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Northern Pintail

Anas acuta

Order:
Anseriformes
Family:
Anatidae
Sections

Appearance

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Figure 4. Annual cycle of migration, breeding (eggs and young), and molt (male, female) of Northern Pintails

Annual cycle of migration, breeding (eggs and young), and molt (male, female) of Northern Pintails breeding in the Prairie Pothole Region of north-central U.S. and southern Canada. For variation among regions, see text and Appendix 1. Thick lines show peak activity, thin lines off-peak. Dashed line in Migration indicates molt migration.

Medium-sized duck. Total length: adult males 57–76 cm, females 51–63 cm. Sexually dimorphic plumage.

Both sexes distinguished from other dabblers by slim profile, long, narrow neck, and pointed tail.  Definitive Alternate male is readily distinguished from other North American ducks by a combination of chocolate brown head, white neck and underparts, and very long central rectrices, although the rectrices may not obtain their full length until late fall. Male Long-tailed Duck (Clangula hyemalis) is the only other North American duck with elongated central rectrices.

Female distinguished from other female ducks by slender proportions (see above), pointed tail, mottled dull brown or bronze (rarely with some green) speculum, and mottled to spotted dark gray to black bill. Both sexes distinguished in flight by long, slender appearance and long, narrow wings.

Similar Species

Closely related Eaton's Pintail (Anas eatoni) in s. Indian Ocean is considerably smaller with shorter neck and central tail feathers; alternate plumage of male is duller, resembling female; plumage of female is dark reddish brown. White-cheeked Pintail (A. bahamensis), with which Northern Pintail overlaps in parts of the Neotropics, is readily distinguished by its white cheek patch, and a red patch at the base of the bill.

Detailed Description

Northern Pintails have 10 full-length primaries, 14-15 secondaries (including 4-5 tertials or tertial-like feathers), and usually 16 rectrices. Little or no geographic variation in appearance (see Systematics: Geographic Variation) or molt strategies reported; sex-specific variation in molt and plumage strategies described below.

Plumages

Following based primarily on detailed plumage descriptions of Oberholser (1974), Palmer (Palmer 1976), Cramp and Simmons (1977), Bellrose (Bellrose 1980), and Madge and Burns (1988); see Carney (1964, Carney 1992), Duncan (Duncan 1985), Baker (1993), Esler and Grand (1994), and Pyle (2008) for age/sex-related criteria. See Molts (above) and Pyle (2005, 2013) for revision of terminology resulting in bright male feathering of winter and spring being formative and basic plumages and cryptic summer feathering being alternate plumage. Sexes differ slightly in Juvenile Plumage (wing feathers only) and more substantially in later plumages. Definitive Plumage typically assumed at Second Basic Plumage.

Natal Down

Present primarily May-Jul, on natal territory and at brooding locations. Completely downy; lacks yellow of other dabbling ducks. Crown and eye stripe blotchy brown; upperparts and wing brownish gray, darkest on rump; scapulars and rump with linear white spots; underparts whitish, lightly tinged pale yellowish pink on throat, chin, and belly (Nelson 1992a).

Juvenile (First Basic) Plumage

Present primarily Jun-Aug.

Male. Overall brown to buffy; like Definitive Basic Female but upperparts darker and less clearly marked. Head to upper breast and sides streaked dark on buff; mantle brownish sepia with buffy transverse barring and edging; scapulars with narrow buff edging; rectrices sepia, barred and edged with creamy buff, the tips notched. Upperwing coverts narrow and rounded; lesser and median coverts gray-brown, often with indistinct pale fringes proximally; greater coverts narrow, medium gray-brown with broad cinnamon tips (Pyle 2008). Primaries and primary coverts brown with paler inner webs and indistinctly darker tips, narrow and tapered; outer secondaries (speculum) with greenish or bronzy purple iridescent on s5-s10, subterminal black band, and buff to whitish terminal band (Pyle 2008); secondary next to speculum with wide black outer web; tertials brownish gray with darker outer webs and buffy margin distally. Underparts whitish buff with some dark streaks underwing coverts gray; axillars white.

