Behavior

Locomotion

Walking, Running, Hopping

Commonly walk and run. Often stand on 1 leg while loafing or roosting; if disturbed, may hop on that leg for considerable distance before changing gait. Except with certain topographic features of tundra landscape (see Sounds: vocalizations, above), locomotion does not involve elevated perches. Three atypical situations recorded on Oahu, HI: group of Pacific Golden-Plovers flushed from pond alighted on dead branches of surrounding trees and remained there for several minutes, 2 birds (separate instances) seen standing on upper rail of chain-link fences (P. Bruner and A. Bruner pers. comm.); 1 bird observed walking and foraging atop dense, pruned hedge approximately 0.5 m tall (OWJ).

Flight

Capable of swift and extended flight. Paulson (1993) ranks these plovers as “the high speed champions among shorebirds,” with speeds perhaps exceeding 180 kph. Other estimates 105–110 kph (see Johnston and McFarlane 1967, Johnson et al. 1989). According to radar measurements in various arctic regions, ground speeds of migrating shorebird flocks (some composed of American or Pacific golden-plovers) often >72 kph ranging as high as 136 kph (Richardson 1979; Alerstam and Gudmundsson 1999a,b; Gudmundsson et al. 2002; Alerstam et al. 2007; Hedenström et al. 2009). Mean ground speed of migrants (likely including Pacific Golden-Plovers) passing Oahu was 63 kph (Kloeckner et al. 1982, Williams et al. 1986), similar measurement at Guam 60.7 kph (Williams and Williams 1988). A radio-tagged Pacific Golden-Plover traveled from Oahu to the Alaska Peninsula at minimum ground speed of 56 kph, actual speed probably faster as immediate detection of bird upon arrival in Alaska was unlikely (Johnson et al. 2004a).

Geolocations recorded by data loggers attached to Pacific Golden-Plovers (n = 8) that migrated in 2009 from wintering grounds on Oahu to nesting grounds in Alaska and then returned to the same winter territories on Oahu indicated variable flight performance (presumably related to strength and direction of winds) during transpacific passages: on the northward flight mean ground speed and flight time to landfall were 65 kph (range 47-106 kph) and 72 h (range 44-90 h), means for the southward return flight were 58 kph (range 38-112 kph) and 87 h (range 35-112 h); flight speeds of individuals during both north and south migrations varied irregularly with the rate sometimes relatively slow on some legs (probably while encountering headwinds) and sometimes very fast on others (likely with push from tailwinds) ranging to approximately 185 kph (OWJ, R. Goodwill, R. Gold, unpubl. data).

Swimming And Diving

Non-aquatic species (see Sauer 1962). In the above data logger study there was no evidence of seawater contact during migrations, thus Pacific Golden-Plovers are able to remain aloft for extended periods. The sighting of a plover on the ocean surface during migratory periods would probably indicate a bird forced to rest on water by dense fog (see Piersma et al. 2002), fatigue or injury.

Self-Maintenance

Preening, Head-Scratching, Stretching, Bathing, Anting

Preening and stretching usually accompany periods of loafing. Head-scratching is indirect, foot passed over lowered wing (Sauer 1962, OWJ). Bathing observed on Oahu wintering grounds (see Food Habits: drinking, pellet-casting, and defecation, above) involves vigorous wing-flapping, body sometimes immersed in shallow water. On Maui, a wintering plover (probably the same bird) seen on several occasions bathing in a backyard birdbath (S. Southworth, in litt.). Migrant juvenile American Golden-Plovers observed bathing in Iowa wetlands during fall 1988 and 2000 (M. Kenne in litt.). No reports of bathing on nesting grounds. No records of anting.

Sleeping, Roosting

Wintering Pacific Golden-Plovers in Hawaii sleep intermittently during daylight hours, squatting or standing on 1 leg, either with head resting on shoulders and bill forward or with head turned and bill tucked beneath scapulars. Presumably, American Golden-Plover similar, but no reports. Brief intervals of sleep likely on breeding grounds; no information available.

Roost in flocks during non-breeding season. In Argentina, American Golden-Plovers join other shorebirds on multispecific nocturnal roosts "at the edge of lagoons and swamps" (Myers 1984). Pacific Golden-Plovers on winter range use varied nocturnal roosting sites, including beaches, rocky points, levees, tops of low mangroves (Marchant and Higgins 1993, Minton and Whitelaw 2000), flat rooftops (Johnson and Nakamura 1981), rocky offshore islands (Johnson et al. 1981), hillsides, parking lots (OWJ), barren lava flows (P. Bruner in litt.). Observations of Pacific Golden-Plovers in Hawaii (Johnson et al. 1981, Johnson and Nakamura 1981, OWJ) indicate: first birds appear at nocturnal roosts around sunset, with most arriving after dark; roosting flocks vary from a few to 300+ individuals; aggression common when spacing < about 1.5 m; aggressive interactions occur throughout the night; birds depart roosts before dawn and return to territories or communal foraging areas (see Spacing and Agonistic Behavior, below); nocturnal roosts occur annually on same rooftops; diurnal aggregations of loafing, sleeping, preening birds form on rooftops, large grassy areas, wetlands, etc., these individuals usually more tolerant (spacing often ≤ 0.5 m) than birds at nocturnal roosts.

