Arctic bluebird
The Mountain bluebird, also known as the Arctic bluebird - is a small thrush that is easily identified by the vivid bright blue plumage of the male. In fact, this species has the bluest plumage out of all the North American bluebirds. The female is mainly gray but has a bluish tint, particularly on her wings and tail. She also has a white eye-ring, lacking in the male, and some females have a light reddish-brown color on their breasts and throats. Juveniles look like females but with slightly duller and darker upper parts, and a scaly effect, especially on their throat and breast.
These birds breed as far north as eastern and central Alaska, and south through central and western Canada (western Manitoba and southern Yukon) to areas in the west of the US (east of the Rockies). Mountain bluebirds can be found in some states year-round, however, some populations generally migrate south to Mexico in the winter and north into western Canada and even Alaska in the summer. Mountain bluebirds breed in grassland where there are scattered shrubs and thickets, tree-line tundra and clear-cuts, and prairie forests. They need cavities to nest in. They winter in flat grassland that features some trees and bushes, meadows with trees and hedges, lowland, farmland, and different types of forest.
During the breeding season in spring and summer, Mountain bluebirds usually are seen alone, in pairs, or - at the end of the breeding season - in family groups of a few members. They are diurnal and forage from perches, as other bluebirds do, snatching food from the ground, from vegetation, and in mid-air. They are excellent foragers in the air, hovering kestrel-like before they drop onto their prey, or catch insects on the wing. Darting flight and hovering require 8 to 4 times as much energy as does hunting from a perch, therefore they tend to use these methods when food is scarce. Apart from migration, Mountain bluebirds perform movements linked to the availability of fruit. The birds travel in flocks of as many as 30 individuals, sometimes more. During winter, they often form loose flocks with other species of passerine. The call of Mountain bluebirds is a thin 'few'; while their song is warbled high 'chur chur'.
Mountain bluebirds are carnivores (insectivores) and herbivores (frugivores). During the summer, their diet consists of insects; while, in the winter months they eat mostly berries (like Juniper berries, Russian-olive berries, elderberry, etc.) and fruit seeds (such as mistletoe seeds and grapes, just to name a few).
Mountain bluebirds are monogamous and form pairs. At the start of the breeding season, males are the first to arrive at the breeding grounds. They select a nest site, a cavity in a tree, or a rock crevice. The females then arrive, and to attract a female, a male flies around the site of the nest while calling. April to September is the breeding season. This species generally produces two broods. The building of the nest is done by the female, sometimes with help from the male, which will guard her or bring some materials. The female lays 4-8 pale blue eggs and incubates them over 13-14 days. Both parents feed, strongly protect and defend the chicks. During this time they are often very aggressive. The young fledge at 18-21 days and depend on their parents for another 3 weeks to 2 months.
Mountain bluebirds are quite common and they are not currently threatened. Their populations, however, are declining in places where trees are not big enough to provide natural cavities for nesting, and where agricultural and forestry practices have reduced the number of suitable nest sites. Competition is high for sites among cavity-nesting birds that can’t excavate them by themselves. Mountain, western, and eastern bluebirds compete for nesting boxes in places where their ranges overlap. European starlings, House sparrows, and House wrens are also fierce competitors with bluebirds for nest sites.
According to the IUCN Red List, the total population size of the Mountain bluebird is 6,000,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are increasing.
These small birds play an important role in the ecosystem they live in. Due to their insectivorous diet, they are helpful in controlling insect populations.
