SPECIES

Northern Wheatear Oenanthe oenanthe Scientific name definitions

Erica H. Dunn, David J. T. Hussell, Josef Kren, and Amelia C. Zoerb
Version: 2.1 — Published October 25, 2022

Plumages, Molts, and Structure

Plumages

The Northern Wheatear has 10 functional primaries (numbered distally, p1 to p10, with the outermost primary, p10, reduced in length), 9 secondaries (numbered proximally, s1 to s9, and including 3 tertials, s7 to s9 in passerines), and 12 rectrices (numbered distally, r1 to r6, on each side of the tail). Geographic variation in appearance is moderate. The following molt and plumage descriptions pertain to the nominate Eurasian subspecies O. o. oenanthe, which also breeds in Alaska; see Systematics: Subspecies for variation in appearance in other subspecies.

See Molts for molt and plumage terminology. The following is based primarily on detailed plumage descriptions (12, 13, 2, 3, 14) and age-related criteria (15, 9, 16, 17). Sexes similar in juvenile and formative plumages but differ in alternate and definitive basic plumages. Definitive appearance is assumed at Second Basic Plumage.

Natal Down

Present primarily June–July. Natal down long, dense, and dark gray; primarily on upperparts (2).

Juvenile Plumage

Present primarily June–August. Similar to Definitive Basic Plumage, but upperpart feathers with paler buff or dirty cream centers and dark brown or black fringes, giving overall spotted appearance; rump and uppertail coverts with some black on feather tips; rectrix tips with rufous or grayish-white fringes; upperwing lesser and median coverts with whitish tips; greater coverts fringed rufous; auriculars mottled gray-brown and buff; throat, chest, breast, and flanks scalloped with narrow dark arcs. Juvenile body feathers (especially undertail coverts) filamentous due to lower barb density than feathers of later plumages.

Formative Plumage

In life-cycle terminology this is often referred to as Post-juvenile or First Non-breeding Plumage (see Molts). Present primarily September–March. Formative Plumage for both sexes similar to Definitive Basic female but most reliably distinguished by molt limits between worn juvenile and fresh formative feathers in upperwing (16, 17), and browner and more worn outer primaries and rectrices. Molt limits occur among the upperwing coverts, often between replaced median coverts and retained greater coverts, or in some cases 1–5 inner greater coverts replaced, darker rufous-brown to blackish brown, contrasting with more worn and paler brown to reddish-brown outer greater coverts; retained juvenile outer primary coverts, primaries, and rectrices narrower, more worn, and browner than in Definitive Basic Plumage. Examination of Macaulay images suggests occasional birds can also replace 1–2 tertials during the Preformative Molt. These criteria can be subtle and some individuals can be difficult to separate from Definitive Basic females based on plumage alone. Sexes similar in Formative Plumage; occasional males may be separable by more distinct black stripe on lores and blacker replaced formative wing coverts; and feathers replaced later (e.g., on nonbreeding grounds) may average blacker (auriculars) or grayer (head and scapulars). Look also for grayer bases to the formative head and back feathers of males than females.

First Alternate Plumage

In life-cycle terminology this is often referred to as the First Breeding Plumage (see Molts). Present primarily March–August. Similar to Definitive Alternate Plumages in each sex, but averaging duller.

Female. Similar to Definitive Alternate female; often indistinguishable by body plumage except upperparts often browner; black lore and eyeline faint or absent; pale supercilium averages less distinct.

Male. Males in First Alternate Plumage can be variable and dependent on extent of molts; body plumage can be similar to Definitive Alternate male but white on forehead more restricted and less distinct; black auriculars variably mottled olive brown; head and upperparts with some to extensive olive-brown on feather tips; back mostly to entirely olive-brown; sides of neck, throat, and chest deeper ocher buff, and less cream yellow. Duller individuals may resemble Definitive Alternate females.

In both sexes, criteria to separate First Alternate from Definitive Alternate Plumages similar to those described under Formative and Definitive Basic Plumages, with molt contrasts in wing and differences in condition of outer primaries and rectrices more pronounced due to accelerated rates of wear to juvenile feathers as compared with formative feathers. Limits between formative and juvenile median and greater coverts are still present despite occasional replacement of 1–3 inner greater coverts with broad cinnamon fringing during the First Prealternate Molt, these also being blacker-centered in First Alternate males than in females (16, 17). Age determination of males in spring relatively straightforward; ageing of females can be more difficult.