Rooftop roosting by Pacific Golden-Plovers has been reported elsewhere on the winter range (see Johnson and Nakamura1981) attesting to the adaptability of this species in urban environments. Notably, this behavior also has been observed in Eurasian Golden-Plovers during the non-breeding season at several sites in England (Calbrade et al. 2001). The latter birds roost on rooftops during the day then depart to feeding areas at night (i.e., the reverse of the pattern in Hawaii). There are no reports of American Golden-Plovers using rooftops.

Daily Time Budget

Only study concerned seasonal activity patterns among wintering Pacific Golden-Plovers on Oahu, HI; these birds spent majority of daylight hours (68%) foraging (A. Bruner pers. comm.).

Spacing And Agonistic Behavior

Breeding Territoriality

Highly territorial on breeding grounds. Territory sizes estimated at roughly: American Golden-Plovers, 25 ha on North Slope of Alaska (PGC); Pacific Golden-Plovers, 25–50 ha on St. Lawrence I., AK (Sauer 1962), 50 ha in e. Siberia (Khlebosolov 1985); both species, 10–50 ha on Seward Peninsula (PGC). Large size of territory produces “gradient of defense” (Sauer 1962) where distraction displays and defensive behaviors (see below) are particularly intense in zone around nest, less frequent peripherally. Most of pair activity focused on territory, but considerable foraging occurs elsewhere as nonincubating bird (especially female) is often absent from territory (Drury 1961, Sauer 1962, OWJ, PGC; see below, Breeding: incubation; also Demography and Populations: range). Extraterritorial feeding probably of a communal nature on specific sites (Sauer 1962, OWJ). Interyear fidelity to breeding territory high in males, very low in females (see Demography and Populations: range, below).

Territories established and defended with ground and aerial displays, vocalizations, chases, fights. Complex Whistle (see Sounds: vocalizations, above) a frequent warning from ground as intruders fly by. Males advertise with wide-ranging Butterfly Display flight (Drury 1961) while vocalizing Repetitive Call; latter is interspecifically unique (see Sounds: vocalizations, above). Flight uses slow, measured wingbeats, wings almost vertical at top of stroke; performed at heights of 10–100 m above ground (J. T. Nichols inBent 1929, Drury 1961, Sauer 1962, Parmelee et al. 1967, Kondratiev 1982, Connors et al. 1993, Byrkjedal and Thompson 1998). Usually Butterfly Display flight commences with normal wingbeat as plover departs ground silently; when bird reaches display altitude, wingbeat changes and calling begins. In Pacific Golden-Plover, takeoff occasionally involves gradual ascending flutter of rapid, shallow wingbeats; sometimes accompanied by truncated version of Repetitive Call. Fluttering ascent has not been detected in American Golden-Plover, although in one instance variant of Repetitive Call was heard during ascent (OWJ). According to Byrkjedal and Thompson (1998), Pacific Golden-Plover butterfly wing-stroke is deeper (“wings sometimes seem almost to meet above the back and below the belly”) than that of American Golden-Plover. Butterfly Display flights may cross territories of other males, who often respond with similar flight. Flights end in rapid, nearly vertical descent with wings held in V above back; Complex Whistles frequent as bird nears ground.

Neighboring males perform coordinated parallel marches with Head-to-tail Rocking (see below) and often with Complex Whistles; whether these behaviors define territorial boundary or occur in zone near potential nest site is unknown (OWJ, PGC). More vigorous ground actions involve running toward and chasing intruder, pursuer with head down, back horizontal, back feathers ruffled, breast and side feathers fluffed out; accompanying vocalizations (see Sounds: vocalizations, above) typically the Complex Whistle (both species) and a chatter (Pacific Golden-Plover; Sauer 1962). All on-ground interactions and confrontations are punctuated by Head-to-tail Rocking motion in which elevation of head and slight backward leaning of body occur simultaneously; movement performed quickly, at varying rates up to several times/minute. Head-to-tail Rocking (first noted in wintering Pacific Golden-Plovers by Johnson et al. 1981) signals excitement and is common in many on-ground situations. Occurs on both breeding and wintering ranges when birds interact, respond to presence of human, etc.

