Plumages, Molts, and Structure

Most of this section provides detailed descriptions of plumage for the American Golden-Plover and the Pacific Golden-Plover (Pluvialis fulva) (16 Ridgway, R. (1919). The birds of North and Middle America: A descriptive catalogue of the higher groups, genera, species, and subspecies of birds known to occur in North America, Part 8. U.S. National Museum Bulletin 50. Close , 17 Dement'ev, G. P., R. N. Meklenburtsev, A. M. Sudilovskaya, and E. P. Spangenberg (1968). Birds of the Soviet Union. Volume 2. Israel Program for Scientific Translations, Jerusalem, Israel. Close , 18 Roberts, T. S. (1955). A Manual for the Identification of the Birds of Minnesota and Neighboring States. University of Minnesota Press, Minneapolis, Minnesota, USA. Close , 19 Stresemann, E., and V. Stresemann (1966). Die Mauser der Vögel. Journal für Ornithologie 107, Sonderheft. Close , 20 Palmer, R. S. (1967). Shorebirds of North America. Viking Press, New York, NY, USA. Close , 21 Oberholser, H. C. (1974). The Bird Life of Texas. University of Texas Press, Austin, TX, USA. Close , 22 Prater, A. J., J. H. Marchant, and J. Vuirinen (1977). Guide to the Identification and Aging of Holarctic Waders. British Trust for Ornithology, Tring, United Kingdom. Close , 23 Pym, A. (1982). Identification of Lesser Golden-Plover and status in Britain and Ireland. British Birds 75:112–124. Close , 24 Cramp, S., and K. E. L. Simmons (1983). The Birds of the Western Palearctic, Volume 3: Waders to Gulls. Oxford University Press, Oxford, UK. Close , 12 Johnson, O. W., and P. M. Johnson (1983). Plumage-molt-age relationships in "over- summering" and migratory Lesser Golden-Plovers. Condor 85:406–419. Close , 25 Johnson, O. W. (1985a). Timing of primary molt in first-year Golden-Plovers and some evolutionary implications. Wilson Bulletin 97:237–239. Close , 4 Hayman, P., J. Marchant, and T. Prater (1986) Shorebirds: an identification guide to the waders of the world. Houghton Mifflin Company, Boston, Massachusetts, USA. Close , 5 Dunn, J. L., J. Morlan, and C. P. Wilds (1987). Field identification of forms of Lesser Golden-Plover. International Bird Identification: Proceedings of the 4th International Identification Meeting, Eilat, Israel. Close , 26 Roselaar, C. S. (1990). Identification and occurrence of American and Pacific golden-plover in the Netherlands. Dutch Birding 12:221–232. Close , 10 Golley, M., and A. Stoddart (1991). Identification of American and Pacific golden-plovers. Birding World 4:195–204. Close , 6 Marchant, S., and P. J. Higgins, Editors (1993). Handbook of Australian, New Zealand and Antarctic Birds. Volume 2. Raptors to Lapwings. Oxford University Press, Melbourne, Australia. Close , 7 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close , 27 Paulson, D. (2005). Shorebirds of North America: The Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close , 13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close ; OWJ, unpublished data). Several of these sources (5 Dunn, J. L., J. Morlan, and C. P. Wilds (1987). Field identification of forms of Lesser Golden-Plover. International Bird Identification: Proceedings of the 4th International Identification Meeting, Eilat, Israel. Close , 10 Golley, M., and A. Stoddart (1991). Identification of American and Pacific golden-plovers. Birding World 4:195–204. Close , 27 Paulson, D. (2005). Shorebirds of North America: The Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ) contain particularly helpful photographs of the American Golden-Plover (both sexes), in the plumages described below, often in comparison with the Pacific Golden-Plover. Additional published photos are available (e.g., 28 Rosair, D., and D. Cottridge (1995). Hamlyn Photographic Guide to the Waders of the World. Hamlyn Limited, Melbourne, Australia. Close , 3 Johnson, O. W., and P. M. Johnson (2004). Morphometric features of Pacific and American Golden-Plovers with comments on field identification. Wader Study Group Bulletin 103:42–49. Close , 29 O'Brien, M., R. Crossley, and K. Karlson (2006). The Shorebird Guide. Houghton Mifflin, New York, New York, USA. Close , 30 Chandler, R. (2009). Shorebirds of North America, Europe, and Asia: A Photographic Guide. Princeton University Press, Princeton, NJ, USA. Close ). Research by Byrkjedal and Thompson (31 Byrkjedal, I., and D. B. A. Thompson (1998). Tundra Plovers: The Eurasian, Pacific and American Golden Plovers and Grey Plover. T & AD Poyser Ltd, London, United Kingdom. Close ) complements our descriptions below and includes useful diagrams and sketches. See Pyle (13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close ) for detailed information on molt and age determination and Dwight (32 Dwight, J., Jr. (1900b). The moult of the North American shore birds (Limicolae). Auk 17:368–385. Close ) and Stone (33 Stone, W. (1900). Report on the birds and mammals collected by the McIlhenny Expedition to Pt. Barrow, Alaska. Proceedings of the Academy of Natural Sciences of Philadelphia 1900:4–49. Close ) for early accounts of molts. See Molts for molt and plumage terminology.

