Ruby-crowned Kinglet

The Ruby-crowned Kinglet, Corthylio calendula, is a diminutive passerine that graces the North American landscape with its presence. This member of the kinglet family is adorned with olive-green plumage, accented by two white wing bars and a delicate white eye-ring. The male boasts a hidden gem—a vibrant red crown patch, typically concealed among the feathers. Both sexes are similar in appearance, save for this crown, and juveniles share the adults' plumage pattern. Among the smallest of North American songbirds, the Ruby-crowned Kinglet is a unique species, placed in its own genus, Corthylio.

Identification Tips

When observing these birds, look for the characteristic wing-flicking behavior and listen for their complex vocalizations. The male's red crown patch, though often hidden, is a key distinguishing feature. In flight, they exhibit rapid wing beats, and their overall appearance is a combination of gray-green upperparts and olive-buff underparts, with the distinctive white wing bars and eye-ring.

Habitat

The Ruby-crowned Kinglet favors spruce-fir forests for its breeding grounds. These forests are typically found in the northern reaches and mountainous regions of the United States and Canada.

Distribution

This migratory bird has a range that spans from northwest Canada and Alaska, all the way south to Mexico. During the breeding season, they inhabit the northern and mountainous areas, while in winter, they can be found in the southern United States and Mexico.

Behaviour

The Ruby-crowned Kinglet is an active forager, flitting through trees and shrubs in search of small insects and spiders. It is known for its agility, often hovering or even catching insects mid-flight. When agitated or displaying, the male may reveal its namesake ruby crown. These birds are also known for their fearless defense of the nest, engaging in distraction displays and mobbing potential predators.

Song & Calls

The kinglet's song is a complex and loud affair, especially considering the bird's small size. It consists of high-pitched notes, low trills, and a distinctive "galloping" phrase. While there is individual variation, the full song is typically heard from males, with females producing an abbreviated version.

Breeding

The Ruby-crowned Kinglet constructs a cup-shaped nest, which may be pensile or placed on a tree branch, often well-hidden. It lays up to 12 eggs per clutch, the largest number for a North American passerine of its size.

Similar Species

The Golden-crowned Kinglet is similar in size and behavior but can be differentiated by its coloration and the presence of black crown stripes. Hutton's Vireo and the Dwarf Vireo also share some visual similarities but are larger with stouter bills and legs, and lack the black bar on the wings characteristic of the kinglet.

Diet and Feeding

Primarily insectivorous, the Ruby-crowned Kinglet supplements its diet with fruits and seeds as available.

Conservation status

The IUCN lists the Ruby-crowned Kinglet as Least Concern, with population trends indicating an increase, likely due to the discovery and utilization of less disturbed northern territories for breeding.