Bird names aren't always as simple as "chickadee," that bird at your feeder.

Officially, it's the black-capped chickadee, one of seven chickadee species in North America. The others are Carolina, mountain, gray-headed, boreal, Mexican and chestnut-backed.

All birds have Latin as well as common names, a scientific name used worldwide regardless of local designation. This enables clear understanding of which particular bird you're talking about, regardless of language. These names are used almost exclusively in scholarly publications, and also can be found in your ID guides, in italics just below the common name.

The Latin name for our chickadee is Poecile atricapillus. That's the name researchers would use here or in France or Cuba or China.

Poecile comes from the Greek poikil, meaning spotted, dappled, pied, many-colored. Atricapillus is Latin. Atri- means black or dark. Capillus means cap. Hence black-capped chickadee.

Scientific names come from a system created by a Swedish scientist, Carl von Linné (1707-1778). He is better and most appropriately known by the Latin form of his name, Linnaeus.

He was a botanist, physician and zoologist who described a formal system for naming organisms. With some modification, his original system is used today worldwide.

The system has eight classifications, each dividing into ever smaller parts. This is how it works for the chickadee:

Chickadees belong to the kingdom called Animalia (animals).

Then the phylum: Chordata (animals with a flexible spine).

Next, class: Aves (birds).

Then, order: Passeriformes (songbirds).

Then, family (common characteristics).

Then, genus (common characteristics that can be subdivided).

Then, species (capable of interbreeding).

There also are hybrids, two chickadee species interbreeding, creating subtle distinctions that make no backyard difference.

And there are subspecies, which break black-capped chickadees, for instance, into smaller categories. A literature search seems to indicate that telling one subspecies from another is hard work even for experts. Various authors found as few as 10 subspecies and as many as 35. We don't want to go there.

Who makes naming decisions? Linnaeus published what he called the law of priority. That means that the first published name of a genus or species takes precedence.

If you are the first to do that you get to choose the two-part scientific name. The first word is a noun designating group, no leeway there. The second part of the name usually is an adjective describing physical characteristics, as in the case of our chickadee.

However, there are options. If you wish, you can honor a friend or associate, or state an opinion. Lincoln's sparrow, Melospiza lincolnii, for example, was named by artist John James Audubon for a companion. Pacific-slope flycatcher, Empidonax difficilis, is aptly named because it is particularly difficult to identify.

Google often will explain the background of bird names. It's a birding adventure fit for a rainy, cold day.

Read Jim Williams' birding blog at startribune.com/wingnut.