American Golden-Plovers have 10 full-length primaries (numbered distally, p1 to p10), 15–16 secondaries (numbered proximally, s1 to s11, and 4–5 tertials, numbered distally, t1 to t5), and 12 rectrices (numbered r1 to r6 distally on each side of the tail); plovers are diastataxic (34 Bostwick, K. S., and M. J. Brady (2002). Phylogenetic analysis of wing feather taxis in birds: Macroevolutionary patterns of genetic drift? Auk 119:943–954. Close ), indicating that a secondary has been lost evolutionarily between what we now term s4 and s5. Their wings are long and pointed while their tails are short and squared. Geographic variation in appearance is minimal (see Systematics: Geographic Variation). No geographic variation in molt strategies has been reported, although variation is marked between the American Golden-Plover and the Pacific Golden-Plover, and molt strategies may vary among potential hybrids between these two species.

Natal Down

During June–July, the natal down is well-developed upon hatching. The crown and back display an overall dull yellowish to whitish color, mottled with fine black markings scattered. The remainder of the head, throat, and nape, except for the crown and black malar stripe, appear solid whitish while the underparts are grayish white. See the image below. Whether sexes are dimorphic is uncertain.

Juvenile Plumage

Juvenile plumage is primarily present from July–October. It resembles the Definitive Basic Plumage, but the feathering is more evenly patterned and worn. The crown, mantle, back, scapulars, and tertials are dark grayish brown, with feathers marked with pale yellow to whitish edges and spots. Rectrices are grayish brown with faintly barred dark brown, with small lateral whitish-yellow spots and fringing at the tips. The lores appear moderately dark forming a indistinct loral smudge; auriculars and neck are spotted and streaked with dirty white and brownish gray. Whitish supercilia are prominent while the upperwing lesser and median coverts share the same background color as their upperparts, with buffy and pale yellowish markings. Their chins are whitish and the chest is gray, spotted with grayish brown markings. The belly and undertail are a bright white as well.

