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Sitta carolinensis Latham, 1790
White-Breasted Nuthatch
Family: Sittidae

Species account author: Jamie Fenneman
Introduction to the Birds

Photograph

© Tim Zurowski     (Photo ID #10349)

Map


Distribution of Sitta carolinensis in British Columbia.
(Click on the map to view a larger version.)
Source: Distribution map provided by Jamie Fenneman for E-Fauna BC

Species Information

Adult male
The upperparts are wholly pale blue-grey to medium-grey. Wings similarly blue-grey or medium-grey, with variably contrasting (depending on subspecies) black inner webs on the wing coverts and flight feathers and narrow whitish tips to the median wing coverts, forming a thin pale wing bar. Tail short and squared, with blue-grey or medium-grey central feathers and blackish outer five feathers, with bold white tips on the outer 3-4 pairs of feathers (diminishing in size towards the central tail feathers). Underparts whitish, often faintly tinged with buff on the lower breast and belly, with rufous or chestnut mottling on the undertail coverts and lower belly and a variable greyish wash on the flanks (fairly extensive in some subspecies). The face and throat are white, sharply contrasting with a black cap that extends from the forehead and crown down the nape and onto the upper back (where it contrasts sharply with the grey upperparts). The iris is dark, the sharp-pointed bill is dark grey to blackish with a pale blue-grey base to the lower mandible, and the legs and feet are dark grey.

Adult female
Very similar to the adult male in all subspecies, but averages slightly duller and browner/buffier. Best distinguished from the male by the medium- to dark grey (rather than black) cap, although some individuals (especially in western subspecies) can show a dark blackish cap similar to the male.

Juvenile
This plumage is held into August of the first year, after which time an adult-like first-winter plumage is acquired. It is very similar to adult female, but is somewhat paler on the upperparts, sometimes showing faint grey barring, and is variably tinged with buff on the face and underparts. The bill and feet are pinkish-buff in recently fledged juveniles, but these quickly turn grey. Juvenile females average slightly duller grey on the crown and nape and duller and more heavily tinged with buff on the upperparts and underparts than juvenile males.

Measurements
Total Length: 14.5-15 cm
Mass: 18.5-26.5 g

Source: Harrap and Quinn (1995); Grubb and Pravosudov (2008)


Biology

Identification

The structure, habits, and plumage characteristics of this species render it easy to identify under most circumstances.
Vocalizations

Voice is variable geographically. All subspecies have a similar song, given early in the breeding season (January-May), which consists of a series of soft, slightly nasal, whistled notes on one pitch: whi-whi-whi-whi-whi-whi-whi or hah-hah-hah-hah-hah-hah. Call notes vary between subspecies. Birds in northeastern B.C. and the central interior (S.c.carolinensis) give a characteristic low, nasal yenk or renk, often given as a slow series or slightly trilled. This call is reminiscent of the typical call of the Red-breasted Nuthatch. Birds of the southern interior (S.c.tenuissima) give a rapid yijijijijiji or yidi-yidi-yidi-yidi, with equal emphasis on all syllables. Birds of the Pacific coast subspecies (S.c.aculeata), which may occur as a vagrant on the south coast of B.C., give a high-pitched, drawn-out, yelping aaarn or beeerf that is distinctly longer, higher-pitched, and harsher than the call of the eastern carolinensis. All subspecies also give a variety of short, nasal yank and high, quiet ink contact notes throughout the year, with those of the Pacific coast aculeata averaging huskier than those of the eastern carolinensis.

Source: Harrap and Quinn (1995); Sibley (2000); Grubb and Pravosudov (2008)

Bird calls (and videos) from Cornell's Lab of Ornithology
Breeding Ecology

Courtship
This species is a monogamous breeder and maintains pair bonds throughout the year. Prior to breeding, the male engages in singing behaviour, plumage displays, courtship chases, and courtship feeding during the late winter in order to initiate mating.

Nest
Nest building begins in early spring (usually April), and nests are constructed solely by the female. This species is a cavity-nester, using natural cavities and abandoned woodpecker holes in both living and (more frequently) dead trees; although it may enlarge and augment existing holes, it does not excavate its own nest cavities. Nests are placed in cavities at heights ranging from 1.5-20 m, although mosts nests are placed 3-6 m above the ground. The nest hole is typically 3-4 cm or larger in diameter, with birds tending to prefer larger cavities when they are available. The depth of the nest cavity is variable, often exceeding 20 cm, and is terminated by a chamber that is lined with materials such as feathers, fur, wool, dirt clumps, dry grass, moss, bark strips, rootlets, and plant fibres. This species occasionally uses nest boxes, but less frequently than most other small cavity nesters.

