While talking to a friend on the phone last week, I leaned back and looked out the window, and my eye caught some flittering movement in the blue spruce tree just outside the window. It was a ruby-crowned kinglet. Of course, by the time I hung up and found my binoculars, it had flown.

How did I know it was a ruby-crowned kinglet? Well, it was a very small bird, and the kinglets are the smallest bird we can see here except for hummingbirds, and I knew it was not a hummingbird. The wood warblers and the pine siskens are almost as small, and it was flitting about from branch to branch like a warbler, but it also was flittering its wings repeatedly like a kinglet. It was olive green, not brown, so that ruled out the brown creeper. I also noticed it had a clearly defined eye ring, not an eye line, so that ruled out a red-eyed vireo or a golden-crowned kinglet.

There are only two kinglets to be seen here — the golden-crowned has a light eye line, and the ruby-crowned has an eye ring. Thus, it was that simple to know I had seen a ruby-crowned kinglet. Tipping the scales at 2 ounces, the kinglets are the only bird we have that approximate the weight of a hummingbird.

The Colorado Breeding Bird Atlas shows that the ruby-crowned is the more common of the two, and they are both found most commonly in the mountainous half of the state. This is because they prefer the evergreen forest for nesting. The ruby-crowned kinglet will on occasion nest in a mixed forest of deciduous trees and evergreen. Their preference is the spruce/fir forest. The ruby-crowned kinglet migrates from here in September and October when insects become hard to find. Although both kinglets are insect eaters, the golden-crowned must find some insects that are available all winter, for they do not migrate but stay here in the dark, dense, old-growth spruce/fir forest.

I have seen both kinglets here in the yard but have never found a nest. The golden-crowned may show up most any time, for they wander about a bit except when they are nesting. The ruby-crowned migrates into Mexico and returns here each year during the first week of May.

The golden-crowned weaves a pendant nest much like an oriole but a bit smaller; the bottom part is often anchored to a twig from the branch below, perhaps to prevent too much swaying. The ruby-throated kinglet builds a well-woven nest, but it is not pendant; it is usually placed on the top of a limb, right up against the tree trunk. This makes it hard to see, for the outside is covered with bits of bark, lichen and other plant material.

Kinglets nest from Alaska across the Canadian forest to Nova Scotia and southward in the mountains to North Carolina and in the western mountains into Mexico. Nests have been found as low as 8,000 feet and as high as 11,000 at timberline. The ruby-crowned kinglet is more likely to nest lower down in the tree, or even in a tall shrub, while the golden-crowned are inclined to be 30 feet up in an old spruce tree.

The ruby-crowned kinglet has one of the loudest spring songs of any of the small birds. I could not believe that such a loud song came from such a tiny mite. The first few notes sound like the “what cheer” notes of the cardinal, but then it turns into a jumble of notes similar to its call notes but much louder. The call notes used the rest of the year are high, fine notes that I can no longer hear. In the many field guides they are described as low, chickadee-like chatter.

If you hear some very high, fine notes coming from the top of a spruce tree, think kinglet and scan the top branches until you find the little king. The golden-crowned kinglet has a flame-colored crest, banded with yellow, then a line of black and then the white eye line. The female does not have the flame central crest; just the entire crown is yellow. The ruby-crowned kinglet has a pure red crown, which he may keep covered, but if alarmed he raises this crest. If you are lucky enough to see it in the sunlight, it is as scintillating as any ruby. It is fit for a king or a kinglet.