Formative Plumage

Formative plumage is primarily present from December–June. The "First Basic" and/or "Basic I" plumage, as described by Humphrey and Parkes (35 Humphrey, P. S., and K. C. Parkes (1959). An approach to the study of molts and plumages. The Auk 76:1–31. Close ) and some previous authors, is unique among all other Pluvialis plovers. For example, the Preformative Molt includes the juvenile primaries in the American Golden-Plover. This makes the Formative Plumage identifiable in most birds for a brief period in December to February. Following the complete Preformative Molt in January–February, the two age groups are not distinguishable other than by retained juvenile secondaries or suspected variation in the appearance of alternate feathering (see below). During this period, scattered formative feathers can be present among body plumage and upperwing coverts. Many juvenile feathers are likely retained until the First Prealternate Molt. During molt, the juvenile's outer primaries become progressively worn, brown, and pointed and lack molt clines (see below), and the juvenile outer rectrices (r6) are usually drab and unbarred (Figure 385 in 13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close ), allowing separation from birds undergoing Definitive Prebasic Molt (note: some retained basic outer primaries are often just as worn at this time, being 10–12 months rather than 6–8 months in age). Some birds in Formative Plumage are potentially separable by retaining faded juvenile secondaries during Preformative Molt. Between 1 and 9 juvenile middle secondaries (among s1–s9) can be retained (36 Jukema, J., J. G. van Rhijn, P. Olsson, and T. Piersma (2014). In tundra plovers the frequency of inner flight feather replacement varies with length of long-distance flights. Ardea 101:121–132. Close ); it may be possible that outer primaries can be retained in such individuals. Those undergoing complete replacement of remiges become unreliably distinguishable from older birds, although outer primaries may seem fresher than in Definitive Basic Plumage due to the later timing of molts. Sexes are similar, except that dark barring on both juvenile and formative outer rectrices averages slightly more distinct in males than in females (Figure 385 in 13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close ); this allows the determination of some but not all individuals when used alone.

First Alternate Plumage

First Alternate Plumage is present primarily from April–September. First Alternate Plumage is highly variable (although probably not as variable as in the Pacific Golden-Plover). It may closely resemble Definitive Alternate Plumage or display varying degrees of partial alternate feathering, resulting in white mottling. In some cases, birds may closely resemble birds with retained Formative Plumage with a few feathers replaced (cf. ML104118091). This latter appearance is common in individuals who remain on winter grounds for their first summer (see left-hand image below). Such birds may also pose challenges in determining their sex reliably. Further study is required since most birds, after complete molts, cannot be aged on plumage alone. However, some juvenile secondaries can be retained during the Preformative Molt in many birds (36 Jukema, J., J. G. van Rhijn, P. Olsson, and T. Piersma (2014). In tundra plovers the frequency of inner flight feather replacement varies with length of long-distance flights. Ardea 101:121–132. Close ). These birds can be reliably determined as First Alternate Plumage, and they usually show less of a definitive alternate appearance than most birds.

Definitive Basic Plumage

Present primarily from October–March. See Definitive Prebasic Molt for the appearance of breeding birds transitioning into Supplemental or Definitive Basic Plumage before southbound migration. Crowns are dark grayish brown with dull yellow, buffy, and whitish spots and fringes. Feathers on the back and scapulars are grayish brown with white fringes forming a scaled appearance; rump feathers are scaled with gold and dark as in the crown; rectrices are barred pale and dark grayish brown. The sides of the head are grayish with darker auriculars, loral smudge, and prominent whitish supercilia. Upperwing lesser and median coverts are gray brown with whitish margins and tips forming a scaled appearance; tertials are gray brown with indistinct whitish margins and dusky bars; greater coverts, primary coverts, and the remainder of remiges are grayish, the greater coverts with indistinct white and dark bars along edges, the greater and primary coverts with white tips, and the primary shafts dark basally and terminally but white subterminally (especially conspicuous on outer 5–6 primaries). Remiges show molt clines, from more worn inner to fresher outer primaries and fresher outer secondary than inner primary, reflecting previous complete molts (cf. Figure 12B in 13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close ); they may average more worn than in formative birds due to earlier timing of molts. Underparts mostly pale grayish brown with a slight wash of pale yellow; belly and undertail whitish.