Eggs
Clutches of (3) 5-7 (10) eggs are laid between mid-April and late May (primarily in early May). The incubation period is 12-14 days, and eggs are present in B.C. between mid-April and mid-June. Only the female incubates the eggs, although she is tended by the male during this period. The smooth, slightly glossy, white to creamy-white (rarely pinkish-white) eggs are speckled and spotted with light red, reddish-brown, and purplish-red (sometimes also paler grey and purplish). This species is rarely a victim of Brown-headed Cowbird parasitism elsewhere in its range, but this has not yet been documented in B.C. The White-breasted Nuthatch is typically single-brooded, but may replace clutches that are lost to predation.

Young
Young are present in B.C. between early May and mid-July, with most present between mid-May and mid-June. Both parents tend to the nestlings, which fledge and leave the nest at 18-26 days of age. Nestlings are altricial and downy, with pink skin, a cream-coloured mouth, and yellow gape flanges. After fledging, the young continue to be fed and tended to by both parents for another 2 weeks before becoming independent.

Source: Baicich and Harrison (1997); Campbell et al. (1997); Grubb and Pravosudov (2008)
Foraging Ecology

The White-breasted Nuthatch feeds on a variety of invertebrate prey and their larvae (including weevils, beetles, ants, scale insects, leafhoppers, and tent caterpillars) as well asplant matter such as acorns, seeds, and nuts. Seeds and nuts are most important as a food source in the winter and spring, and are rarely consumed during the summer. It usually forages singly or in pairs (rarely in groups of up to 6 individuals, especially in the late summer), and regularly joins mixed-species foraging flocks with chickadees and other nuthatch species. This species forages primarily on the trunk, limbs, and inner branches of trees, preferring larger (>7.5 cm diameter) limbs to smaller ones; sometimes forages in low shrubs or even briefly on the ground. Rarely engages in flycatching behaviour in pursuit of flying insects. During normal foraging activities, it intensively explores all branch surfaces, including the undersides, and often clings upside-down on trunks and vertical branches. Individuals secure food by exploring cracks in the bark as well as by excavating and exposing hidden food items from beneath the bark. It often wedges a piece of food into a crack in the bark for stability and subsequently hammers away at it with the bill to open it or tear it apart. It often stores or caches seeds and nuts for later consumption, usually concealing them in cracks or crevices in the bark of nearby trees. It commonly attends bird feeding stations.

Source: Harrap and Quinn (1995); Grubb and Pravosudov (2008)

Habitat


The habitats chosen by this species vary throughout its range in B.C. depending on geographic region and subspecies. Birds of northeastern B.C. (S.c.carolinensis), some of which winter in the central interior west of the Rocky Mountains, are almost entirely confined to deciduous woodlands throughout the year, particularly riparian cottonwood groves of and upland aspen stands; it sometimes occurs in mixed forests with some coniferous component (spruce, fir), but rarely (if ever) occurs in purely coniferous stands. Birds of the southern interior (S.c.tenuissima) are closely associated with dry coniferous (and sometimes mixed) forests, particularly stands of Ponderosa Pine and Douglas-fir. On the coast, vagrants are found in a variety of wooded habitats, including both deciduous and coniferous forests. In areas of human habitation, all subspecies (including vagrants) can be found in orchards and heavily treed suburban backyards, parks, and gardens.

Source: Harrap and Quinn (1995); Campbell et al. (1997)

Distribution

Global Range

Resident widely throughout eastern North America, from northeast B.C. east to Nova Scotia and south to eastern Texas and northern Florida. Also resident throughout western North America from southern B.C. south to southern Mexico (Oaxaca), occurring east to the Great Plains and west to the Pacific coast (north to Washington).
BC Distribution

Resident
Uncommon to fairly common at low to moderate elevations throughout the south-central and southeastern interior, from the Coast Mountains east to the southern Rocky Mountain Trench, ranging northwards to Williams Lake and Shuswap Lake in the south-central interior, and to Radium (rarely to Golden) along the Rocky Mountain Trench; in southern B.C., it is most abundant in the Okanagan and Thompson Basins and in the southern Rocky Mountain Trench and is scarce in the western Kootenays. Also uncommon (but increasing) in the Peace River lowlands of northeastern B.C. Casual confirmed and suspected extralimital breeding records have recently been documented across much of the central interior, from the Bulkley Valley east to the McBride and Quesnel areas, suggesting a sporadic presence across this region during the breeding season.