Female. Similar to male except mantle feathers with longitudinal barring, and more and broader streaking ventrally; greater coverts with less-distinct buff tips distally (Pyle 2008); outer webs of s5-s10 (speculum) dull cinnamon with little or no sheen (Pyle 2008).

Formative Plumage

Combination of "First Basic" or Basic I" and "First Alternate" or "Alternate I" Plumages of Palmer (Palmer 1976) and others; see above and Pyle (2005, 2008, 2013). Present primarily Aug-Mar in females and Aug-Jun in males.

Male. Body plumage variably colorful, similar to Definitive Basic Male but duller and tinged brownish or with retained brown feathers in rump; rectrices variably mixed with abraded, brown juvenile feathers with notches at tips, and replaced formative rectrices without notches (can be entirely juvenile or entirely formative), resembling those of Definitive male but central pair (r1) not as elongated; wing feathers as in Juvenile male except some lesser coverts replaced, grayer; 1-4 tertials often replaced, more elongated and pointed than juvenile feathers, darker brown with blackish inner webs.

Female. Similar to Definitive Basic female except wing feathers (except tertials and some proximal wing coverts) retained juvenile, worn, and as described under Juvenile Plumage; tail usually with a few to many juvenile feathers, worn and notched, the central rectrices not as elongated as in Definitive females.

Formative Plumage best separated from Definitive Basic Plumages by wing and tail feather criteria: median coverts with pale fringing (males) or triangular markings contiguous with feather edge (females); greater coverts and speculum duller by sex, as in Juvenile Plumage; outer primaries thinner, browner, and more abraded, and tail often mixed with notched and abraded juvenile rectrices (Duncan 1985, Pyle 2008).

First And Definitive Supplemental And Alternate PlumageS

Considered "Second Basic"/"Basic II" and "Definitive Basic" Plumages, respectively, by Palmer (Palmer 1976) and others; see above and Pyle (2005, 2008, 2013). Following description largely encompasses possible Supplemental Plumages (see above), although possible Feb-May molt in males may not change appearance markedly; discrete plumage appearances described here present primarily Feb-Sep in females and Jun-Sep in males. Similar to Formative and Definitive Basic Plumages, respectively, but upperpart feathering, tertials, some proximal secondary coverts, and at least the central rectrices largely replaced with variably tinged and patterned, rounded and filamentous brownish feathers, providing crypsis for nesting and wing molt, especially in males.

Male. Head, throat, and neck medium brownish, unmarked or with fine dark streaks; upperparts brownish to grayish with broad dark barring, coarse lines, or heavy vermiculations, the scapular edging pale and narrow and the uppertail coverts very dark, irregularly margined with buff; central rectrices (r1) usually brown, wider and shorter than definitive feathers, the next pair (r2) usually replaced, broad and brown with buff edge, and the other rectrices more buff than gray and broader distally if replaced. Wing as in Formative or Definitive Basic males except 1-4 tertials and up to 20% of proximal secondary coverts replaced, brownish or grayish with pale fringing or indistinct dark internal markings. Throat, chin, breast, sides, and flanks variably mottled with irregular brown spotting or other markings; lower breast and belly nearly white.

Female. Typically browner, less grayish, than Definitive Basic female. Head and neck buffy brownish to tan, paling nearly to white on chin, with more diffuse brownish streaking than in Definitive Basic female; mantle feathers blackish brown with wide tan to cinnamon margins; scapulars blackish, margined tan; some to all central rectrices usually replaced, dusky brown, barred and broadly margined buffy tan, with central pair broader and shorter than in Definitive Basic female. Wing as in Formative or Definitive Basic females except 1-4 tertials and up to 20% of proximal secondary coverts replaced, brownish with pale fringing or indistinct dark internal markings. Underparts plain or spotted to somewhat streaked; breast brownish with dark markings; sides, flanks, and undertail coverts whitish, plain or with dusky spots or streaks.

Males and females in First and Definitive plumages separated using same criteria described under Formative and Definitive Basic Plumages; juvenile outer primaries and remaining juvenile rectrices even more bleached and abraded.