During Definitive Prebasic Molt, the plumage of males and females progressively gets less dimorphic as worn alternate feathering is replaced. Following molt, sexes are similar, except that outer rectrices (r6) are about 80% sexually dimorphic with males showing crisply defined dark gray/grayish white or black/white bars and females showing less defined (more somber) coloration (Figure 385 in 13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close ). Definitive Basic and Formative Plumages are separable during molt by the presence of patterned juvenile feathers and narrow worn juvenile flight feathers in the latter versus more evenly fringed basic feathers and molt clines among unmolted remiges in the former.

Second and Definitive Alternate Plumages

Present primarily April–September.

Female. Similar to the Definitive alternate male (below) with black feathering of the face and underparts mottled whitish, grading into a white head-neck stripe, resulting in the latter being less clearly defined than in the males. Auriculars often with distinctive white cheek patches. Occasional female is dark and male-like in appearance (37 Connors, P. G., B. J. McCaffery, and J. L. Maron (1993). Speciation in golden-plovers, Pluvialis dominica and P. fulva: evidence from the breeding grounds. Auk 110:9–20. Close ), but feathering is usually brownish black instead of jet black as in males (OWJ). Differences between male and female Definitive Alternate Plumages were set forth by A. C. Meinertzhagen (see 38 Witherby, H. F., F. C. R. Jourdain, N. T. Ticehurst, and B. W. Tucker (1940). The Handbook of British Birds, Volume 4. H. F. and G. Witherby, London, United Kingdom. Close ) and confirmed in subsequent field studies (39 Van Tyne, J., and W. H. Drury Jr. (1959). The birds of southern Bylot Island, 1954. Occasional Papers of the Museum of Zoology University of Michigan 615:1–37. Close ).

Male. Crown, nape, mantle, scapulars, tertials, and wing cover are dark grayish brown with bolder spots and fringes, mostly yellow, some buffy. The sides of the head and breast have continuous white stripes from the forehead through the supercilia, down the sides of neck to widened, bulbous breast patches, which in some birds almost meet on the midline; frontal band above the base of the upper mandible, sides of the head (below white stripe), and underparts entirely black, a few birds showing scattered white in the vent and undertail coverts. Second Alternate Plumage is likely similar to Definitive Alternate Plumage in most or all males, but a few birds may require an additional cycle, showing mottled whitish feathers, similar to but fewer than found in First Alternate Plumage (above), as is found in the American Golden-Plover. However, these may also be individuals in First Alternate Plumage that have completed the molt of secondaries. Flight feathers are largely similar to those of Definitive Basic Plumage.

Molt and plumage terminology follows Humphrey and Parkes (35 Humphrey, P. S., and K. C. Parkes (1959). An approach to the study of molts and plumages. The Auk 76:1–31. Close ) as modified by Howell et al. (40 Howell, S. N. G., C. Corben, P. Pyle, and D. I. Rogers (2003). The first basic problem: A review of molt and plumage homologies. The Condor 105:635–653. Close ). Under this nomenclature, terminology is based on the evolution of molts along ancestral lineages of birds from ecdysis (molts) of reptiles (cf. 41 Pyle, P., S. N. G. Howell, D. I. Rogers, and C. Corben (2024). Moult terminology: envisioning an evolutionary approach. Journal of Avian Biology 2024:e03169. Close ), rather than on molts relative to breeding season, location, or time of the year, the latter generally referred to as “life-cycle” molt terminology (42 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close ; see also 43 Pyle, P. (2022). Defining moults in migratory birds: A sequence-based approach. Journal of Avian Biology 2022:e02958. Close ). The American Golden-Plover exhibits a Complex Alternate Strategy (cf. 40 Howell, S. N. G., C. Corben, P. Pyle, and D. I. Rogers (2003). The first basic problem: A review of molt and plumage homologies. The Condor 105:635–653. Close ), including complete preformative (except for a few secondaries, see 36 Jukema, J., J. G. van Rhijn, P. Olsson, and T. Piersma (2014). In tundra plovers the frequency of inner flight feather replacement varies with length of long-distance flights. Ardea 101:121–132. Close ) and prebasic molts and limited to partial prealternate molts in both first and definitive cycles (Figure 1). A Definitive Presupplemental Molt of flank feathers has been reported in Pluvialis (44 Jukema, J., and T. Piersma (1987). Special moult of breast and belly feathers during breeding in Golden Plovers Pluvialis apricaria. Ornis Scandinavica 18:157–162. Close , 31 Byrkjedal, I., and D. B. A. Thompson (1998). Tundra Plovers: The Eurasian, Pacific and American Golden Plovers and Grey Plover. T & AD Poyser Ltd, London, United Kingdom. Close , 45 Jukema, J., I. Tulp, and L. Bruinzeel (2003). Differential moult patterns in relation to antipredator behaviour during incubation in four tundra plovers. Ibis 145:270–276. Close ), but confirmation is needed (see 13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close and below). Definitive appearance can be attained at Formative and Second Alternate plumages, although not until the Definitive Basic and/or possibly the Third Alternate Plumage in some males (see Plumages).

