HBW 13 - Species accounts: White-breasted Nuthatch (Sitta carolinensis)

19. White-breasted Nuthatch
Sitta carolinensis
French: Sittelle à poitrine blanche   German: Carolinakleiber   Spanish: Trepador Pechiblanco

Other common names : White-breasted Black-capped/White-breasted American/Carolina/Common Nuthatch; Florida Nuthatch (carolinensis); Rocky Mountain Nuthatch (nelsoni); Inyo Nuthatch (tenuissima)

Taxonomy. Sitta carolinensis Latham, 1790, in America, Jamaica = South Carolina, USA.
Relationships uncertain. Bears a superficial resemblance to S. leucopsis and S. przewalskii and sometimes placed in the superspecies formed by those two, although some authors doubt such a close relationship. Recent studies of mitochondrial DNA, while not addressing this problem, suggest that present species is close to S. himalayensis and S. europaea. Geographical variation relatively slight and largely clinal, upperparts (and, to lesser extent, underparts) on average darkest in Rocky Mts and Mexico, becoming paler towards W and especially E coasts; race alexandrae sometimes merged with tenuissima, and oberholseri with nelsoni; population in NE of range (E Canada and NE USA) sometimes separated as race cookei, with slightly paler back, and with most females pale-capped, but differences from nominate clinal and/or not constant. Proposed race atkinsi from SE USA (Tarpon Springs, in Florida) synonymized with nominate, and N Mexican umbrosa (from Sierra Madre near Guadalupe y Calvo, in SW Chihuahua) with mexicana. Nine subspecies recognized.
Subspecies and Distribution
. S. c. tenuissima Grinnell, 1918 – SW Canada (S British Columbia S from Lillooet), and W USA in Cascades of E Washington and Oregon, W Montana, W Wyoming, Idaho, C & W Nevada, and E California (generally E of Sierra Nevada, S to Inyo County).
S. c. aculeata Cassin, 1856 – W Washington, W Oregon and W California (Pacific lowlands W of Cascades, and crest of Sierra Nevada and mountains in S), and extreme NW Mexico (Sierra de Juárez, in extreme N Baja California).
S. c. alexandrae Grinnell, 1926 – N Baja California Norte (Sierra San Pedro Mártir).
S. c. lagunae Brewster, 1891 – extreme S Baja California (Sierra de San Lázaro).
S. c. nelsoni Mearns, 1902 – Rocky Mts from N Montana S to E Nevada, Utah, Wyoming, W Colorado, Arizona (except SW deserts), W New Mexico, extreme W Oklahoma and W Texas (Davis and Guadalupe mountains), and N Mexico (NE Sonora and extreme NW Chihuahua).
S. c. carolinensis Latham, 1790 – C & E Canada from C & S Alberta (S from Lesser Slave L), SE Saskatchewan (S & E from Prince Albert), S Manitoba (S from R Swan and Winnipeg) and extreme SW & SE Ontario E to New Brunswick and Nova Scotia (including Prince Edward I and Cape Breton I), and S in USA to Gulf Coast and C Florida (E from North Dakota, South Dakota, Nebraska, Kansas, Oklahoma and E Texas).
S. c. oberholseri H. W. Brandt, 1938 – SW Texas (Chisos Mts) and NE Mexico (N Sierra Madre Oriental S to W Nuevo León and, probably, interior SW Tamaulipas.
S. c. mexicana Nelson & Palmer, 1894 – W, C & S Mexico in Sierra Madre Occidental and associated ranges from SE Sonora and C Chihuahua S to Jalisco Michoacán, Hidalgo, Puebla, and WC Veracruz (Jalapa, Mt Citlaltepetl), and S Sierra Madre Oriental from C Nuevo León (Gulf slope) and SE Coahuila S to SW Tamaulipas and E San Luis Potosí.
