Ruby-Crowned Kinglet

Ruby-crowned kinglet, male, perched on a bird feeder
Scientific Name
Corthylio calendula
Regulidae (kinglets) in the order Passeriformes

Kinglets are very small, active, insect-eating birds that Missourians see in winter and during migration in spring and fall. Ruby-crowned kinglets are grayish olive, have white wing bars, and flick their wings as they flit around. Males have a red crown patch that they occasionally raise.

In adult ruby-crowned kinglets, the upperparts are grayish olive, with a white eye ring and two white wing bars (one long and one short and sometimes hard to see). The underparts are light olive and unmarked. The adult male displays a small red crown patch when singing, agitated, or disturbed. The song is a series of high “see-see-see” notes, followed by three descending “hew-hew-hews,” jumbled warbles, and a loud series of repeated bubbly chirping phrases. The call is an emphatic “chi-dit, chi-dit.”

Similar species:

  • The only other North American kinglet is the golden-crowned kinglet. The golden-crowned kinglet is smaller than the ruby-crowned kinglet, has an orange or yellow (not strongly red) crown, has black crown stripes, and has a different voice, with the first thin “see” notes notably ascending in pitch.
  • To distinguish kinglets from wrens and other small birds with bills like tweezers, note the kinglets’ very small size, tiny bill, short, thin tail, the males’ colorful crown stripe (which can be erected into a small crest during courtship or territorial displays), and comparative proportions of wing and tail lengths. Kinglets seemingly have no necks. Kinglets are also fast-moving, high-energy birds and seem nervous or even frenzied. They typically flick their wings as they flit around.

Length: 4¼ inches (tip of bill to tip of tail) (smaller than a warbler).

Where To Find

Statewide during migration; in winter, more likely to be seen in the southern half of the state.

Look for ruby-crowned kinglets in woodlands and shrubby edges. Kinglets continually flick their wings, which gives these very small birds a nervous appearance.

In fall, migrating kinglets are easily approached as they forage in the dry leaves remaining on a tree, under loose bark, or in the needles of a coniferous tree such as eastern red cedar, shortleaf pine, or Norway spruce. You may be fortunate enough to see one in a tree in your backyard. However, if you want to search for kinglets, you should visit a woodland area in a park, in the country, or in a nearby woods.

To see fall-migrating kinglets in the woods, listen patiently for the sounds of birds, and a mixed foraging flock may appear. These groups of active little birds — which may including titmice, woodpeckers, chickadees, and nuthatches — often include a few kinglets. Because of their tiny size, it may take a few minutes to find them. If you can determine the direction the flock is traveling, you might be able to stay with the flock until you have seen all the species present.

By wintertime, kinglets are less common in northern Missouri foraging flocks, and the ruby-crowned kinglet is rarely seen in winter except in the Bootheel lowlands.

In spring, northbound ruby-crowned kinglets appear about a week after golden-crowned kinglets and become most common when most migrating warblers are passing through Missouri — usually in late March through April.

Kinglets are active foragers in woodlands and shrubby edges, as they hop around branches and flutter among leaves seeking insects, spiders, and some seeds. They frequently hover as they search a leaf or branch for hidden insects. In winter, they may visit bird feeders for some seeds and suet.

See Habitat and Conservation and Ecosystem Connections for more about kinglets in mixed-species foraging flocks in fall and early winter. These flocks are organized so that the different species forage in slightly different locations (such as tree trunks, outer branches, lower branches, leaf litter, or among curled leaves) for slightly different foods.

Common transient; as a winter resident, uncommon in southeast Missouri and in the Ozarks, and rare in northern Missouri.

Taxonomy: Once classified alongside the other kinglets in genus Regulus, the ruby-crowned kinglet is different enough to be placed in its own genus, Corthylio.

Life Cycle

Present in Missouri from September through mid-May; populations are highest in October and November, and in late March through April.

Both species of kinglets arrive in mid- to late September from their breeding range in the coniferous forests of the northern United States and Canada. In early fall, they join the mixed-species foraging flocks that roam Missouri’s deciduous forests in search of insects, larvae, and eggs. By winter, kinglets are less common in the northern half of Missouri, and the ruby-crowned kinglet is rarely seen in winter except in the Bootheel lowlands.