Prejuvenile (First Prebasic) Molt

Complete, late June–July, as young mature and forage on the tundra. One “nearly six-day-old male” had no juvenile feathers except for “barely visible” wing quills (46 Parmelee, D. F., H. A. Stephens, and R. H. Schmidt (1967). The birds of Southeastern Victoria Island and adjacent small islands. National Museum of Canada Bulletin 222. Close ). Primaries also erupt at approximately 6 days of age. Prejuvenile Molt progresses rapidly, prior to fledging at <30 d (see Breeding: Young Birds). Otherwise, no detailed information on timing or sequence of pennaceous feather irruption and development.

Preformative Molt

"First Prebasic" and/or "Prebasic I" molt of Humphrey and Parkes (35 Humphrey, P. S., and K. C. Parkes (1959). An approach to the study of molts and plumages. The Auk 76:1–31. Close ) and some previous authors. Molting may start before or after arrival on the overwintering grounds, with body-feather molt occurring primarily from November to early December; molt of flight feathers occurs mostly in December–February, some birds likely extending into March (14 Jukema, J., O. W. Johnson, J. Aldabe, and P. Rocca (2011). Wing and tail moult of American Golden-Plovers Pluvialis dominica on wintering grounds in Uruguay, with confirmation that juveniles replace all primaries during their first non-breeding season. Wader Study Group Bulletin 118:129–131. Close ). Preformative Molt of flight feathers appears to average about a month later than that of the Definitive Prebasic Molt, according to examination of Macaulay Library images (cf. right-hand image under Formative Plumage). Preformative molts differ in extent between the American Golden-Plover and the Pacific Golden-Plover (12 Johnson, O. W., and P. M. Johnson (1983). Plumage-molt-age relationships in "over- summering" and migratory Lesser Golden-Plovers. Condor 85:406–419. Close , 25 Johnson, O. W. (1985a). Timing of primary molt in first-year Golden-Plovers and some evolutionary implications. Wilson Bulletin 97:237–239. Close , 13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close , 14 Jukema, J., O. W. Johnson, J. Aldabe, and P. Rocca (2011). Wing and tail moult of American Golden-Plovers Pluvialis dominica on wintering grounds in Uruguay, with confirmation that juveniles replace all primaries during their first non-breeding season. Wader Study Group Bulletin 118:129–131. Close ), being complete (except for a few secondaries, see 36 Jukema, J., J. G. van Rhijn, P. Olsson, and T. Piersma (2014). In tundra plovers the frequency of inner flight feather replacement varies with length of long-distance flights. Ardea 101:121–132. Close ) in the American Golden-Plover and incomplete in the Pacific Golden-Plover (the latter retains juvenile primaries until Second Prebasic Molt). Some American Golden-Plovers can retain up to 9 inner and middle secondaries (among s1–s9) (36 Jukema, J., J. G. van Rhijn, P. Olsson, and T. Piersma (2014). In tundra plovers the frequency of inner flight feather replacement varies with length of long-distance flights. Ardea 101:121–132. Close ); proportion of birds that undergo a complete Preformative Molt is unknown. Sequences of flight-feather replacement is as in Definitive Prebasic Molt, although sequence of secondary replacement may differ (36 Jukema, J., J. G. van Rhijn, P. Olsson, and T. Piersma (2014). In tundra plovers the frequency of inner flight feather replacement varies with length of long-distance flights. Ardea 101:121–132. Close ); additional study needed.