Definitive Basic Plumage

Considered "Definitive Alternate" Plumage by Palmer (Palmer 1976) and others; see above and Pyle (2005, 2008, 2013). Present primarily Sep-Feb in females and Sep-Jun in males (appearance may include inserted male plumage in Mar-Jun):

Male. Most of head medium to chocolate brown with purplish sheen laterally and white stripes extending from foreneck penetrating up each side of black nape; mantle and sides grayish (vermiculated black on white); narrow, tapering scapulars black with buff or tan to white edges; rump grayish; central uppertail coverts gray with buff edges. Central pair of rectrices (r1) black, narrowly pointed, long (to about 22 cm), and slightly upcurled; succeeding pairs have diminishing amount of black, to outer pair (r8) nearly or all white. Upperwing lesser and median coverts medium brown-gray; greater coverts broad, gray tinged slightly brownish, with broad subterminal tawny band (Pyle 2008); primaries and primary coverts sepia with grayer inner webs and indistinct dusky tips, broader, glossier, and more truncate than juvenile feathers; outer secondaries (wing speculum) partly metallic bronzy greenish to coppery with subterminal black band and white terminal band (Pyle 2008); secondary proximal to speculum dark with distinct, bright light gray to buff outer web; tertials long, tapering, and pointed, medium gray with dark inner wens. Foreneck to vent white; vent to tail black; flank yellowish tan blending to white below; underwing coverts grayish and whitish, the lesser coverts vermiculated gray and white, the median and primary coverts whitish, and the greater coverts white with indistinct white tips, and the axillars white, mottled, or patterned gray (Carney 1992:37).

Female. Crown heavily and broadly streaked tan to cinnamon, paling to whitish chin and throat with narrow streaks; mantle and rump rufous to blackish brown with buffy to tan markings and margins; scapulars very dark, with some internal light markings and pale margins; rectrices pointed, the central pair (r1) considerably longer (20-25 cm) than next pair and nearly all black or with transverse whitish barring, and other pairs dark with buff or whitish internal markings and edges. Upperwing lesser and median coverts gray-brown with buffy or nearly white margins; greater coverts broad, gray-brown to light gray with whitish tips (Pyle 2008); primaries and primary coverts as in male; outer secondaries (wing speculum) with brownish, gray-brown, or partly bronzy or greenish outer web with narrow black subterminal band and broad white tips both webs (Pyle 2008); secondary proximal to speculum brownish gray with light gray internal band and wide white margin; tertials long, tapering, and pointed, brownish with buff margins and indistinct internal markings. Upper breast buffy to tan; lower breast and belly white, sometimes with a few dusky spots; undertail coverts streaked white; underwing coverts and axillars as in male except lesser coverts brownish barred whitish (Carney 1992:37).

Definitive Basic Plumage best separated from Formative Plumage by wing and tail feather criteria: median and greater coverts and speculum brighter by sex; outer primaries broader, grayer, glossier, and less abraded; tail without notched brown rectrices (Duncan 1985, Pyle 2008).

Aberrant Plumage Coloration

Albinistic Northern Pintails recorded (Maynard 1985).

Molts

General

Molt and plumage terminology follows Humphrey and Parkes (1959) as modified by Howell et al. (2003, 2004) and Pyle (2005, 2013). Northern Pintail exhibits a Complex Alternate Strategy (cf. Howell et al. 2003, Howell 2010), including complete prebasic molts, a partial preformative molt, and limited-to-partial prealternate molts in both first and definitive cycles Bent 1923; Oberholser 1974; Palmer 1976; Cramp and Simmons 1977; Miller 1986b; Hohman et al. 1992; Smith and Sheeley 1993b; Pyle 2005, 2008; Figure 4). Two body molts during the first summer and fall (including an Auxiliary Preformative Molt) has been reported but probably does not occur; it is possible, however, that extra Definitive Presupplemental Molts occur in both sexes (see below). Note revised molt and plumage terminology of Pyle (2005, 2013) reverses previous terminology for prebasic and prealternate body-feather molt; thus, prealternate molts result in cryptic summer body feathers for wing molt, and prebasic molts result in colorful plumages of males.