Both sexes, but especially male, conduct aerial chases. Male chases may be brief and direct or long (2+ min) and meandering, with birds 1–3 m apart (occasionally making physical contact) and 1–4 m above ground (PGC); sometimes at much greater heights (Drury 1961). Flight is rapid with quick turns and other erratic maneuvers. Chase flights of American Golden-Plover almost always with specific aggressive vocalization (see Sounds: vocalizations, above). Pursuer in aerial chase is frequently an incubating bird disturbed by intruder either landing or flying nearby. Aerial chases often followed by Butterfly Display flights of male combatants.

The foregoing aggressive behaviors occasionally escalate to contact fighting, with birds trying to peck at feathers, head, or legs of opponent. These attempts occur on the ground, while jumping and fluttering with or above opponent, or in short flights directed at adversary on the ground (OWJ, PGC); accompanied by frequent Complex Whistles and Head-to-tail Rocking; during on-ground phases of these skirmishes, both wings often held vertically over back. Where sympatric on Seward Peninsula, Alaska, American and Pacific golden-plovers appear to be equally aggressive toward neighbors or intruding individuals, no matter which species it is (Connors et al. 1993). Prolonged disputes sometimes occur: an interspecific bout between 2 males lasted 105 min and involved parallel marching, aerial chases, contact fights, and repeated displays and vocalizations (Connors et al. 1993); 2 male Pacific Golden-Plovers behaved similarly for at least 40 min (OWJ). Lengthy interactions are probably most frequent in early spring when territories are being established, and may be a more common occurrence than presently recognized.

Both species defend their breeding territories against other bird species. Partial list: Pacific Golden-Plover especially agonistic toward Ruddy Turnstone, also intolerant of Eurasian Golden-Plover; American Golden-Plover aggressive toward Dunlin (Calidris alpina), Rock Sandpiper (Calidris ptilocnemis), Common Snipe (Gallinago gallinago); both species aggressive toward Black-bellied Plover, Western Sandpiper (Calidris mauri), and Lapland Longspur (Calcarius lapponicus) (Sauer 1962, Connors et al. 1993, P. Bruner in litt., OWJ, PGC). For additional comments about intra- and interspecific agonistic behaviors, see Byrkjedal and Thompson (1998).

Winter Territoriality And Nonterritoriality

Many individuals defend feeding territories on wintering grounds; others are nonterritorial. For reviews of these nonbreeding season behaviors in plovers and other shorebirds, see Myers et al. 1979, Colwell 2000. Territory sizes much smaller than on breeding grounds: 0.1–0.3 ha, American Golden-Plover in Argentina (Myers and Myers 1979); 0.05–0.4 ha, Pacific Golden-Plover on Oahu, HI (Johnson et al. 1981, 1989).

Establishment and defense of territories require displays and contact fights. Among Pacific Golden-Plovers in Hawaii, these behaviors occur throughout the wintering season but are more frequent in early fall when territories are being established by new birds and re-established by previous tenants. Four behaviors, described from least to most aggressive, of Pacific Golden-Plovers at territorial boundaries are: (1) Confrontational Challenge in which birds alertly watch each other at distance of about ≤1.0 m, alternately stand and walk slowly with legs relatively stiff, usually droop wing and often tilt tail toward opponent, peck at ground picking up grass, pebbles, and other debris which is then flung to the side; (2) Parallel Marching which may alternate with behavior 1, frequently droop wing and tilt tail as above; (3) Crouch-running at intruder, head down, back feathers ruffled, pursuer attempting to peck other bird; (4) Contact Fights in which birds peck and buffet each other, sometimes on the ground, usually while fluttering or during brief, erratic flights, often rather violent with each bird pulling feathers from its opponent.

On-ground behaviors are accompanied by Head-to-tail Rocking; this movement most frequent during behaviors 1 and 2, but also occurs during pauses in behaviors 3 and 4. Cessation of hostility variable: sometimes birds simply drift apart (particularly behaviors 1 and 2), loser may run or fly off (especially behaviors 3 and 4), occasionally 1 bird will sit (often with tail and rear of body somewhat elevated) apparently signaling submission (Johnson et al. 1981, OWJ). Agitated calls similar to Complex Whistle given with head-pumping are uttered frequently during behaviors 3 and 4, seldom during 1 and 2 (OWJ). Confrontation (behavior 1) usually brief (minutes); other behaviors (especially 3 and 4) sometimes of short duration but may continue for extended periods exceeding at least 3 h (OWJ). Crouch-run often involved in maintenance of space among nonterritorial and roosting birds. Much less known concerning territorial interactions of American Golden-Plover; displays include Parallel Marching with wing drooped, tail fanned and tilted toward opponent, back feathers ruffled (Myers et al. 1979).

