H.J. Ruiz – Avian101

Ruby – crowned Kinglet

The Ruby-crowned Kinglet (Regulus calendula) is a very small passerine bird found throughout North America. It is a member of the kinglet family. The bird has olive-green plumage with two white wing bars and a white eye-ring. Males have a red crown patch, which is usually concealed. The sexes are identical (apart from the crown), and juveniles are similar in plumage to adults. It is one of the smallest songbirds in North America. The ruby-crowned kinglet is not closely related to other kinglets, and is put in its own subgenus, Corthylio. Three subspecies are currently recognized.

The kinglet is migratory, and its range extends from northwest Canada and Alaska south to Mexico. Its breeding habitat is spruce-fir forests in the northern and mountainous regions of the United States and Canada. The ruby-crowned kinglet builds a cup-shaped nest, which may be pensile or placed on a tree branch and is often hidden. It lays up to 12 eggs, and has the largest clutch of any North American passerine for its size. It is mainly insectivorous, but also eats fruits and seeds.

The ruby-crowned kinglet is a very small bird, being 9 to 11 cm (3.5 to 4.3 in) long, having a wingspan of 16 to 18 cm (6.3 to 7.1 in), and weighing 5 to 10 g (0.2 to 0.4 oz). It has gray-green upperparts and olive-buff underparts. It has two white wingbars and a broken white eye ring. The wingbar on the greater secondary coverts (closer to the wing-tip) is wider, and is next to a dark band. The kinglet has a relatively plain face and head, although the male has a scarlet-red crown patch, which is usually concealed by the surrounding feathers. The crown patch is rarely orange, yellow, or not present. Females are identical to males (except for the crown). Immature birds are similar to adult females, since young males lack a crown patch. The kinglet usually moves along branches or through foliage with short hops, and flies with bursts of rapid wing beats. It is constantly active, and is easily recognized by its characteristic wing-flicking. Its flight has been described as “swift, jerky, and erratic”.

Compared to the related golden-crowned kinglet, the ruby-crowned kinglet is slightly larger, more elongated, and has greener plumage. The bird can be mistaken for the Hutton’s vireo, which also displays wing-flicking, though less frequently than the kinglet. It can also be mistaken for the dwarf vireo in Mexico. However, both of the vireos are larger, have stouter bills and legs, and lack the kinglet’s black bar on the wings.

The ruby-crowned kinglet’s vocalizations are remarkably loud and complex for its size. Its song can be divided into three main parts: a series of high pitched notes (zee-zee-zee or tee-tee-tee), two to five low trills (turr or tu), and a repeated three note “galloping” phrase (tee-da-leet, tee-da-leet). However, there is variation in the songs of a given individual, and they often contain only one or two of the three parts. The third part is only sung by male birds; an abbreviated version is heard from the females. Other vocalizations of the ruby-crowned kinglet include alarm calls, simple contact calls, and begging calls produced by chicks.

Note: The Ruby-crowned Kinglet is # 218 on my List of “Lifers”

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© HJ Ruiz – Avian101