Plumages, Molts, and Structure

Black-and-white Warblers have 9 functional primaries, 9 secondaries (including 3 tertials), and 12 rectrices. Little or no geographic variation in appearance (see Systematics: Geographic Variation) or geographic or sex-specific variation in molt strategies reported; southern populations may commence molts earlier based on earlier breeding seasons.

Following based primarily on detailed plumage descriptions of Dwight (Dwight 1900c Dwight, J., Jr. (1900). The sequence of plumages and moults of the passerine birds of New York. Annals of the New York Academy of Sciences 13:73–360. Close ), Ridgway (1902), Oberholser (1974), Curson et al. (Curson et al. 1994 Curson, J., D. Quinn, and D. Beadle (1994). Warblers of the Americas: an Identification Guide. Houghton Mifflin Company, New York, NY, USA. Close ), and Dunn and Garrett (1997), as modified by K. Parkes (pers. comm.); see Robbins (1964) and Pyle (1997a) for specific age-and sex-related criteria. Appearances of sexes similar in Juvenile Plumage but differ in subsequent plumages; Definitive Plumages assumed at Second Basic and Second Alternate plumages.

Natal Down

Present primarily May–Jun, in the nest. Down very dark gray; on head, lower back, wings, and thighs.

Juvenile (First Basic) Plumage

Present primarily May–Jul. Juvenile Plumage ephemeral and variation not well described; see illustration in Curson et al. (Curson et al. 1994 Curson, J., D. Quinn, and D. Beadle (1994). Warblers of the Americas: an Identification Guide. Houghton Mifflin Company, New York, NY, USA. Close : Plate 16). Upperparts wood-brown, streaked dull olive-brown, with buff median crown and superciliary stripes; uppertail coverts dusky. Wings and tail primarily dull black with feathers edged ashy gray; tertials grade from black to blackish distally, broadly edged with white, that of the central tertial (s8) tinged buff; upperwing median and greater coverts tipped buff, forming 2 wing-bars; outer 2 rectrices with terminal white patches of variable extent on the inner webs more extensive and distinct in males than females (see Formative and Definitive Basic plumages). Underparts dull white, the throat and sides washed wood-brown, the throat, breast, and undertail coverts spotted grayish black, and the flanks obscurely streaked dull grayish black. Except for outer rectrices, sexes alike in plumage.

Formative Plumage

"First Basic" or "Basic I" plumage of Humphrey and Parkes (1959) and later authors; see revision by Howell et al. (2003). Present primarily Sep–Mar.

Male. Similar to Definitive Basic female but black ventral streaking more distinct (veiled white when fresh); chin, throat, breast, and abdomen unmarked.

Female. Similar to Definitive Basic female but duller (especially ventral streaking); white areas of upperparts, including crown stripe, variably washed buff; outer rectrices (r5–r6) with smaller and less-distinct white patches; streaks of sides and flanks dull black to pale gray and indistinct, never as broad as in males. In both sexes Formative Plumage further distinguished from Definitive Basic Plumage by molt limits between replaced formative upperwing greater coverts, and contrastingly older and browner retained juvenile primary coverts; retained juvenile outer primaries and rectrices thinner, more pointed, browner, and relatively more worn, the latter averaging smaller and less-distinct white patches to r5-r6, sex for sex (Pyle 1997a). Beware tertials intrinsically contain more melanin, creating "pseudolimits" or false appearance of molt limits in both Formative and Definitive Basic plumages (Pyle 1997a).

First Alternate Plumage

Present primarily Mar–Aug.

Male. Similar to Definitive Alternate male but blackish portions of head duller; lower throat often faintly mottled whitish; outer rectrices (r5-r6) with smaller and less-distinct white patches.

Female. Similar to Formative female but whitish areas of auriculars and underparts whiter (less buff). Criteria to separate First Alternate from Definitive Alternate plumages similar to that described under Formative and Definitive Basic plumages (1–3 tertials usually replaced in both age groups, contrastingly fresher and blacker), the molt contrast in the upperwing coverts often becoming more pronounced due to increased degradation rate of retained juvenile feathers compared with replaced formative feathers.

Definitive Basic Plumage

Present primarily Sep–Mar.