First Prealternate Molt

Limited to partial, primarily May–June. Unusual in shorebirds, prealternate molts occur almost exclusively at stopover locations during northbound migration, although they can complete on breeding grounds, especially the First Prealternate Molt. Much of this molt (and subsequent Definitive Prealternate Molts) occurs while American Golden-Plovers are en route north (15 Jukema, J., J. B. Dunning Jr., P. Vlas, L. Brierley, and P. Brooks (2015). Morphological variation in spring migrant and wintering American Golden-Plovers Pluvialis dominica. Wader Study 122:128–134. Close ). The First Prealternate Molt averages later and may occur farther north on average than the Definitive Prealternate Molt. Extent of the First Prealternate Molt can approach that of the Definitive Prealternate Molt in some individuals, but molt can apparently be less complete. Replacement of body feathers and wing coverts is variable, ranging from partially to about half or more complete. From 1–4 tertials and/or 1–2 central rectrices occasionally replaced, but averages fewer feathers than in Definitive Prealternate Molt. Birds oversummering on overwintering grounds likely average fewer feathers replaced, possibly very few or none in some birds.

Second and Definitive Prebasic Molts

Complete, primarily July–February (Figure 1); definitive Prebasic Molt of flight feathers averages earlier in timing than during the Preformative Molt (cf. right-hand image under Formative Plumage). Primaries replaced distally (p1 to p10), secondaries replaced proximally from s1 and s5 and distally from the tertials, and rectrices probably replaced distally (r1 to r6) on each side of tail, with some variation occurring.

For breeding birds, Definitive Prebasic Molt can commence on breeding grounds during incubation (Figure 1). Early stages of molt most noticeable on black cheeks and underparts which become mottled with lighter feathers. Molt of body feathers may continue at stopover locations before being completed on the non-breeding (boreal winter) grounds. Molt of primaries and rectrices can occasionally begin on summer grounds or at stopover locations and be suspended for migration, but usually deferred until arrival on (boreal) overwintering grounds (47 Morrison, R. I. G. (1984). Migration system of some New World shorebirds. In Behavior of Marine Animals. Volume 6. Shorebirds: Migration and Foraging Behavior (J. Burger and B. L. Olla, Editors). Plenum Press, New York, NY, USA. pp. 125–202. Close , 36 Jukema, J., J. G. van Rhijn, P. Olsson, and T. Piersma (2014). In tundra plovers the frequency of inner flight feather replacement varies with length of long-distance flights. Ardea 101:121–132. Close ), with less body molt prior to arrival on the overwintering range than in the Pacific Golden-Plover (Pluvialis fulva) (48 Dabbene, R. (1920). Notas sobre los chorlos de Norte América que invernan en la República Argentina. Hornero 2:99–128. Close , 49 Hudson, W. H. (1920) Birds of La Plata. Volume 1. Dent & Sons, London, United Kingdom. Close , 50 Haverschmidt, F. (1969b). The migration of the American Golden-Plover through Surinam. Wilson Bulletin 81:210–211. Close , 51 Belton, W. (1984). Birds of Rio Grande do Sul, Brazil. Pt. 1: Rheidae through Furnariidae. Bulletin of the American Museum of Natural History 4:371–631. Close , 52 Hayes, F. E., S. M. Goodman, J. A. Fox, T. G. Tamayo, and N. E. López (1990). North American bird migrants in Paraguay. Condor 92:947–960. Close , 53 Sick, H. (1993). Birds in Brazil: A Natural History. Princeton University Press, Princeton, New Jersey, USA. Close ). Molt of flight feathers occurs primarily in October–February, with completion as early as late January or early Ferbruary (cf. ML614293540).

