The White-breasted nuthatch (Sitta carolinensis) is a small songbird common across much of temperate North America. It is a noisy bird that changes its diet according to the season. The species enjoys a very wide distribution and its population is said to be increasing.
The adult male has pale blue-gray upperparts, a glossy black cap (crown of the head), and a black band on the upper back. The wing coverts and flight feathers are very dark gray with paler fringes, and the closed wing is pale gray and black, with a thin white wing bar. The face and the underparts are white. The outer tail feathers are black with broad diagonal white bands across the outer three feathers, a feature readily visible in flight. The female has, on average, a narrower black back band, slightly duller upperparts, and buffer underparts than the male. Her cap may be gray, but many females have black caps and cannot be reliably distinguished from the male in the field. In the northeastern United States, at least 10% of females have black caps, but the proportion rises to 40-80% in the Rocky Mountains, Mexico, and the southeastern U.S. Juveniles are similar to the adult, but duller plumaged.
White-breasted nuthatches occur across North America, from southern Canada to northern Florida and southern Mexico. In the eastern part of their range, these birds prefer to live in old-growth open deciduous or mixed forests, including orchards, parks, suburban gardens, and cemeteries. In the west and Mexico, they inhabit open montane pine-oak woodlands. Pinyon-juniper and riverside woodlands may be used locally where available.
White-breasted nuthatches are non-migratory and normally live in pairs in their territory year-round. In winter, however, they often travel with small mixed flocks of chickadees, titmice, and woodpeckers. White-breasted nuthatches are diurnal. They forage along tree trunks and branches in a similar way to woodpeckers and treecreepers but do not use their tail for additional support, instead progressing in jerky hops using their strong legs and feet. When seeking food nuthatches are able to descend tree trunks head-first and can hang upside-down beneath twigs and branches. They may occasionally feed on the ground, and readily visit feeding stations, especially for sunflower seeds, which they often take away to store. White-breasted nuthatches are very noisy birds having a range of vocalizations. The male's mating song is a rapid nasal 'qui-qui-qui-qui-qui-qui-qui'. The contact call between members of a pair, given most frequently in the fall and winter is a thin squeaky 'nit', uttered up to 30 times a minute. A more distinctive sound is a shrill 'kri' repeated rapidly with mounting anxiety or excitement 'kri-kri-kri-kri-kri-kri-kri-kri'; the Rocky Mountains and Great Basin populations have a higher, faster 'yididitititit' call, and Pacific birds a more nasal 'beeerf'.
White-breasted nuthatches are omnivores, eating insects and seeds. In winter they eat nearly 70% seeds, but in summer it is mainly insects. The insects consumed by these birds include caterpillars, ants, and pest species such as pine weevils, oystershell, and other scale insects, and jumping plant lice. At feeding stations, they eat nuts, suet, and sunflower seeds.
White-breasted nuthatches are monogamous forming pairs that remain together year-round until one partner dies or disappears. Pairs form following a courtship in which the male bows to the female, spreading his tail and drooping his wings while swaying back and forth; he also feeds her morsels of food. The pair establish a territory where it finds the nest cavity to lay eggs; it is usually a natural hole in a decaying tree, sometimes an old woodpecker nest. The nest hole is usually 3-12 m (9.8-39.4 ft) high in a tree and is lined with fur, fine grass, and shredded bark. The clutch is 5 to 9 eggs which are creamy-white, speckled with reddish-brown. The eggs are incubated by the female for 13 to 14 days prior to hatching, and the altricial (helpless) chicks fledge in a further 18 to 26 days. Both adults feed the chicks in the nest for about 2 weeks after fledging, and the male also feeds the female while she is incubating. Once independent, juveniles leave the adults' territory and either establish their own territory or become "floaters", unpaired birds without territories.
The White-breasted nuthatch is a common species with a large range and is not considered endangered at present. However, the removal of dead trees from forests may cause problems locally for this species because it requires cavity sites for nesting.
According to Partners In Flight resource, the total breeding population size of the White-breasted nuthatch is 9.2 million individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are increasing.
White-breasted nuthatches play an important role by controlling insect populations and dispersing the seeds of many plants throughout their ecosystem.