Kinglets migrate back north in late March and early April, starting with the golden-crowned kinglets. Ruby-crowned kinglets arrive a week or so later and are common when most warblers are passing through Missouri.

In their breeding range, ruby-crowned kinglets construct round, elastic nests high in trees, building them out of a variety of fine materials such as grasses, spider webs, feathers, fur, and mosses. There is only 1 brood a year. A clutch comprises 5–12 eggs, which are incubated for about 13 days. After hatching, the young remain in the nest for another 16–18 days before they start to fledge. Lifespan can exceed 8 years.

The ruby-crowned kinglet is a birder’s bird: it’s tiny, lively, with a song much louder than you’d expect, given its size. If you’re lucky, you may see the male’s brilliant red crown. Birdwatching is a kind of sport that gets you outdoors at the crack of dawn and exhilarates you with the beauty and wonder of nature.

One of Missouri’s master birders was former state ornithologist Brad Jacobs, who gave us excellent advice for how to watch the mixed-species fall foraging flocks that kinglets often join:

“In order to observe forest birds in the nonbreeding season, one must have patience and a good ear. By walking quietly through the woods and listening carefully, you may hear a foraging flock or see some of the birds as they move into the area near you. Once you have located one or two birds, determine the direction in which they are moving and start traveling in the same direction. Even if you initially cannot see many of the other members of the foraging flock, you will likely find them in the next five to ten minutes. The key is simply to watch the behavior of these diminutive forest dwellers and follow them as they move about; if you keep looking, you will probably find the rest of the flock. If you decide to stop following the flock and go elsewhere, you may not see another flock for some time.”

The mixed-species foraging flocks that kinglets participate in are connected to habitat and other animals in many ways.

In Missouri and in other parts of the world, foraging flocks often organize themselves around a drab-colored species with a loud ringing voice. In Missouri this is usually the tufted titmouse.

Birds in mixed foraging flocks are usually insectivores, and usually they would compete with each other. But these flocks apparently help their participants in a variety of ways:

  • It may increase the ability to find food when it is scarce. The more individuals searching for food, the less time any one individual spends searching the habitat already searched by other birds.
  • A greater number of birds creates more pairs of eyes to look out for predators. And being an individual in a flock decreases a bird’s odds of being singled out and captured by a predator.
  • Flocking may allow some birds to forage in areas where they would not be able to forage as an individual. For example, chickadees or titmice might be driven off the winter territory of a red-headed woodpecker if they are foraging alone. However, a mixed-species flock in the woodpecker's territory causes a different reaction.

Missouri’s early-winter woodland foraging flocks are not unique. Similar mixed-species foraging flocks occur in grasslands, on mudflats, on water, or in shrub habitats, each with different suites of species. They occur in other parts of the world, too. In tropical America, for instance, foraging flocks often include both North American migrants and tropical resident species. In this case, the flocks usually include many more species and individuals than they do in our northern latitudes.

Although all the bird species in the foraging flock may be insectivores, they each exploit a different part of the food resources in the forest:

  • Nuthatches, the upside-down birds, creep up and down tree trunks and on the tops and bottoms of branches.
  • Kinglets search in rolled-up dried leaves still on trees or on the ground for insects and spiders.
  • Chickadees search along branches, in leaves, or among next year's leaf buds.
  • Downy woodpeckers forage along tree branches and tree trunks, probing cracks and looking under loose bark.
  • Brown creepers spiral up the trunks of rough-barked trees, searching for insects in cracks and under bark — they may climb high in the tree before fluttering to the ground to begin searching the next tree from the bottom upward.
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Similar Species
About Birds in Missouri

About 350 species of birds are likely to be seen in Missouri, though nearly 400 have been recorded within our borders. Most people know a bird when they see one — it has feathers, wings, and a bill. Birds are warm-blooded, and most species can fly. Many migrate hundreds or thousands of miles. Birds lay hard-shelled eggs (often in a nest), and the parents care for the young. Many communicate with songs and calls.