Taxonomy

by Mike Stiles

In most field guides the birds are arranged in taxonomic order, and the first birds that appear are older evolutionarily than the subsequent bird groups. In this arrangement, groups of birds that appear together are more closely related than birds that appear widely separated in the guides.

The taxonomic order is set by the American Ornithologist's Union (AOU), and that order has been in great flux recently. Due to DNA sequencing, the relationships among bird groups has changed drastically, and, as you can imagine, is debated even among the scientists doing the studies.

As a refresher, I will mention that since the 18th century, all living things have been given Latin genus and species names. As an aside, the genus is always capitalized, and both are always in italics. This is the most basic and smallest division in taxonomic nomenclature. For example, the genus of American Robin is Turdus and the species epithet is migratorious, and is in the family Turdidae. Similar families are gathered into the order Passeriformes (perching birds), and all birds are in the class Aves.

In this simplistic article on taxonomy I will just mention that there are also divisions called superorder, suborder, parvorder, superfamily, subfamily, and tribe--each with its own corresponding suffix, but will leave it to the reader to delve further if desired.

There have been some recent changes in the arrangement of the largest groups (orders) in the field guides which shows some interesting relationships. For decades the loons and grebes have ruled the first pages of the guides as the most ancient group, and are now replaced by the ducks and then followed, remarkably, by the New World quails, pheasants, grouse and ptarmigan. Loons and grebes have "risen" to third place.

It was found recently that our vultures are essentially storks, so the storks now precede vultures in the book. In one dramatic move the falcons will no longer be near the hawks and eagles but will be moved toward the center of the guides between the woodpeckers and the parrots. This change is not even in the latest edition of the field guides.

Sparrows, long delegated to the back of the book, are now followed by such birds as grosbeaks, buntings, blackbirds, and finches, to name a few.

Not only have the larger orders been rearranged lately, but there also have been changes within families, and even changes on the generic levels. In one striking example our North American warblers have been reworked. The genus Dendroica, was once our largest genus of wood warblers that contained 21 species from Yellow Warbler to Cerulean Warbler. To it was added the parulas, American Redstart, and Hooded Warbler, and then the entire genus renamed Setophaga. You may read the entire story at ABA Birding.

The Yellow-breasted Chat, currently placed in field guides with the warblers, and long considered an outlier due to its size and biology, is thought to belong somewhere near the blackbirds. Current studies have not been able to fully understand the bird's taxonomic placement, but have concluded it definitely is not a warbler.

What does this all mean to you, the casual birder? Not much really. It is very interesting, and a bit confusing at times, and forces some of us to buy the latest field guide with the latest nomenclature. In that respect, it's a definite boon to field guide publishers. The old curmudgeon in me wants them to just leave it alone, mainly because I have enough things I'm forgetting already, but I guess it doesn't hurt to shake things up a bit. From time to time.

Peregrine Falcon Image by Nick Todd

All content copyright Slo Coast Journal and Mike Stiles. Do not use without express written permission.
Burrowing Owl on Banner by Cleve Nash