Prejuvenile (First Prebasic) Molt

Complete, primarily Jun-Aug, in brooding habitats nearest natal site (see Breeding: Young Birds). Prejuvenile molt begins by 3 wk when scapular, flank, and rectrix feathers begin to emerge. At 4 wk belly fully feathered, feathers emerge on rump, breast, head, and neck; primaries beginning to emerge; rectrices 3.5-5.0 cm long. At 5 wk primaries about 0.6 cm; wing speculum developing. At 6 wk completely feathered except for remnant of down on neck, back, rump, and wings. Flight attained at 46-57 d in wild birds (Southwick 1953, Bellrose 1980) and as early as 36 and 43 d in Alaska (Bellrose 1980). At fledging feathers still growing on dorsum; Preformative Molt beginning on head, neck, and underparts.

Preformative Molt

Combination of "First Prebasic" and "First Prealternate" (or "Alternate I") Molt of Palmer (Palmer 1976) and other authors; see Pyle (2005, 2008, 2013) and Howell (2010) for revised terminology. Descriptions of two body molts in first Aug-Oct likely arose from attempted application of confused molt terminology to protracted Prejuvenile and Preformative Molts as body surface area expands in post-fledging ducks (Pyle 2005, 2008). In Northern Pintail, Preformative Molt partial to incomplete, primarily Jul-Nov, commencing on breeding grounds, continuing on non-breeding or specific molting grounds (see Definitive Prebasic Molt), often completing on winter grounds. Includes some to all body feathers, a few to some proximal upperwing secondary coverts, usually 1-4 tertials and tertial coverts, and no to (occasionally) all 16 rectrices, but no primaries, primary coverts, or secondaries besides tertials.

Commences about 60 d after hatching. In males Preformative Molt occurs primarily Sep-Nov in Sacramento Valley, CA (Miller 1986b); extends through Dec in Southern High Plains of Texas (Smith and Sheeley 1993b). Molt in females peaks Sep-Oct in all feather groups except tertials, which do not molt in Sep; slightly later in Texas birds (not sampled in Sep). Long scapulars and innermost secondaries often not fully grown until very late fall or early winter, generally about 1 mo later than adults. Both sexes molt earlier during falls with above-average rainfall (Miller 1986b, Smith and Sheeley 1993b).

First And Definitive Prealternate And Presupplemental Molts

According to traditional terminology, only one partial body molt reported to occur in each sex of breeding Anas ducks; in Northern Pintail occurs primarily Jan-Apr in females and May-Aug in males (Palmer 1976); Pyle 2005, 2008). In males, also known as "eclipsed molt." These body molts formerly considered part of "Second Prebasic" and "Definitive Prebasic" Molts, respectively (along with flight-feather replacement in Jul-Sep), but homologous molt strategies in waterfowl suggest they are inserted molts, evolved to produce cryptic plumage for breeding in females and wing molt in both sexes (Pyle 2005, Howell 2010; see Definitive Prebasic Molt).

Considered sex-specific Prealternate Molts (Jan-Apr in females, Jun-Jul in males) according to revised terminologies (Pyle 2008); however, such a sex-specific difference in molt timing unusual in birds, suggesting both sexes of ancestral duck taxa may have had two inserted molts (Prealternate and Presupplemental), that later showed sex-specific adaptations (Pyle 2007, 2013; Howell 2010). Male Anas ducks, including Northern Pintail, may have limited inserted molt in Feb-Apr and females may have limited inserted molt in Jun-Jul, corresponding with partial molts of other sex, and indicating existence of Presupplemental Molts (Pyle 2013). In such case, whether Prealternate precedes Presupplemental Molt, or vice versa, depends on evolution of these molts within Anatidae and is not known or presupposed at this time (Pyle 2007, 2013).