Non-breeding
Rare to very uncommon in winter (S.c.carolinensis) on the northern Fraser Plateau of the central interior, including the Mackenzie, Vanderhoof, Prince George, Quesnel, and McBride areas. There are several breeding-season records for this area, but nesting has not yet been confirmed.

Vagrancy
Very rare vagrant at all times of year on the south coast of B.C., primarily eastern and southern Vancouver Island and the Lower Mainland, with most records spanning the period from September to May. Accidental in fall in the Fort Nelson region of extreme northeastern B.C.

Source: Campbell et al. (1997)

Conservation

Population and Conservation Status

Populations of White-breasted Nuthatches in British Columbia are stable and secure, and subspecies carolinensis appears to be increasing in northeastern B.C. Similarly, the number of wintering birds (also carolinensis) in the central interior is also increasing, and the species is now recorded regularly (though infrequently) in this area, where it was formerly considered a vagrant. Increases in carolinensis in B.C. are mirrored by similar increases in adjacent areas of Alberta.

Source: Campbell et al. (1997)

Taxonomy


Seven subspecies of Sitta carolinensis are recognized, four of which occur in North America north of Mexico, with two or three ranging north into British Columbia. The subspecies fall into three fairly well-defined, geographically distinct subspecies groups based on vocalizations, habitat choice, and (to a lesser extent) plumage and structural differences. See ‘Vocalizations’ for notes on subspecific differences in voice, which are often the most reliable method of distinguishing among the subspecies. Representatives of two, and possibly all three, subspecies groups occur in British Columbia. Based on the differences between the groups, there has been some speculation that they may represent distinct species.

The subspecies that are known or suspected of occurring in B.C. are as follows:

Sitta carolinensis carolinensis
The sole member of the ‘Eastern’ subspecies group. This subspecies is resident across much of North America east of the Rocky Mountains, extending westwards as far as northeastern British Columbia (Peace River area). Small numbers of this subspecies also winter in the central interior of the province. S.c.carolinensis is distinguished from other subspecies by its relatively stout and blunt bill, paler blue-grey upperparts with more sharply contrasting black inner webs on the wing feathers, whiter underparts, and a somewhat broader black cap. The cap colouration of females is paler grey than in other subspecies, although some females can be relatively dark-capped. Westernmost populations, including those in B.C., average slightly larger and paler and have the lowest percentage of females with a blackish cap; these birds have sometimes been separated as subspecies ‘cookei,’ but this subspecies is no longer recognized. S.c.carolinensis is closely associated with deciduous woodlands throughout the year, particularly aspen and cottonwood stands.

Sitta carolinensis tenuissima Grinnell
One of four members of the ‘Great Basin’ subspecies group. This subspecies ranges throughout much of the Great Basin of the western U.S., extending northwards into the southern interior of B.C., occasionally wandering to the south coast of the province as a vagrant. It is similar to carolinensis, but has darker and less blue-toned upperparts with less distinct and contrasting dark inner webs on the wing feathers. As well, it has more extensive white on the face (narrower black cap), a relatively heavy grey wash on the flanks, and a longer and more slender bill. This subspecies is associated with dry coniferous forests, particularly Ponderosa Pine and Douglas-fir.

Sitta carolinensis aculeata Cassin
One of two members of the ‘Pacific coast’ subspecies group, this subspecies is found along the Pacific coast from Washington south to Baja California, although northernmost populations are nearly extirpated. Although not officially verified in the province, it is likely that at least some vagrants noted along the south coast of B.C. pertain to this subspecies. It is very similar to subspecies tenuissima, but is distinguished by the slightly buffy-tinged underparts with a less extensive grey wash on the flanks, slightly paler upperparts, and slightly shorter bill. This subspecies is associated with Douglas-fir and Garry Oak woodlands within its normal range, but may occur in a wider diversity of habitats as a vagrant.

Source: Harrap and Quinn (1995); Campbell et al. (1997); Sibley (2000); Grubb and Pravosudov (2008)

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)		COSEWIC
NativeS5YellowNot Listed



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