Now that you've had a chance to look at the new version of our checklist (see Wings Over Dutchess, January 2004), you know that the most obvious change is in the placement of the Waterfowl and Gallinaceous Birds before Loons.  But upon closer inspection, you may have noticed a couple of name changes as well.  The Common Snipe has become Wilson's Snipe and our beloved Rock Dove is now a Rock Pigeon.

In Part 1, we talked about checklist order and its relationship to taxonomy.  In Part 2, we'll address species name changes and why they occur.  By way of review, on our checklist we follow the taxonomic order and nomenclature set forth by the American Ornithologists' Union (AOU), which is generally regarded as the authority for North and Central America.  In other countries and on other continents, there are similar bodies that determine species order and naming.  For example, in England there is the British Ornithologists' Union (BOU).  Although these groups cooperate, they are independent of each other, and thus we find differences in some common names found on their checklists.  For example, we have Loons while the British have Divers—but on any continent ornithologists know this order of birds as Gaviiformes.

Ornithologists are well served by scientific names and have no real need for the common names that birders use in their communications.  But imagine what fun it would be to learn and use only scientific names!  Because of the obvious difficulties this would present to the vast majority of birders, and to facilitate communications in general, official common names are set forth by the AOU and similar authorities elsewhere in the world.  Once a name is decided, it is generally permanent, but sometimes names are changed.  While many name changes are easily explained and accepted by birders, others may raise an eyebrow here or there.  Why, you may ask, do names have to change when they work perfectly well?  What was wrong with "Common Snipe"? And why did "Rock Dove" have to change to "Rock Pigeon"?  We spend years learning all these names and then they change!   "Solitary Vireo" was just fine, but a while back the AOU decided to change that one to "Blue-headed Vireo."  The examples seem endless.

Sometimes, a new name is simply deemed to be more appropriate than the existing one.  This is the case with "Rock Pigeon."  This species really is more of a pigeon than a dove.  So it makes more sense to call it that.  The new name better reflects the relationship between this species and others that are similar.  A Rock Pigeon is much more like a Band-tailed Pigeon (which can be found in the western US) than it is like a Mourning Dove.  The AOU made the change for this reason, and to conform to the same name change that had already been made by the BOU.

In many cases, however, the new name is the result of a "lump" or a "split."  As ornithologists study birds, they sometimes decide that the taxonomy needs to be modified in order to clarify or correct a species' (or several species') status.  A fundamental issue in this regard is the meaning of the word "species."  This subject is fraught with lively debate and is far from settled. Simplistic definitions have fallen far short, and opinions differ on the criteria required to establish independent species status.  At one time, two animals were considered to be of the same species if they bred with each other and produced offspring that could reproduce.  But any intermediate birder can cite examples in which two different species hybridize successfully.  In truth, the concept of "species" is a human invention, something that makes it easier for us to classify the creatures and understand the world around us.  However, the unstoppable march of evolution will always blur the lines between certain species and force humans to reconsider previous taxonomic decisions.  Even if perfectly executed, a taxonomy represents no more than a snapshot in time.  So we are back to our evolving checklist with its sequence changes, lumps, and splits.

Lumps and splits occur when species definitions are determined to be incorrect.  Sometimes two distinct species are found to be so closely related that they are actually only one species.  In this case, the two species are "lumped" together and given a single species name.  In other cases, what was thought to be a single species is found to contain two or more populations that are sufficiently different from each other that they each merit distinct species status.  When taxonomists make this kind of change, it is known as a "split."  In recent years, splits have been more frequent than lumps.

Looking at our recent checklist changes, Wilson's Snipe got a new name because Common Snipe (Gallinago gallinago) was split into two distinct species.  The newly designated Wilson's Snipe (Gallinago delicata) is the American bird, while Common Snipe (Gallingo gallinago) is its Eurasian counterpart.  Interestingly, these two birds were listed as separate species years ago, were later lumped together as Common Snipe, and now have been split again.  The same thing happened with one of our colorful local birds.  Years ago, there was a western species called "Bullock's Oriole" and an eastern species called "Baltimore Oriole."  Then they were lumped into one species, Northern Oriole.  More recently, Northern Oriole was re-split into Bullock's and Baltimore!  Getting back to our Solitary Vireo, we now call it Blue-headed Vireo in our area because the species was split three ways, into Blue-headed, Plumbeous, and Cassin's Vireos.  Take a look at a recent field guide and compare these three.

If you keep a life list, you probably like hearing about species splits, because they can sometimes get you a new life bird in an instant.  Many American birders who had traveled in Europe, for example, gained a lifer when Common Snipe was split, because they now learned that they had seen a different species in Europe from the one they had seen in the U.S.  On the other hand, sometimes we just have to take our lumps and lose a lifer when two species on our list are determined to be one!

Most birders take these changes in stride.  Others simply ignore them.  Still others are vocal in their protest, saying that the authorities are in cahoots with the field guide publishers, who regularly churn out new editions in response to taxonomic and naming changes.  Some organizations have recommended that their checklists be left alone until the dust settles.  But one thing is certain:  After the dust settles, it will eventually be stirred up again.

To me, all this change is exciting.  It reflects progress and learning, the result of scinetists' successful efforts to gain new knowledge of the world around us.   Some taxonomic changes are made on the basis of morphological, geographic, vocalization, and other studies.  At the same time, new methods of DNA analysis represent a major contributing factor in the taxonomic upheavals that have taken place during the past decade or so.  Learning about the latest changes gives us a better understanding of the scientific process and of the progress that ornithologists make as they learn more and more about our feathered friends.

References & Resources
American Ornithologists' Union.  The AOU Check-list of North American Birds, 7th edition, as modified by 42nd, 43rd & 44th Supplements.
Clements, James (2000) Birds of the World, a Checklist, 5th ed. Ibis Publishing Company.
Charles Sibley and Burt Monroe, Jr. (1991) Distribution and Taxonomy of Birds of the World. Yale University Press.

On the web:
American Ornithologists' Union (2003).  Online list:  The AOU Check-list of North American Birds, 7th edition, as modified by 42nd, 43rd & 44th Supplements.
Ornithology.com. Bird Names
Bird Studies Canada. Avibase-The World Bird Database