St. Paddies Day got us musing about the color green in the bird world. Have you noticed that there aren’t a lot green-colored birds up here in our northern climes? In our wintery white world like we experienced this year, a green-colored bird trying to hide from predators might not last long. There are always exceptions, of course — remember the fa- out-of-normal range, bright green (immature) painted bunting that spent the winter at an Ocean Point feeder a few years ago? That bird was supposed to be in Mexico or maybe Cuba.

In those places and farther south, there are many more bird species that show green plumage. Parrots and parakeets are among the bird families with a preponderance of green and that occur in greatest diversity in warmer parts of the world. Many people don’t realize that the United States once had its own endemic species of parakeet, the Carolina parakeet, which occurred primarily in the southeastern U.S., occasionally north to the Great Lakes and Midwest. Amazingly, the final Carolina parakeet outlasted the last passenger pigeon by four years, passing away in 1918. Sadly, both of these last-of-their-kind individuals died in captivity in the Cincinnati Zoo.

One of the other bird families with much green is the hummingbirds. We have our beloved ruby-throated hummingbird in summer. A few other birds have green in their plumage, such as the green-winged teal with its little greenish wing bar (the breeding plumaged male has a green patch on the head, too), the green-headed male mallard, the iridescent greenish sheen on the male greater scaup. And some flycatchers, vireos, and some warblers are varying shades of green. If you look closely at a breeding-plumaged male common eider, you may see light green shading on the back of its otherwise white neck. Someone reported recently to the Maine birding listserve that they had seen a green-morph pine siskin near Bangor — an unusual greenish-tinted plumage variant of that species that we once photographed and videotaped at our own feeder a few years back.

Most of the green colors we perceive in birds are wholly or partly the result of feather structure, not pigmentation. Blacks, browns, reds, and orange colors in birds are typically the result of various pigments in feathers. But blues and greens are usually the result of feather structures. In parrots, the green color is a combination of structural components in the feathers that would make them look blue, but the feathers have yellowish pigments in them as well so that the combination makes them appear green.

Another interesting aspect of the plumages we perceive in birds: Increasing evidence shows that most birds can see much more in the ultraviolet spectrum than humans can. Some birds may display plumage characteristics that are only visible or are most vivid in the ultraviolet spectrum that we can’t see. What we see when we look at the ruby-throated hummingbird in the backyard may be quite different than what the other hummingbirds see!

Watch for more wearin’ of the green as our migrant species begin to arrive back to Maine in the coming weeks and months.