Words and their meanings evolve over time, they change across geography, and they change among different groups of users. To describe a popular carbonated beverage in this country, for example, you will hear the term “pop,” you will hear the term “soda,” and you will hear the term “Coke,” depending on where you are. They all mean the same thing; it’s just called something different by different speakers.

The naming of birds is an interesting subject falling along these wavering lines of usage. There is the “official” common names given to birds (by the American Ornithologist’s Union), and there’s the not-so-official names commonly in usage among the population.

Officially, Lanius ludovicianus is called a loggerhead shrike. Among the colloquial names given this bird by others is butcher bird, for its habit of hanging its dead prey on barbed wire or other thorny projections. Same bird, different name.

Group names are another area where there is often quite a bit of wiggle room. Seagull is a commonly used generic term describing any of a family of birds known as gulls, although none is officially called a seagull and many species are found far from any ocean. Sparrow is another example. Just about everyone has uttered this word without knowing exactly what a sparrow really is. Also coming to mind is a collective term used (by both science and common users) to corral any of the eagles, hawks, falcons, or vultures into one group: hawks.

I started thinking about this the other day as I was taking a walk through a neighborhood and heard the familiar singing of a house finch. The word finch is used quite frequently among both avid bird watchers and casual ones. It might have been Charles Darwin who brought this relatively arcane word for a group of birds into more common usage by studying the finches of the Galapagos Islands extensively, ultimately publishing “On the Origin of Species” in 1859, and helping to launch a revolution in biology. I’ve heard – and likely used – phrases like “finch-like song,” finch-like beak,” or “finch-like appearance.” It got me wondering, just what is a finch?

Officially that is.

As we step down the classification of organisms starting with kingdom, we eventually get to the class of feathered, egg-laying critters called aves (birds). Within this class are several orders including the one we are interested in: passeriformes, or perching birds. This large order contains more than half of all the bird species in the world. These are the species we are likely most familiar with as we encounter them virtually every day. Birds within passeriformes are also commonly called songbirds.

Order passeriformes consist of about 23 even more closely related groups called families. True finches are currently placed in the family Fringillidae. It’s here things get a little murky.

Science, despite what some would have us believe, is not “settled.” True science welcomes challenges to dogmatic beliefs and incorporates new evidence into currently held truths, ever ready to change as newer, more accurate data becomes known. No more so is this evident than in the biological classification of birds.

Opinions have changed as new information has become available to scientists. Modern DNA analysis has certainly played a role in this ongoing musical chairs. Those of you at home with even fairly recent field guides might be surprised to learn, for example, that the falcons are no longer considered in the same order as hawks and eagles; instead they’ve been given their own, falconiformes, and set apart.

But back to true finches, a group of birds that are mostly seed-eating, with conical bills, and found more so in the Northern Hemisphere. Like the falcons, it wasn’t very long ago when the sparrows were considered finches. The Northern cardinal was there, too. Not anymore.

With the current classification, there seems to be rather few true finches to be found locally. As I scan the list, I find perhaps eight species. Purple finch, house finch, red crossbill, white-winged crossbill, common redpoll, hoary redpoll, pine siskin, and American goldfinch are the only ones to be seen here with any regularity.

Curiously, as common as the word “finch” is among the populace, there are very few actual examples to point to. Officially that is.

Corliss is a West Fargo resident, avid birder and North Dakota Game and Fish volunteer instructor. He serves as a corporate pilot for Forum Communications.