Male. Crown black with broad white median and superciliary stripes extending to nape; lores, auriculars, chin, and throat black mottled with whitish feather fringing when fresh; white eye-ring contrasts with black auriculars below; auriculars separated from chin and throat by broad white subauricular stripe. Upperparts and sides of neck streaked black and white. Wings black with narrow whitish feather edges (broadest and whitest on tertials); upperwing greater and median coverts tipped white, forming 2 bold wing-bars. Rectrices dull black with gray edgings broadest on both webs of central pair (r1), progressively narrower and restricted to outer web on r2–r6; outer two rectrices with distinct and large white spots on each side of tail, the outermost (r6) with terminal third or more of inner web (only) white and the adjacent rectrix (r5) with similar but smaller white area. Breast, flanks, lower underparts, and undertial coverts white with bold, black streaks.

Female. Similar to Definitive Basic male but duller and with much less black in head; lores and auriculars whitish to pale gray; chin and throat white or tinged pale buff when fresh; streaking to sides of neck and underparts grayish black and less extensive (more confined to flanks); flanks tinged pale buff when fresh; spots on outer rectrices (r5–r6) marginally smaller than in male.

In both sexes Definitive Basic Plumage separated from Formative Plumage by having wing and tail feathers uniform in quality and freshness, the primary coverts duskier (with little or no brown tinge) and not contrasting in feather quality with blacker greater coverts; basic outer primaries and rectrices broader, more truncate, duskier, relatively fresher, and averaging larger white spots to r5-r6, sex for sex (Pyle 1997a). Beware of "pseudolimits" among the tertials (see Formative Plumage).

Definitive Alternate Plumage

Present primarily Mar–Aug.

Male. Similar to Definitive Basic male but plumage blacker and bolder due to combination of molt and wearing of pale feather fringing. Lores, auriculars, chin, and throat blacker and without pale mottling, separated more sharply by narrower white subauricular stripe; black streaking to underparts and undertail coverts bolder and more distinct.

Female. Similar to Definitive Basic female but plumage slightly bolder; throat and flanks whiter, without buff tinge. See above for criteria to separate First from Definitive Alternate plumages.

In a study of 29 individuals, 86% had filoplumes on the nape and crown (Clark and Cruz 1989 Clark, Jr., G. A. and J. B. de Cruz. (1989). Functional interpretation of protruding filoplumes in oscines. Condor 91:962-965. Close ).

General

Molt and plumage terminology follows Humphrey and Parkes (1959) as modified by Howell et al. (2003, 2004). Black-and-white Warbler exhibits a Complex Alternate Strategy (cf. Howell et al. 2003, Howell 2010), including complete prebasic molts, a partial preformative molt, and partial prealternate molts in both first and definitive cycles (Stone 1896; Dwight 1900c Dwight, J., Jr. (1900). The sequence of plumages and moults of the passerine birds of New York. Annals of the New York Academy of Sciences 13:73–360. Close ; Oberholser 1974; Cramp and Perrins 1994, Curson et al. 1994 Curson, J., D. Quinn, and D. Beadle (1994). Warblers of the Americas: an Identification Guide. Houghton Mifflin Company, New York, NY, USA. Close ; Dunn and Garrett 1997; Pyle 1997a, 1997b; Figure 4).

Prejuvenile (First Prebasic) Molt

Complete, primarily May–Jun, in the nest. No information on timing or sequence of pennaceous feather irruption and development. Duration of Prejuvenile Molt among individuals probably 6–7 days; presumably completed or near-completed by fledging at day 8–12, although rectrices may require 1–3 extra days to complete growth.

Preformative Molt

"First Prebasic" or "Prebasic I" Molt of Humphrey and Parkes (1959) and some later authors; see revision by Howell et al. (2003). Partial, primarily May–Aug (Figure 4), likely commencing in nest and completing shortly after fledging, on breeding grounds. Includes most or all body feathers and upperwing secondary coverts but no primary coverts, primaries, secondaries, or rectrices.

First And Definitive Prealternate Molts

Partial, primarily Feb–Apr (Figure 4), on non-breeding grounds. Includes most or all head and other body feathers, usually 1–3 tertials, and sometimes 1–2 central rectrices, but few or no wing coverts and no other flight feathers (Pyle 1997b). First and Definitive Prealternate Molts similar in timing and extent, as far as known. Reports that Prealternate Molts can begin as early as Oct on non-breeding grounds (Pyle 1997a) require confirmation; limited body-feather replacement at this time may instead be part of protracted/suspended Preformative and Prebasic Molts.

