirdLife to implement the changes derived from AviList and then incorporate them, the new scheme will allow direct synchronization of taxonomic updates from the base source, gaining precision and speed. It is worth noting that this decision does not imply the loss of existing references. Species profiles in EcoRegistros will continue to include conservation status and direct links to the official descriptions from BirdLife International, which is essential information for researchers, conservationists, and birdwatchers.

With this decision, EcoRegistros reaffirms its commitment to data quality and organization, interoperability between systems, and continuous improvement in favor of an increasingly integrated, modern, and global citizen science. And finally, most platforms will be working on the same taxonomic basis, maximizing compatibility.

The latest taxonomic update in the EcoRegistros database, that is, switching from BirdLife International taxonomy to AviList, brings a true reconfiguration. Hundreds of new species were added, many others ceased to be considered valid, and many more changed their genus or specific epithet. In addition, modifications were recorded in the family classification of numerous species.

In parallel, all English names were updated according to a standardized list. In contrast, for Spanish names, the decision was made to respect cultural and regional diversity, avoiding the imposition of a single list. That is why, in EcoRegistros species profiles, each species has a main name and several secondary names, which are also valid for searches and submitting records.

In the case of Argentina, although the total number of species changed little, many scientific names were updated. The changes in species names and counts are mostly due to processes known as splits (splitting one species into two or more) and mergers (merging several species into one), although other factors also play a role.

A new species for Argentina

Among the updates in AviList, a new species is officially included: the Eastern Rockhopper Penguin (Eudyptes filholi), a species that inhabits New Zealand and was previously considered a subspecies of the Southern Rockhopper Penguin (Eudyptes chrysocome). Since this taxon, formerly a subspecies, has records in Argentina, it is now added as a new species to the country’s avifauna. The inclusion is based on records from the Bahía de San Antonio Protected Natural Area, in Río Negro, and published in 2019 in Nótulas Faunísticas by Mariano Costa and Helena Amira Mandado. That publication documented, for the first time, the presence of this species in continental Argentina, specifically in Las Grutas, Río Negro.

AviList (2025) recognizes it as a species based on genetic studies, although it notes that a detailed analysis of its vocalizations is still lacking, which could lead to future revisions. In the meantime, we welcome the Eastern Rockhopper Penguin (Eudyptes filholi) to the list of Argentine birds and EcoRegistros!

Changes in already known species

Species mergers, where two or more previously separate species are now considered a single species with different subspecies, are also registered. In many cases, only one of these subspecies occurs in Argentina, so for local observers, the change is essentially just a modification of the scientific name. However, in some specific cases where both merged species are present in the country, the effective number of recognized species is indeed reduced.

The details of the changes are the following:

1) Lugensa brevirostris to Aphrodroma brevirostris.
2) Bubulcus ibis to Ardea ibis.
3) Ixobrychus involucris to Botaurus involucris.
4) Ixobrychus exilis to Botaurus exilis.
5) Oxyura ferruginea to Oxyura jamaicensis.
6) Accipiter bicolor to Astur bicolor.
7) Accipiter superciliosus to Microspizias superciliosus.
8) Accipiter chilensis to Astur chilensis.
9) Laterallus leucopyrrhus to Rufirallus leucopyrrhus.
10) Neocrex erythrops to Mustelirallus erythrops.
11) Porphyrio martinicus to Porphyrio martinica.
12) Laterallus spilopterus to Laterallus spiloptera.
13) Porzana albicollis to Mustelirallus albicollis.
14) Coturnicops notatus to Laterallus notatus.
15) Micropygia schomburgkii to Rufirallus schomburgkii.
16) Larus maculipennis to Chroicocephalus maculipennis.
17) Larus cirrocephalus to Chroicocephalus cirrocephalus.
18) Larus scoresbii to Leucophaeus scoresbii.
19) Larus pipixcan to Leucophaeus pipixcan.
20) Larus serranus to Chroicocephalus serranus.
21) Larus atricilla to Leucophaeus atricilla.
22) Larus modestus to Leucophaeus modestus.
23) Charadrius falklandicus to Anarhynchus falklandicus.
24) Charadrius collaris to Anarhynchus collaris.
25) Charadrius modestus to Zonibyx modestus.
26) Charadrius alticola to Anarhynchus alticola.
27) Charadrius mongolus to Anarhynchus mongolus.
28) Catharacta chilensis to Stercorarius chilensis.
29) Catharacta antarctica to Stercorarius antarcticus.
30) Catharacta maccormicki to Stercorarius maccormicki.
31) Patagioenas albilinea to Patagioenas fasciata.
32) Psittacara acuticaudatus to Thectocercus acuticaudatus.
33) Alexandrinus krameri to Psittacula krameri.
34) Ciccaba huhula to Strix huhula.
35) Ciccaba virgata to Strix virgata.
36) Macropsalis forcipata to Hydropsalis forcipata.
37) Hydropsalis maculicaudus to Antiurus maculicaudus.
38) Hylatomus schulzii to Dryocopus schulzii.
39) Hylatomus lineatus to Dryocopus lineatus.
40) Xenops rutilus to Xenops rutilans.
41) Antilophia galeata to Chiroxiphia galeata.
42) Myiodynastes solitarius to Myiodynastes maculatus.
43) Griseotyrannus aurantioatrocristatus to Empidonomus aurantioatrocristatus.
44) Xolmis coronatus to Neoxolmis coronatus.
45) Xolmis cinereus to Nengetus cinereus.
46) Xolmis dominicanus to Heteroxolmis dominicana.
47) Xolmis pyrope to Pyrope pyrope.
48) Phaeomyias murina to Nesotriccus murinus.
49) Phyllomyias burmeisteri to Acrochordopus burmeisteri.
50) Xolmis rubetra to Neoxolmis rubetra.
51) Hirundinea bellicosa to Hirundinea ferruginea.
52) Xolmis salinarum to Neoxolmis salinarum.
53) Polioxolmis rufipennis to Cnemarchus rufipennis.
54) Phylloscartes paulista to Pogonotriccus lanyoni.
55) Phyllomyias uropygialis to Tyranniscus uropygialis.
56) Tachycineta meyeni to Tachycineta leucopyga.
57) Turdus anthracinus to Turdus chiguanco.
58) Catharus swainsoni to Catharus ustulatus.
59) Basileuterus auricapilla to Basileuterus culicivorus.
60) Tangara sayaca to Thraupis sayaca.
61) Pipraeidea bonariensis to Rauenia bonariensis.
62) Tangara palmarum to Thraupis palmarum.
63) Corydospiza alaudina to Rhopospina alaudina.
64) Corydospiza carbonaria to Rhopospina carbonaria.
65) Microspingus pectoralis to Microspingus torquatus.
66) Saltator multicolor to Saltatricula multicolor.
67) Tangara preciosa to Stilpnia preciosa.
68) Sicalis uropigyalis to Sicalis uropygialis.
69) Ramphocelus bresilius to Ramphocelus bresilia.
70) Tangara flava to Stilpnia cayana.
71) Chionodacryon speculiferum to Idiopsar speculifer.
72) Ephippiospingus dorsalis to Idiopsar dorsalis.
73) Euphonia cyanocephala to Chlorophonia cyanocephala.
74) Tityra braziliensis to Tityra cayana.
75) Phalcoboenus chimango to Daptrius chimango.
76) Milvago chimachima to Daptrius chimachima.
77) Phalcoboenus albogularis to Daptrius albogularis.
78) Phalcoboenus megalopterus to Daptrius megalopterus.
79) Phalcoboenus australis to Daptrius australis.