Definitive Basic Plumage

Present primarily September–February.

Female. Similar to Definitive Basic male but averages duller, less grayish; wings not as black. Crown and back uniform pale brown to olive-brown, often with slight but variable grayish tinge; sides of head with indistinct narrow supercilium, buff proximally, becoming cream white distally and wider above auriculars; rump and uppertail coverts white; tail as in Definitive Basic male. Lores dull black with variably extensive buff mottling; some buff specks often in front of and below eye, forming faint eye ring; auriculars darker brown, often washed gray, and finely streaked pale buff. Upperwing feathers as in Definitive Basic male, but browner basally and fringing to remiges paler cinnamon to whitish. Lower auriculars and sides of neck buffy cinnamon or pale rufous-brown, merging into slightly paler cinnamon-buff chin and deeper cinnamon sides of throat, lower throat, and sides of breast; flanks and lower underparts pink-buff to cream-buff, becoming whiter on central belly; underwing coverts as in Definitive Basic male but duller and less contrasting. In December–March, crown and back can become slightly grayer and auriculars slightly blacker through feather wear.

Male. Forehead and supercilium white, contrasting indistinctly with olive-brown crown; forecrown through back feathers silvery gray basally but broadly tipped with olive or rusty brown, largely concealing gray appearance; rump and uppertail coverts white; tail distinctly patterned, the central rectrices (r1) extensively black and the remaining rectrices (r2–r6) with distal portions black and proximal portions white, forming inverted-T appearance, the feathers thinly fringed and tipped with off-white (1–2 mm wide) when fresh; amount of black on the rectrices varies individually. Lores and widening patch in front of eye deep black; auriculars black with variable brownish fringing when fresh, which becomes more extensive distally, concealing black mask. Upperwing feathers sooty blackish, the lesser and median coverts sometimes with traces of pale gray, the greater coverts broadly fringed olive-brown and tipped paler brown, and the primary coverts, primaries, secondaries, and tertials black with narrow pale olive-brown to rufous-gray fringes when fresh. Chin and subauricular area pale cinnamon to white; throat, chest, and sides of breast deep buffy cinnamon; remainder of underparts pale cinnamon to creamy buff, becoming paler on central belly; undertail coverts white washed cream or cinnamon; underwing coverts and axillaries white with large black feather centers. In December–March, crown and back become increasingly grayish and auriculars increasingly black through feather wear.

In both sexes, Definitive Basic Plumage separated from Formative Plumage by having wing and tail feathers uniform in quality and freshness: upperwing median and greater coverts uniform in quality, without molt limits; basic primary coverts, outer primaries, and rectrices broader, more truncate, and relatively fresher, dusky to dark brown in females and black in males; age determination of females can be difficult.

Definitive Alternate Plumage

Present primarily March–August.

Female. Similar to Definitive Basic female but plumage slightly grayer (crown and back), duskier (auriculars), and whiter (underparts) due to combination of feather wear and some limited body and or wing feather molt. Forehead and indistinct supercilium whitish; crown, hindneck, mantle, scapulars, and back variably brownish gray to dull pale gray; feathering from nostrils through lores to upper auriculars dark brown, forming indistinct dark mask (thinner than in male); upperwing more uniformly brown due to wearing of feather fringes, 1–3 inner greater coverts sometimes replaced and similar in color but fresher and with paler brownish fringing; lower auriculars, subauricular area, and chin variably white or slightly tinged creamy white; sides of neck, throat, chest, and sides of breast variably dull cinnamon to cream buff; remainder of underparts white or with slight cream tinge.

Male. Similar to Definitive Basic male but plumage distinctly grayer (crown and back), blacker (auriculars), and whiter (underparts) due to combination of feather wear (see below) and some limited molt. Forehead and broad supercilium white; crown, hindneck, mantle, scapulars, and back light gray to silvery gray; feathering from nostrils through lores to upper auriculars black, forming prominent black mask; upperwing blacker, often uniformly slate due to wearing of feather fringes, 1–3 inner greater coverts sometimes replaced and similar in color but fresher and with broad cinnamon fringing as in fresher basic feathers; subauricular area and chin variably white or slightly tinged creamy white; sides of neck, throat, chest, and sides of breast variably cinnamon to cream buff or yellow buff; breast, flanks, and undertail coverts white or with slight cream tinge; lower central belly and undertail coverts white. Differences from Definitive Basic Plumage primarily due to wearing of brown fringes from body and wing feathers, which shortens feathers by up to a third; resultant dramatic change sometimes assumed erroneously to result from extensive Definitive Prealternate Molt (18).