In Northern Pintail these two molts combined include some to all upperpart feathers, often a few (up to 20%) proximal upperwing secondary coverts, no to 4 tertials and no to all rectrices but no other secondaries or primaries (Pyle 2008). The less-extensive molt in each sex (Feb-May in males and Jun-Jul in females), if it occurs, is limited to scattered head and upperpart feathers. These molts may average slightly later and less extensive in first cycle than in definitive cycle but otherwise similar in timing, sequence, and extent. In females, head-body feathering replaced Jan-Mar, peaking in Feb for birds in California (Miller 1986b), in Mar for birds in Texas (Smith and Sheeley 1993b). In males most molting begins early summer (Jun-Jul) about 12 d after deserting female (Oring 1964a).

Definitive Prebasic Molt

Complete, primarily Jul-Dec (Figure 4). Molt commences with synchronous flight-feather replacement following breeding. For males occurs primarily on secluded molting and staging grounds (e.g., in centers of large marshes), often far from breeding grounds, as in other waterfowl (Salomonsen 1968, Hohman et al. 1992); females can shed flight feathers in brooding locations but small numbers of females also migrate to molting or (occasionally) winter grounds before replacing remiges (Miller et al. 1992, R. R. Cox pers. comm.). Males can begin wing molt in Jun but more typically Jul; flightless period 27-30 d (Oring 1964a, Cox 1993). Sedentary (nonflying) period of radio-marked females in California estimated at 36 d; 9th primary grew an average of 4.2 mm/d in captive females (Miller et al. 1992).

Complete body molt commences during wing molt, formerly considered "Definitive Prealternate Molt" by Palmer (Palmer 1976) and others, but completeness and homologies with molts of geese and other ancestral waterfowl indicates it is part of Definitive Prebasic Molt (Pyle 2005, 2008, 2013; Howell 2010). Low molt intensity after regaining flight suggests males may postpone this body molt until fall migration or until arrival on wintering areas (Miller 1986b, Cox 1993). Molt of males in California (Miller 1986b) and Texas (Smith and Sheeley 1993b) peaks in Oct; body molt in Texas continues into Dec whereas in California, only scapulars and rectrices being replaced in Dec. In females molt activity in California and Texas peaked in Oct (Miller 1986b, Smith and Sheeley 1993b). Males molt earlier with above-average rainfall; in females molt in several tracts more active during Nov-Dec in wet winters (Miller 1986b, Smith and Sheeley 1993b).

Bare Parts

Bill

In ducklings bluish gray or olive gray, bluish on upper mandible (Nelson 1992a); in juveniles dull dusky to blackish with indistinct dark gray stripe on side; in males black with bluish gray stripes (duller in first year, brighter in adults) on sides flowing over top of bill to nail; in females duller black to slaty blue, sometimes with dull stripe on sides, and heavily spotted in nesting season (MRM).

Iris

Dark brown or dark cinnamon brown in both sexes; yellowish brown in some adults.

Legs And Feet

In juveniles and ducklings bluish gray or olive-gray; in adult male medium bluish gray to black with darker joints and black webs; in adult female bluish gray, webs slightly darker.

Linear Measurements

Males larger than females, adult and immatures similarly sized; no geographic variation in linear measurements. Detailed linear measurements in Appendix 2 .

Mass

See Appendix 2 . Body mass varies through the reproductive season owing to production of eggs and reproductive tissues and incubation (Mann and Sedinger 1993, Esler and Grand 1994b, G. L. Krapu pers. comm.), and through the winter period owing to condition after fall migration, influence of foods consumed and time spent feeding, courtship behavior and pair status, and weather/habitat conditions (Miller 1986c, Smith and Sheeley 1993b); thus, average values differ among sources, with wide ranges. Mass is lowest during the flightless period (Keith and Stanislawski 1960).

Internal organ and fat and protein mass available in Miller (Miller 1986c), Smith and Sheeley (Smith and Sheeley 1993a), and Mann and Sedinger (Mann and Sedinger 1993).

Recommended Citation

Clark, R. G., J. P. Fleskes, K. L. Guyn, D. A. Haukos, J. E. Austin, and M. R. Miller (2014). Northern Pintail (Anas acuta), version 2.0. In The Birds of North America (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.163