Reduction of recognized species in Argentina: unification under new classifications

In some specific cases, the taxonomic update led to a reduction in the number of recognized species in Argentina. This happens when two species previously considered distinct are now classified as subspecies of the same species. Below are the most relevant cases:

• Podiceps juninensis is merged with Podiceps occipitalis.
• Patagioenas albipennis is now considered a subspecies of Patagioenas maculosa.
• Colaptes melanolaimus is merged with Colaptes melanochloros.
• Leptasthenura pallida is merged into Leptasthenura aegithaloides.
• Leptasthenura berlepschi is also merged with Leptasthenura aegithaloides.
• Syndactyla cabanisi is merged into Syndactyla rufosuperciliata.

It is important to highlight that the large number of changes is not due to recent scientific studies, but to the change in the taxonomic source adopted by EcoRegistros. That is, to the switch from the HBW and BirdLife Taxonomic Checklist v9.0 (2024) to AviList (2025). This adjustment process is not exclusive to EcoRegistros—many systems will need to gradually adapt to AviList, with impacts that will vary depending on how compatible their previous sources were. In our case, the change has been significant due to differences between the current BirdLife and AviList criteria.

Exceptions and future outlook: EcoRegistros' commitment to an inclusive taxonomy

Although EcoRegistros adopts AviList as its primary taxonomic source, it reserves the right to evaluate specific cases and apply well-founded exceptions based on scientific evidence or criteria aligned with regional reality and observer experience. These decisions aim to strike a balance between scientific rigor and practicality for system users. While EcoRegistros has always implemented an exception system to its primary taxonomic source, upon migrating to the AviList taxonomy, the number of exceptions was significantly reduced to just four.

Taxonomic exceptions adopted by EcoRegistros:

• Thalassarche steadi is considered a valid species.
• Cinclodes maculirostris is also recognized as a species by exception.
• Leucocarbo bransfieldensis is maintained as a distinct species.
• Leucocarbo georgianus likewise appears as a valid species in the database.

A decisive step towards global unification

With this implementation, EcoRegistros takes a firm step towards the standardization of species names at a global level, facilitating interoperability with other observation and citizen science platforms. After all, what is the point of a unified list if no one applies it? Adopting AviList early on, even before long-standing institutions like BirdLife International, demonstrates EcoRegistros' commitment to actively contribute to international taxonomic organization and the sharing of information with our community.

If this course is maintained, it is possible that future generations of naturalists and observers will not experience the difficulties we have faced in reconciling data between platforms. Of course, those who delve into the scientific literature will always find traces of the complex history of multiple names that have accompanied each species over time.

Useful links:

• Message from the EcoRegistros forum detailing all taxonomic changes applied in the global database:
  https://www.ecoregistros.org/site/foromensaje.php?id=77108
• Bird Taxonomy section in EcoRegistros where the exceptions are defined:
  https://www.ecoregistros.org/site/taxonomia.php