See First Alternate Plumage for criteria separating it from Definitive Alternate Plumage.

Aberrant Plumages

Partial or wholly leucistic individuals reported occasionally (4). A true albino was photographed both as a nestling and as an independent juvenile (19).

Molts

General

Molt and plumage terminology follow Humphrey and Parkes ( 20), as modified by Howell et al. (21). Under this nomenclature, terminology is based on evolution of molts along ancestral lineages of birds from ecdysis (molts) of reptiles, rather than on molts relative to breeding season, location, or time of the year, the latter generally referred to as “life-cycle” molt terminology (16). In north-temperate latitudes and among passerines, the Humphrey-Parkes (H-P) and life-cycle nomenclatures correspond to some extent but terms are not synonyms due to the differing bases of definition. Prebasic molts often correspond to “post-breeding“ or “post-nuptial“ molts, preformative molts often correspond to “post-juvenile“ molts, and prealternate molts often correspond with “pre-breeding“ molts of life-cycle terminology. However, for species that suspend prebasic or preformative molts for migration or undergo extensive molts on winter grounds, there is often a lack of correspondence between H-P and life-cycle terms (22). The terms prejuvenile molt and juvenile plumage are preserved under H-P terminology (considered synonyms of first prebasic molt and first basic plumage, respectively) and the former terms do correspond with those in life-cycle terminology.

Northern Wheatear exhibits a Complex Alternate Strategy (cf. 21, 23), including complete prebasic molts, a partial preformative molt, and limited-to-partial prealternate molts in both first and definitive cycles (12, 24, 2 , 15, 25, 9, 16, 17; Figure 1).

Prejuvenile Molt

Complete, May–July, in the nest. Near-complete by fledging at 14–17 d, except that flight feathers still only about half grown (DJTH, see Breeding: Young Birds).

Preformative Molt

"First Prebasic" or "Prebasic I" molt of Humphrey and Parkes (20) and later authors; see revision by Howell et al. (21). Preformative ("Post-juvenile") Molt partial, primarily June–October, commencing and often completing on or near breeding grounds, but sometimes completing on winter grounds (2), and perhaps extending into mid-winter (where sometimes considered part of the first pre-breeding molt of life-cycle terminology). Typically occurs at age 5–8 weeks of age. Includes most or all body feathers and upperwing lesser and median coverts, sometimes (in ~30% of individuals) 1–5 inner greater coverts, and perhaps occasionally one or more tertials (16); however, reported tertial replacement may have resulted from accidentally replaced feathers. Earlier-fledged individuals molt more feathers on average than later-fledged birds (2).

Juvenile O. o. leucorhoa on Baffin Island start molting lesser and median coverts about mid-July; complete in most birds by late August (n = 68; DJTH). Greater coverts molted by only 3% of sample, and no birds replaced tertials. Early stage of body molt marked by appearance of cinnamon on flanks. Body feathers grow more slowly than coverts and are still growing on many birds in early September, although no external sign of juvenile plumage visible once new feathers are more than 2/3 grown (DJTH).

First Prealternate and Definitive Prealternate Molts

Often corresponds to "First Pre-breeding" and "Adult Pre-breeding" molts of life-cycle terminology. Limited to partial, primarily February–April, on non-breeding grounds; reports of this molt commencing as early as December (2) may refer to protracted and suspended preformative or prebasic molts; study is needed on molts away from breeding grounds. Includes a few to many head feathers and none to a few on body, occasionally a few upperwing lesser and median coverts and sometimes (in ~20% of individuals) up to 3 inner greater coverts (16). Molt of body feathers often suppressed, though a substantial change in appearance results from extensive wear of brown feather tips; 18). First and Definitive Prealternate Molts similar in timing and extent, as far as known; reports that the First Prealternate Molt can be more extensive and can include 1–2 tertials is probably based on replacement of these feathers during suspended Preformative Molt on non-breeding grounds (2).

Definitive Prebasic Molt

Often corresponds to "Adult Post-breeding Molt" of life-cycle terminology. Complete, primarily July–September, on or near breeding grounds, although occasionally molt can be completed after start of southbound migration or on winter grounds (2), perhaps into mid winter (where sometimes considered part of the adult pre-breeding molt of life-cycle terminology). Primaries (and corresponding primary coverts) are replaced distally (p1 to p10), secondaries are replaced proximally from s1 and, likely, proximally and distally from the central or innermost tertial (s8 or s9) as typical of passerines, and rectrices are replaced rapidly and distally (r1 to r6) on each side of tail, with some variation in sequence possible. Molt of primaries completed in 40–50 d, tail molt in 21–28 d (2).

