[by Chuck Almdale]

It’s not as dire as the title implies, but reportedly the proponents of the four major avian taxonomic checklists in the world have been negotiating among themselves to reconcile the many differences between their lists, in order to arrive at One List, hereafter to be known as AviList.

I’m not shocked to learn this but at the same time I didn’t know people were closing in on accomplishing it. As diehard readers of this blog will easily recall, we posted a long piece about the Four Different Checklists of the Birds of the World back in March 2019. At that time the numbers looked like this:

Total recognized species:

• BirdLife Int’l/Handbook of Birds of the World – 11,126 species
• International Ornithological Congress (IOC) – 10,896 (230 fewer than BirdLife)
• Clements/eBird – 10,585 (541 fewer than Birdlife, 311 fewer than IOC)
• Howard & Moore – 10,175 (951 fewer than BirdLife, 721 fewer than IOC, 410 fewer than Clements)

Total species recognized by at least one of the four lists was 11,524, of which 86.5%% or 9,968 species were accepted by all, leaving 1,556 (13.5%) in dispute. The breakdown of that 1,556 was:

• 496 species, or 4.3% of the total, are recognized by three taxonomic authorities.
• 362 species, or 3.14%, are recognized by two authorities.
• 698 species, or 6.1%, are recognized by a single authority only.

Checklist agreement was as follows:

• BirdLife Int’l: 89.6% of species shared with all others; 5.6% shared with one or two other lists; 4.8% unique to itself.
• Clements: 94.2% of species shared with all others, 5.6% with 1-2 other lists, 0.21% unique to itself.
• IOC: 91.5% of species shared with all others, 7.4% with 1-2 other lists, 1.13% unique to itself.
• Howard & Moore: 98% of species shared with all others, 1.8% with 1-2 other lists, 0.2% unique to itself.

That’s where it stood six years ago, and that’s what the ornithological taxonomists had to deal with in order to reconcile that mess.

Word has it that as of June 11 2025, three of the lists (Howard & Moore the exception) have reconciled their differences. The AviList checklist v2025 (perhaps also version 15.1) lists:

Species	11,131
Subspecies	19,879
Orders	46
Families	252
Genera	2,376

The last time I checked eBird, last fall, they had 11,017 species, so now there’s another 114 species I’ll probably never see. Plus a new family. Which ones are they? Figure that out, write it up (including scientific name and breeding range would be very nice to include), send me the list and I’ll post it and give you the credit. Fame and fortune for you will no doubt swiftly ensue.

This article from the Birding Ecotours website was just sent to me. It’s worth reading to catch up on what’s up, including topics like “biological species concept” which is critically important to us all, especially those who wish to have viable offspring someday.

Birds of the World website doesn’t add much, but here it is.
Same thing for Birdlife International here.

After that, go to the AviList website and poke around. You can download, for free, Avilist v2025 in Extended (.xlsx) at 8.7 MB, and Short (.xlsx) at 5.1 MB, and then while away the hours seeing what’s what. I haven’t yet screwed up my courage to tackle that.

Then toss out all your old field guides, handbooks, bird photo books, checklists and lifelists and start over.
Just kidding. They’re mostly still useful. Just hope that the dingbats who want to  cancel all eponymous bird names find something else to waste their time on and stop adding to our troubles and annoying everyone.

There. That takes care of your weekend.