S. c. kinneari van Rossem, 1939 – S Mexico in Guerrero and Oaxaca (Sierra Madre del Sur).
Descriptive notes . 15·5 cm; 19·6–22·9 g. A medium-large nuthatch with white face and underparts, and straight or slightly upturned long bill. Male nominate race in fresh plumage (about Aug–Mar) has crown, nape and upper mantle black, faintly glossed greenish-blue, the black narrowing at side of upper mantle, remainder of upperparts light grey, tinged blue; upperwing-coverts blackish-grey, fringed and tipped light grey, greater coverts variably tipped whiter (especially on inner feathers), alula blackish, fringed white, primary coverts blackish, narrowly fringed pale grey; inner web of inner two tertials blackish, outer webs and streak along shaft of inner web of central tertial pale grey, inner web of outermost tertial pale grey, fringed blackish on distal half (more broadly so at tip), outer web blackish, fringed and very broadly tipped pale grey; secondaries blackish-grey, fringed and narrowly tipped pale grey, primaries sooty black, inner primaries narrowly fringed grey-white and with broader pale grey tip, P3–P6 with broad white fringe around emargination and pale grey tip; central tail feathers light bluish-grey (as upperparts), other rectrices black, T2 and T3 narrowly tipped light grey and with small whitish spot at tip of shaft, outer three feather pairs with broad white subterminal diagonal band (extending to base of outer web on T6, to tip of inner web on T4); lores, supercilium, side of head and underparts whitish (sometimes very faint dark barring on side of neck), often with very thin postocular black stripe, lower breast and belly faintly tinged buff, vent warmer buff, rear flanks pale grey, undertail-coverts pale grey with broad white triangular tips and broadly fringed orange-rufous at base, thighs pale grey with orange-rufous tips; axillaries whitish, underwing-coverts sooty black, longer under primary coverts and base of primaries white; in worn plumage, underparts slightly duller; iris dark brown; bill grey-black or black, basal two-thirds of lower mandible paler and greyer, cutting edges off-white; legs dark brown or dark grey-brown, claws blackish. Female differs slightly from male, in fresh plumage has duller cap varying from dull black to light grey (on average, palest in NE USA, and with many intermediates, some not reliably distinguishable from male in field), narrower blackish band on border of upper mantle, paler and duller grey upperparts (variably tinged brown), brownish or greenish wash on fringes of wing feathers, duller face and underparts variably washed buff. Juvenile is similar to adult but a little paler and duller, male has cap dull black (resembling that of many adult females in coloration), secondary fringes washed orange-buff, underparts washed buff (coloration close to that of worn adult), juvenile female separated from young male by duller cap and more extensive drab wash on wing-feather fringes. Races vary mainly in plumage tone (darkness or lightness), also in size and bill size: nelsoni male has cap with more distinct and greener gloss, darker (dark grey) upperparts with more distinct blue tone, reduced contrast in wing (darker feather centres duller and slightly browner, fringes darker grey), tertials finely fringed rufous, central tertial with more black at base of outer web, longest with more black at base of inner web, underparts cleaner and whiter, flanks and belly more extensively light grey, vent tinged buff, female cap often nearly as dark as that of male (but not so clean and glossy, and contrasting less with mantle), has variable rufous-brown tone on mantle, perhaps slightly less buff on underparts than nominate female; tenuissima is poorly differentiated, as previous but upperparts fractionally paler (still significantly darker than nominate), also smaller, but bill rather more slender and sharply pointed; aculeata is as last, but on average slightly paler above (but distinctly darker than nominate), upperparts of female slightly more olive-brown, male on average slightly buffer, less grey-toned, below (female slightly buffier), vent darker and more cinnamon-brown, also smaller and with bill shorter, weak and more slender; alexandrae resembles last, but upperparts marginally darker, also larger, with bill longest of all races; lagunae is as preceding race, but upperparts slightly darker, male underparts darker and with increased buff wash, upper flanks medium grey, rear flanks more cinnamon-rufous, is also smaller, with bill relatively stout (but more slender than that of other Mexican races); oberholseri is poorly differentiated, resembles nelsoni but upperparts (especially of female) slightly darker, underparts slightly darker and greyer (rear flanks and vent of female especially so); mexicana is as previous, but upperparts marginally duller, female with more intense olive-brown wash and with fringes of greater coverts and flight-feathers variably (usually strongly) tinged rusty-buff, underparts rather duller and sullied buff (less grey), male flanks darker and duller grey, female with drab pinkish extending to belly, also bill shorter and relatively stout; kinneari is smallest race, resembles last, but female underparts on average slightly more orange-buff, this colour extending to breast and throat, bill short and stout. Voice. Contact call, given all year but especially in autumn and winter, a soft, thin, relatively high-pitched and slightly squeaky “nit” or “hit”, varying in tone and emphasis, sometimes repeated at rate of 30 