Molt coincides with post-breeding period, usually after > 90% of young have become independent (26, DJTH) (see Breeding: Immature Stage for timing). Females molt flight feathers slightly later than males, and adults with late broods begin later than other adults (up to 6 days in males and 23 in females), such that female molt frequently overlaps with feeding of young (27). In the rare cases of leucorhoa double-brooding in eastern Canada, males also overlap molt with feeding of young, though still in advance of females (28, Figure 2).

Bare Parts

Bill and Gape

Bill straight, slightly decurved on tip of culmen, rather deep and wide at base; nostril oval (2). In nestlings, bill brownish, cere lemon yellow, gape and inside of mouth bright orange-yellow or, at least in some leucorhoa, ‘dirty yellow’ (29). Bill of juvenile is dark brown, dark pinkish brown, or grayish black, and inside of mouth and upper mandible mixed grayish and yellow, at least some yellow remaining through first fall (15). Adult bill grayish black to black; inside of upper mandible gray black.

Iris and Facial Skin

Iris in adults and juveniles is dark brown (2) or hazel (29).

Tarsi and Toes

In juveniles, legs and feet dark brown, dark pinkish brown, or grayish black; in adults, grayish black or black. (2).

Measurements

Linear Measurements

There is considerable variation in size and shape across the global range (details in Appendix 1). Measurements of yearling male oenanthe breeding in Sweden illustrate general size (in mm; D. Arlt, personal communication): wing chord (straightened and flattened) = 97.1 ± 1.9 (range 92–102, n = 356), tail length = 54.2 ± 1.8 (range 49–61, n = 342), bill length (tip to skull) = 18.2 ± 0.8 (range 15.9–21.5, n = 279). Tarsus length of yearling male oenanthe breeding in Alaska averaged 27.5 ± 0.78 mm (range 26.1–29.9, n = 74; H. Schmaljohann, personal communication).

Males are larger than females (Appendix 1), with wing and tail measurements differing significantly between sexes in all 4 subspecies (2). In oenanthe, old males are significantly larger than young males (30).

O. o. libanotica is about the same size as oenanthe, though differing in wing and tail shape. Leucorhoa are larger than oenanthe and are usually separated by the wing length criteria of Svensson (15): leucorhoa if > 97 mm (females) or > 102 mm (males); oenanthe if wing length < 96 mm (females) or < 99 mm (males). However, ranges and in some cases SD of wing lengths overlap (Appendix 1), so some individuals will be misclassified, especially breeders from Alaska and other northern regions. For example, 6% of oenanthe females breeding in Sweden met the criteria for leucorhoa (n = 700; D. Arlt, personal communication).

Wing Area, Wing Aspect Ratio, Wing Loading

Relative wing length and wing shape vary significantly with length of migratory distance (31). Within oenanthe, birds from the far northeastern parts of the range have relatively longer, broader and more pointed wings and more forked tails than individuals in western Europe, whereas samples of oenanthe and libanotica travelling intermediate distances have intermediate flight apparatus. All leucorhoa have the wing and tail characteristics of long-distance migrants. Wing shape index does not appear to increase once migratory distance exceeds about 5,000 km (31), and essentially all leucorhoa migrate farther than that.

Within leucorhoa, but not oenanthe, wings are more pointed in males (32).

Mass

Average mass of yearling male oenanthe in Sweden = 22.8 ± 1.2 gm (range 20.0–25.5, n = 332 (D. Arlt, personal communication). Adult male leucorhoa are heavier: 28.5 ± 1.61 gm (range 23.8–32.2, n = 88; DJTH). In the three subspecies for which there are data, mass of females is similar to that of males (Appendix 1).

Female oenanthe gain mass prior to laying and lose close to 15% of mass in the week after nestlings hatch, whereas male mass is relatively constant throughout the breeding period (33). For changes in mass during the nonbreeding period, see Movements and Migration: Control and Physiology of Migration.

Recommended Citation

Dunn, E. H., D. J. T. Hussell, J. Kren, and A. C. Zoerb (2022). Northern Wheatear (Oenanthe oenanthe), version 2.1. In Birds of the World (P. G. Rodewald and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.norwhe.02.1