Definitive Prebasic Molt

Complete, primarily Jun–Sep (Figure 4), on or near breeding grounds, although study needed on relationship between breeding territories and molting grounds. Primaries replaced distally (p1 to p9), secondaries likely replaced proximally from s1 and proximally and distally from the central or innermost tertial (s8 or s9), as typical of passerines, and rectrices probably replaced distally (r1 to r6) on each side of tail, with some variation in sequence possible.

Bill

Pinkish buff in juveniles, becoming dusky with age. Mouth pink. Gape flanges pale yellow (Harrison 1978a Harrison, C. J. O. (1978). A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Toronto, ON, Canada. Close ). In adults blackish with horn-colored base to lower mandible.

Iris

Brown.

Legs And Feet

Pinkish buff in juveniles, becoming dusky with age. In adults dark grayish with yellow-buff soles to the feet, sometimes extending to the back of the lower leg. Distal toe pads usually notched, a possible adaptation for bark foraging (Clark 1973b Clark, Jr., G. A. (1973b). Notched toe pads in climbing oscines. Condor 75:119-120. Close ).

Linear Measurements

Wetmore et al. (Wetmore et al. 1984 Wetmore, A., R. F. Pasquier, and S. L. Olson (1984). The Birds of the Republic of Panama, Part 4-Passeriformes: Hirundinidae (Swallows) to Fringillidae (Finches). Smithsonian Miscellaneous Collections 150, Part 4. Close ) report an overall length of 108-125 mm. Ridgway (Ridgway 1902 Ridgway, R. (1902). The birds of North and Middle America. Part II. United States National Museum Bulletin 50, part 2. Close ) reports adult male total length 109-120 (mean = 115.3), adult female total length 109-118 (mean = 113.8). See Table 1 and Table 2 for other measurements.

Mass

Based on 70 specimens, 8.8-15.2 g (Curson et al. 1994 Curson, J., D. Quinn, and D. Beadle (1994). Warblers of the Americas: an Identification Guide. Houghton Mifflin Company, New York, NY, USA. Close ). One bird captured on a ship in Sep had a body weight of 6.4 g with no fat on furcula or abdomen (Mcclintock et al. 1978 Mcclintock, C. P., T. C. Williams and J. M. Teal. (1978). Autumnal bird migration observed from ships in the western North Atlantic Ocean. Journal of Field Ornithology 49:262-277. Close ). Fall weights (during migration) range from 7.9 to 14.9 g. (Murray and Jehl 1964 Murray, B. G., Jr., and J. R. Jehl Jr. (1964). Weights of autumn migrants from coastal New Jersey. Bird-Banding 35: 253–262. Close ), averaging 11 g. Burtt (Burtt 1986 Burtt, E. H., Jr. (1986). An analysis of physical, physiological, and optical aspects of avian coloration with emphasis on wood-warblers. Ornithological Monographs 38. Close ) reports 11.9 g fall departure weight for Madison, WI. Spring arrival weight at Madison, WI, and Itasca, MN, reported as 10.7 g (Burtt 1986 Burtt, E. H., Jr. (1986). An analysis of physical, physiological, and optical aspects of avian coloration with emphasis on wood-warblers. Ornithological Monographs 38. Close ). Spring migrants captured at Appledore Island, Maine, 10.52 g ±1.03 SD, n = 1185; fall migrants 10.72 g ± 1.14 SD, n = 802 (Horton and Morris 2012). Females weigh less than males (Tordoff and Mengel 1956 Tordoff, H. B., and R. M. Mengel (1956). Studies of birds killed by nocturnal migration. University of Kansas Publication, Museum of Natural History 10(1). Close ) and are smaller in body proportions (Table 1). Mean weights of hatching-year (HY) females and males on fall migration did not differ significantly, whereas the mean weight of after-hatching-year (AHY) males was 1.6 g heavier than for AHY females (Clench and Leberman 1978 Clench, M. H., and R. C. Leberman (1978). Weights of 151 species of Pennsylvania birds analyzed by month, age and sex. Bulletin of Carnegie Museum of Natural History 5. Close ).