per minute, or combined/alternated with louder and more emphatic “chuck” or “tuk” as conversational “ hit-tuk, hit-tuk”; also single “tchup” in mild excitement. Perhaps most characteristic call a rather nasal “kri”, often rendered as “kun”, “ka-un” or “quank”, variations indicating level of excitement, e.g. single shrill and rather nasal “kri” or “qui” (“quank”) in mild excitement, irregular shrill “kri, kri kri…” or “qui-qui-qui…” series in heightened excitement, and a repetition of two “kri” calls in quick succession, “kri-kri, kri-kri”, in even greater agitation; significant agitation or excitement indicated also by rapid series of 4–8 (4–21) “kri”-type notes (up to 8–10 per second), at varying pitches, on average higher-pitched and often in rapid series in Great Basin and Rocky Mts (race tenuissima); alternatively, may emit slower and quieter series of conversational, nasal “ krit, krit, krit-krit, krit…” notes; all of these “kri” (or “quank”) calls sometimes given in rather harsher and even more nasal form (notes characterized by rapid frequency modulation), in couplets or long series at varying speed, from strident “krrr-krrr, krrr-krrr” couplets to “ krr-krr-krr” triplets and to longer series, also chattering “krrr’krr’krrr’krr” phrases. Other calls include low, harsh, trilling “brr-aa” during aggressive encounters, long, high-pitched quiet “ phee-oo” whistle (rising and then falling) by male during display-flight and by female when soliciting copulation, and high “chrr” or “k’duck, k’duck” notes by female during courtship feeding (also by begging nestlings). Song, Jan–May in NE USA, by male from top of tall tree, most regularly shortly after dawn, in two forms: “slow” song a rapid series of 6–11 nasal and quite high-pitched “ que” or “hah” notes (similar to “quank” note but higher, thinner and less nasal), c. 6 per second, “ qui-qui-qui-qui-qui-qui”, each note slightly inflected, series often starting relatively quietly but quickly building in volume (variants include phrases of more clearly upward-inflected notes, “ tui-tui-tui-tui-tui”); “fast” song given in heightened excitement, c. 10–12 notes per second, rather similar to the more rapid series of “kri” notes but on average faster.
Habitat . In E parts of range, primarily mature open deciduous forest, also mixed forest, e.g. maple–hemlock–pine (AcerTsugaPinus) in N, also orchards, woodlots, shade trees, parks, gardens and cemeteries in suburban areas, but generally absent from spruce–fir (PiceaAbies) forests (e.g. the Adirondacks, in New York) and from boreal forests of N; absent also from bottomlands in Arkansas, but in SE USA does breed in pine and oak–pine (QuercusPinus) forests; penetrates Great Plains in riparian woodland and scattered stands of ponderosa pine (Pinus ponderosa). In W of range, open montane pine forest, also Douglas fir (Pseudotsuga) in W Washington, and in pinyon–juniper (PinusJuniperus), aspen (Populus) and, in Pacific lowlands, pine–oak and evergreen oak. In Mexico, found in montane pine–oak, and in N Baja California also pine forests. Throughout range an essential requirement is mature or rotten trees with holes suitable for nesting, and in E the presence of oak, beech (Fagus) and hickory (Carya) and their fruits may be important; favours clearings and other edge habitats. Generally lowlands in E, but to 1675 m in Tennessee; in W largely montane, and occurs at up to 2590 m in Idaho, 3200 m in Nevada, 2600 m in Arizona, at 2135–2440 m in New Mexico (dispersing to both higher and lower elevations, 3050 m and 1525 m, and also in riparian woodlands in Santa Cruz valley), up to 2590 m in SW Texas (Davis Mts), and in California breeding to 3230 m (dispersing as high as 3350 m in late summer) and in Yosemite National Park (E California) common below 915 m (probably race aculeata), scarce at 915–2440 m but more numerous again above 2440 m (probably tenuissima), and often remains in winter up to at least 2600 m. In Mexico, recorded at 1830–2600 m N Baja California (Sierra San Pedro Mártir), 1585–1950 m in Sinaloa, 1525–3050 m in Chihuahua, 1980–2440 m in N Coahuila (Sierra del Carmen), at 2440 m in Durango, 915 m in Nayarit and 3350 m in México, and from 1890 m to at least 2745 m in Oaxaca.
Food and Feeding . Food in summer largely insects and spiders (Araneae), and young may be fed entirely with animal items; in autumn and winter largely vegetarian, with diet of nuts, seeds and berries; visits garden feeders for suet, and occasionally feeds on tree sap. Males always dominant over females at food. Not very gregarious, and usually found singly or in pairs; in late summer (and sometimes through winter) also in family parties, and will join mixed-species flocks as these pass through territory. Forages on trunk and larger branches of trees, also among thinner outer twigs, in shrubs and occasionally in leaf litter on ground. Gleans from bark, and has been recorded as using a bark flake to pry off other pieces of bark; searches litter for fallen mast; sometimes takes aerial insects by flycatching. Stores large quantities of food, dispersing single items throughout territory in such places as bark crevices in trunks and larger branches of trees (occasionally covers these with bark flakes or lichen), also around habitations in cracks in poles, under loose shingles and similar sites; in spring stores food both inside and immediately outside nest-hole, and may cache such items as sugar maple (Acer saccharum) buds and soil pellets (which are not eaten). Removes some items from feeders and caches these nearby.