Presupplemental Molt resulting in supplemental feathering with possible cryptic function has been described on underparts of the breeding European Golden-Plover (Pluvialis apricaria) in both sexes (44 Jukema, J., and T. Piersma (1987). Special moult of breast and belly feathers during breeding in Golden Plovers Pluvialis apricaria. Ornis Scandinavica 18:157–162. Close , 31 Byrkjedal, I., and D. B. A. Thompson (1998). Tundra Plovers: The Eurasian, Pacific and American Golden Plovers and Grey Plover. T & AD Poyser Ltd, London, United Kingdom. Close ). Whether ventral body molt of nesting American Golden-Plovers involves like elements or simply represents late Prealternate Molt or early Prebasic Molt is unclear (45 Jukema, J., I. Tulp, and L. Bruinzeel (2003). Differential moult patterns in relation to antipredator behaviour during incubation in four tundra plovers. Ibis 145:270–276. Close , 13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close ).

Definitive Prealternate Molt

Partial, primarily April–June (Figure 1), occurring rapidly at spring migration stopover sites or completing on summer grounds. Includes some to most body feathers, up to 90% of secondary coverts, often 1–5 tertials, sometimes 1–2 (occasionally 3–4) central rectrices (occasionally asymmetrical with 1 rectrix of a pair fresh and the other old); males average a greater number of feathers replaced; e.g., in females typically only as much as 40% of wing coverts are replaced (13 Pyle, P. (2008). Identification Guide to North American Birds. Part II: Anatidae to Alcidae. Slate Creek Press, Point Reyes Station, CA, USA. Close ). First birds to begin and complete Prealternate Molt are usually males, with some males achieving full Alternate aspect in about 10 weeks. The possibility that two inserted molts including a Presupplemental Molt occur in spring, one primarily on winter grounds and one primarily at stopover locations, as in other shorebirds, should be investigated (cf. 54 Pyle, P. (2019). Sunset Sanderlings: Digital photography leads to novel insights about the presupplemental molt of the Sanderling. Birding 52:30–41. Close ).

The descriptions below are based on studies from the following linked papers (e.g., 20 Palmer, R. S. (1967). Shorebirds of North America. Viking Press, New York, NY, USA. Close , 21 Oberholser, H. C. (1974). The Bird Life of Texas. University of Texas Press, Austin, TX, USA. Close , 24 Cramp, S., and K. E. L. Simmons (1983). The Birds of the Western Palearctic, Volume 3: Waders to Gulls. Oxford University Press, Oxford, UK. Close , 6 Marchant, S., and P. J. Higgins, Editors (1993). Handbook of Australian, New Zealand and Antarctic Birds. Volume 2. Raptors to Lapwings. Oxford University Press, Melbourne, Australia. Close , 27 Paulson, D. (2005). Shorebirds of North America: The Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ) along with examination of reports from Macaulay Library images.

Bill

The bill remains black throughout all ages of development, including hatchlings and juveniles.

Iris and Facial Skin

The iris is dark brown throughout its entire lifespan.

Tarsi and Toes

The legs and feet vary from gray and grayish black to black in adults. Examination of Macaulay Library images indicates that the American Golden-Plover adult males in breeding areas tend to have darker black legs compared to females, a difference less noticeable in the Pacific Golden-Plover. Grayish tones display more often in juveniles and first-year birds (OWJ). In hatchlings, the legs and feet are relatively large and dark grayish brown to gray in color.

