The nuthatches are a genus, Sitta, of small passerine birds belonging to the family Sittidae. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs. Most species exhibit grey or bluish upperparts and a black eye stripe.
All members of this genus nest in holes or crevices. Most species are non-migratory and live in their habitat year-round, although the North American Red-breasted Nuthatch migrates to warmer regions during the winter.
Nuthatches are omnivorous, eating mostly insects, nuts and seeds. They forage for insects hidden in or under bark by climbing along tree trunks and branches, sometimes upside down. They forage within their territories when breeding, but may join mixed feeding flocks at other times. Their habit of wedging a large food item in a crevice and then hacking at it with their strong bills gives this group its English name.
Nuthatches are compact birds with short legs, compressed wings. They have long, sturdy, pointed bills and strong toes with long claws. Nuthatches have blue-grey backs and white underparts, which are variably tinted with buff, orange or rufous. Although head markings vary between species, a long black eye stripe, with contrasting white supercilium, dark forehead and blackish cap is common. The sexes look similar, but may differ in underpart colouration, especially on the rear flanks and under the tail. Juveniles and first-year birds can be almost indistinguishable from adults.
Nuthatches are very vocal, using an assortment of whistles, trills and calls. Their breeding songs tend to be simple and often identical to their contact calls but longer in duration. The Red-breasted Nuthatch, which coexists with the Black-capped Chickadee throughout much of its range, is able to understand the latter species' calls. The chickadee has subtle call variations that communicate information about the size and risk of potential predators. Many birds recognise the simple alarm calls produced by other species, but the Red-breasted Nuthatch is able to interpret the chickadees' detailed variations and to respond appropriately.
It includes the Pygmy Nuthatch, Brown-headed Nuthatch, Red-breasted Nuthatch and the White-breasted Nuthatch.