Breeding . Season usually rather early, e.g. from late Apr in Canada (Ontario), and in USA mid-Apr to May in N & E (North Dakota, New York and Ohio), late Mar to Jun in W (California) and, in S, late Feb to Mar in Oklahoma and late Mar to Apr in Texas; Mar in S Mexico (Oaxaca); single-brooded. Apparently pairs for life, and pair-bond maintained from year to year, being renewed in late winter, but partners may not be together all the time (male more wide-ranging, especially in winter, contact maintained vocally). Singing male stretches vertically upwards and bows with each note (also occasionally sings in flight). Nest built by female, materials supplied by male, a foundation of wood chips, bark strips, small pellets of earth and mud, twigs, grass, leaves and fur (used as necessary to fill cavity), lined with fur, hair, wool and feathers, placed usually in natural hole 0·5–21 m (mostly 3–12 m) above ground in dead deciduous tree or decaying stump, often rotted-out knothole, less frequently abandoned woodpecker (Picidae) excavation, nestbox or even space under eave of house used, hole with entrance 30–40 mm in diameter preferred and may enlarge entrance of existing cavity; site selected by female, which may even usurp a male from his roost-hole in early spring and take over this cavity for nesting. Clutch 3–10 eggs (usually 5–9), white, sometimes tinged pink, spotted reddish-brown, spots often concentrated at larger end with some lavender markings, mean size 19·3 × 14·5 mm; replacement clutch laid if original lost; incubation by female, fed on and off nest by male, period 12–15 days; nestlings fed by both parents, largely by male in first few days after hatching, female spending much time in brooding young; chicks fledge after 18–26 days, continue to be fed by adults for a further 14 days. Female, usually while holding insects (sometimes fur or plant material, or nothing) in bill, engages in bill-sweeping display both in and outside nest-hole, especially around protuberances and branch junctions, possibly as a means of repelling predators or nest-hole competitors.
Movements . Generally sedentary; some retreat from extreme N parts of range and from high altitudes (notably in W) in winter, some individuals returning to same wintering territory in successive years, also some irregular and localized dispersal in spring and autumn. Movements usually over short distance, but found away from breeding areas in Great Plains and in deserts of SW, in riverine forests, on isolated wooded desert massifs, and in suburban parks and gardens; frequent in lower Sonoran zone of Arizona, but scarce or rather rare Aug–Apr visitor in areas outside breeding range in Florida, Texas (not S) and California. Commoner in some years than in others away from breeding areas, but no indication of any irregular large-scale irruptions. Vagrant in Canada to Vancouver I (British Columbia) and Sable I (Nova Scotia), in SW USA on Californian islands, and also in W Atlantic (Bermuda); in Oct 1963, one came aboard an ocean liner sailing W (6 hours out of New York).
Status and Conservation . Not globally threatened. Fairly common in much of range; uncommon to rare on edges of range. Commonest in NE USA and in some areas along R Mississippi; relatively uncommon in much of Canada and Mid West, and scarce or rare on extreme N perimeter of range and local in much of Great Plains, Great Basin and S. Recorded breeding densities vary from 4·9 pairs/10 ha (West Virginia) to 0·2 pairs/10 ha (Colorado). In Mexico, common in SW Jalisco (Volcanes de Colima) and N Coahuila (Sierra del Carmen), and fairly common in Baja California; uncommon in Sonora and Oaxaca. Thought to have decreased in early 20th century throughout SE USA, from Texas E to Florida (and currently considered close to extinction in peninsular Florida). Conversely, may be extending range in N Great Plains and into SE Washington, and recent increase in Alberta (Canada); in NE USA distribution has expanded since early 1900s along with regrowth of forests.
Bibliography. Aldrich (1944), Bent (1948), Durand (1972), Duyck et al. (1991), Godfrey (1986), Harrap & Quinn (1996), Hawbecker (1948), Kilham (1968, 1971, 1972), Matthysen (1998), Oberholser (1974), Pasquet (1998), Phillips (1986), Pravosudov & Grubb (1993), Ritchison (1981, 1983), Spellman & Klicka (2007), Wood (1992).