Linear Measurements

Representative data are summarized in Appendix 1. For additional linear measurements, see 55 Sutton, G. M., and D. F. Parmelee (1956). On certain charadriiform birds of Baffin Island. Wilson Bulletin 68:210–223. Close , 39 Van Tyne, J., and W. H. Drury Jr. (1959). The birds of southern Bylot Island, 1954. Occasional Papers of the Museum of Zoology University of Michigan 615:1–37. Close , 56 Blake, E. R. (1977). Manual of Neotropical Birds. Volume 1. Spheniscidae (Penguins) to Laridae (Gulls and Allies). University of Chicago Press, Chicago, IL, USA. Close , 16 Ridgway, R. (1919). The birds of North and Middle America: A descriptive catalogue of the higher groups, genera, species, and subspecies of birds known to occur in North America, Part 8. U.S. National Museum Bulletin 50. Close , 57 Bailey, A. M. (1948). Birds of Arctic Alaska. Colorado Museum of Natural History, Popular Series 8. Close , 58 Vaurie, C. (1964). Systematic notes on palearctic birds. No. 53. Charadriidae: the genera Charadrius and Pluvialis. American Museum Novitates 2177. Close , 4 Hayman, P., J. Marchant, and T. Prater (1986) Shorebirds: an identification guide to the waders of the world. Houghton Mifflin Company, Boston, Massachusetts, USA. Close , and 15 Jukema, J., J. B. Dunning Jr., P. Vlas, L. Brierley, and P. Brooks (2015). Morphological variation in spring migrant and wintering American Golden-Plovers Pluvialis dominica. Wader Study 122:128–134. Close . There are no significant differences in linear measurements between the sexes.

Mass

Upon arrival at the breeding grounds, most plovers carry fat reserves (sizes of reserves vary greatly). Limited and sometimes conflicting information on mass change during subsequent weeks may reflect regional variations in food supplies and weather. Mass changes between males and females during the breeding season are mixed. Body mass of plovers sampled in northcentral Alaska from May through July (Irving 1960) decreased by 4–9% in males and 10–15% in females (59 Irving, L. (1960). Birds of Anaktuvuk Pass Kobuk and Old Crow: A study in Arctic adaptation. U.S. National Museum Bulletin 217. Close ). At Utqiagvik, Alaska, females averaged 14% heavier than males during May through June, suggesting that females were less stressed than males (F. A. Pitelka, unpublished data; see 9 Connors, P. G. (1983). Taxonomy, distribution, and evolution of golden plovers (Pluvialis dominica and Pluvialis fulva). Auk 100:607–620. Close ). At Churchill, Manitoba, limited data (Appendix 1) indicated that females were less stressed (P = 0.05), whereas males and females on nesting grounds in the Seward Peninsula, Alaska, did not differ in mass (P = 0.39; Appendix 1). For additional mass measurements, see 60 Musacchia, X. J. (1953). A study of lipids in arctic migratory birds. Condor 55:305–312. Close , 39 Van Tyne, J., and W. H. Drury Jr. (1959). The birds of southern Bylot Island, 1954. Occasional Papers of the Museum of Zoology University of Michigan 615:1–37. Close , 61 Johnston, D. W. (1964). Ecologic aspects of lipid deposition in some postbreeding arctic birds. Ecology 45:848–852. Close , 62 Stodola, K. W., B. J. O'Neal, M. G. Alessi, J. L. Deppe, T. R. Dallas, T. A. Beveroth, T. J. Benson, and M. P. Ward (2014). Stopover ecology of American Golden-Plovers (Pluvialis dominica) in Midwestern agricultural fields. Condor 116:162–172. Close , and 15 Jukema, J., J. B. Dunning Jr., P. Vlas, L. Brierley, and P. Brooks (2015). Morphological variation in spring migrant and wintering American Golden-Plovers Pluvialis dominica. Wader Study 122:128–134. Close .