I was walking along a lake, part of the Okhla Bird Sanctuary in New Delhi, India, when I spied a familiar duck. Could that be a Green-winged Teal? But after looking through my field guide, I discovered that Green-winged Teal wasn’t one of the options. There was, however, an illustration of a Common Teal that looked similar, so I jotted down the name and, for insurance, snapped a photo of the bird:

When I got home, I set about entering all the birds I had seen into my life list. (I’m enough of a nerd to keep my own Excel list, along with my eBird account.) I typed “Common Teal” into my search box, but came up empty. What? No Common Teal? That’s when I turned to Google and learned that some ornithologists call Anas crecca a Eurasian Teal, which was on my master list, and still others name it a Eurasian Green-winged Teal.

To further complicate things, the master list I am using (Clements) called our American Green-winged Teal a subspecies of the Eurasian Teal, Anas crecca carolinensis. However, as Wikipedia points out,

The green-winged teal (Anas carolinensis or Anas crecca carolinensis) … was considered conspecific with the Eurasian teal (A. crecca) for some time but the issue is still being reviewed by the American Ornithological Society [AOS]; based on this the IUCN and BirdLife International do not accept it as a separate species at present. However, nearly all other authorities consider it distinct based on behavioral, morphological, and molecular evidence.

(When I looked up the duck in the AOS list, it referred me to the Cornell Lab of Ornithology website. Does this mean that the lists match?)

Talk about confusing!

When I started birding, I was told that there are approximately 10,000 bird species in the world. I assumed that most people were in agreement just what those 10,000 species were. I was further impressed by the seeming consensus on common names (quite different from the world of botany, which has myriad replications and is currently in turmoil). Well, now I know better. There are several world lists of bird species, and they’re not at all the same.

It wasn’t just the duck. Since I started birding in 2004, I’ve had the opportunity to travel to a variety of places overseas—Swaziland (now called Eswatini), South Africa, Australia, Singapore, India—and I’ve picked up the “best” field guide each time. I dutifully wrote down the name given for each bird I saw. But when I returned home, I realized that the local common name doesn’t always match the various “official” common names.

Sometimes, it’s as simple as spelling. Is this a Grey Fantail or a Gray Fantail? The Australians (and other British-influenced places) spell it the first way, while lists influenced by us Americans spell it the second way.

Hyphens and capital letters cause a lot of grief. Is it a Cuckoo Shrike, a Cuckoo-shrike, a Cuckoo-Shrike, or a Cuckooshrike? The lists (and field guides) disagree.

And then, is that particular Cuckooshrike a Yellow-eyed Cuckoo-shrike or a Barred Cuckooshrike? (It’s the same bird, Coracina lineata.)

Sometimes, it’s the second names that are very different—when I went to look up my Red-browed Finch sighting, I discovered that my list called it a Red-browed Firetail. My Blacksmith Lapwing was listed as a Blacksmith Plover.

As long as I stick to the ABA bird list, there’s no confusion. But as I venture farther afield, I have to make a decision. Do I continue to use The Clements Checklist of the Birds of the World? After all, Cornell’s involvement is a good endorsement.

But what about  The Howard & Moore Complete Checklist of the Birds of the World, 4th Edition, or the Handbook of the Birds of the World, “an online comprehensive resource for all the birds of the world” that “contains the contents of the acclaimed 17-volume Handbook of the Birds of the World (HBW) series” and is available by subscription. Or I could use the IOC list, which “complements three other primary world bird lists [those just mentioned] that differ slightly in their primary goals and taxonomic philosophy.” (It would be helpful to know what those primary goals are.)

There’s more. Avibase is a list maintained by Denis Lepage and hosted by Bird Studies Canada, which is a co-partner of Birdlife International. I searched but couldn’t figure out what Wikipedia bases its list on. Finally, there’s the Sibley-Monroe checklist and the Sibley–Ahlquist taxonomy. Their work, based entirely on DNA studies conducted in the 1970s and 1980s, yielded a list that is quite different from everyone else’s.

Of course, no matter which list you choose to use, it will be constantly updated as new birds are discovered and current species are lumped and split. There’s also the issue of regional common names—are the local names more or less “valid” than a name bestowed by scientists from another place? And now we’re getting into political correctness. I never realized that birding could be so controversial!