Kinglets are small song birds found in the northern hemisphere. There are six species of kinglets, all in the genus Regulus. Two species, the ruby-crowned kinglet and the golden-crowned kinglet, reside in North America. The goldcrest is found in Europe and Asia, the firecrest in Europe and North Africa, the flamecrest in Taiwan, and the orangecrest on the Canary Islands.
As one of North America's smallest birds, kinglets are barely larger than hummingbirds. Measuring between 3.1 and 4.3 inches (9–11 cm) long, their maximum wingspans are 7.1 inches (18 cm). They weigh between 0.1–0.4 ounces (4–10 g).
Kinglets are olive colored, and species are mostly distinguish by their differently colored crests. For example, the male ruby-crowned kinglet has a bright red crest, which is often hidden. Golden-crowned kinglets have yellow-orange crests.
The ruby-crowned species also have eye rings, which help distinguish them from the golden-crowned species, which have eye stripes. The ruby and golden-crowned kinglets also differ in their songs. The ruby's notes seem to tumble over each other, whereas the golden's song is a more structured series of varying pitches.
Kinglets are sometimes considered a subspecies of old world warblers and are also similar to the titmouse. Additionally, many experts believe that all six kinglet species are not in fact distinct species. For example, some consider the flamecrest to be a subspecies of the firecrest, and the golden-crowned and goldcrest to actually be the same species.
Kinglets are constantly moving, flitting from branch to branch and frequently flicking their wings even when perched. This movement helps keep them warm in the cold environments where they often live. Unlike many bird species, kinglets migrate north in colder months, wintering in Canada and Alaska.
Kinglets are insect eaters and are considered extremely important predators in their ecosystems. These birds grab insects from the tips of branches or foliage or on the bark of trees. This type of feeding is called gleaning.
Hanging from tree branches, kinglet nests are deep and made from moss and bark that is glued together by spiderwebs. The nests are lined with feathers and grass. Females lay three to 11 eggs, which they then incubate for about two weeks.
Golden-crowned kinglets will lay two batches of eggs. Once the young hatches, the female will brood her chicks for a day and then pass off the care to her mate so she can lay another clutch of eggs. The male is then in charge of feeding both the chicks and his mate, as well as himself.
The red-crowned kinglet is the most common kinglet species in the North America. Whether red-crowned or golden, however, kinglets are considered common and their populations are increasing.