Other details concerning Pacific Golden-Plover in Hawaii (Johnson et al. 1981, 2001c, 1989, OWJ): territories are held by adults and juveniles of both sexes, males predominating in what appear to be the choicest habitats; locations of territories varied, lawns especially favored (see Habitat: winter range, above); territorial birds defend same territories daily for entire wintering period, typically retire to roosts at night, occasionally found on territories during night; individuals typically reoccupy the identical territory defended in the previous season (i.e., very high interyear fidelity, see Demography and Populations: range, below); as in Black-bellied Plover (Townshend 1985), selection of either territorial or nonterritorial mode of life appears to occur in juvenile during first wintering season and may remain fixed thereafter; nonterritorial birds also site faithful (but at lower rate than territorial birds) to same communal grounds annually; human activities may temporarily displace territorial plovers, which often join nonterritorial birds, sometimes forming large aggregations on areas safe from disturbance.

In Buenos Aires Province, Argentina, American Golden-Plovers are territorial on grasslands and inland wetlands. Plovers occupy their territories most of the day, except for mid-afternoon when territorial and non-territorial birds merge into large flocks for drinking and bathing at local water sources (Myers and Myers 1979). Territories of Buff-breasted Sandpipers (Tryngites subruficollis) wintering in the same region are superimposed on those of American Golden-Plover, with neither species showing interspecific territoriality (Myers 1980). By contrast, Pacific Golden-Plovers in Hawaii do not readily share territorial space and frequently attack other bird species (OWJ).

Sexual Behavior

Mating System

Socially monogamous, with pairs remaining together for the breeding season and for replacement nesting (see Demography and Populations: measures of breeding activity, below). Both sexes defend territory (male with greater vigor), incubate, and tend young prior to fledging (see Breeding: parental care, below). Studies of banded birds on Seward Peninsula indicate that remating in subsequent years is much less likely than new pairing, despite high site fidelity of males (Johnson et al. 1993, 2001b, OWJ; see Demography and Populations: range, below).

Pair Bond

The male Butterfly Display flight clearly advertises the territory and may also serve to attract a female (Miller 1996, Byrkjedal and Thompson 1998, OWJ, PGC). Males sometimes perform this flight above or alongside a flying female (Sauer 1962, PGC). These flights often end with both birds landing, wings held aloft in a V while calling with Complex Whistles.

Several other displays (Drury 1961, Sauer 1962, Parmelee et al. 1967, OWJ, PGC) also appear to function in pair-bonding and/or as prerequisites to copulation. Six are described briefly here: (1) on ground performance by both sexes of Complex Whistles and Head-to-tail Rocking; (2) Scraping Display where male uses breast and feet (and probably bill) to form nest scrape on tundra or occasionally on snow, often picking up bits of vegetation during display; (3) Wing-Stretch, in which male stretches wings vertically, head held low; (4) Torpedo Posture of male with bill, head, and back horizontal, back feathers usually ruffled, wings sometimes raised; either remains stationary or runs toward female; (5) Erect Posture in which male stands very upright, neck stretched upward, motionless for up to 30 s, female close and observant; and (6) Tipping, in which male (possibly giving a quiet trill; Sauer 1962) holds body rigid and straight but tipped forward with bill almost touching ground, tail high exposing undertail to female who sometimes sits on ground or in nest scrape.

Copulation follows brief pursuit of female; alternatively, male faces female, depresses tail, then mounts and copulates. Copulations brief, usually 1–4 s. Foregoing displays (also see Byrkjedal and Thompson 1998) known in both species, except Erect Posture not observed in Pacific Golden-Plover. Order and relationships of displays not understood.

Extra-Pair Copulations

Appears to occur rarely in American Golden-Plover; one study found extra-pair paternity in about 2% of offspring from 40 families near Barrow (S. Yezerinac and R. Lanctot, unpubl. data). Similar pattern also occurs in Pacific Golden-Plover (OWJ, R. Gold, and R. Goodwill, study in progress). Presumably, EPCs are associated with the habit of females to forage at considerable distance from nest when not incubating (see Demography and Populations: range, below). Sperm length of 67.2 µm (as index to sperm competition) in American Golden-Plover similar to sperm length of other shorebirds considered as monogamous (Johnson and Briskie 1999).

Social And Interspecific Behavior

Flocking characteristic of premigrants and migrants. No evidence of either intra- or interspecific sociality between these plovers during breeding season, except birds somewhat gregarious on extraterritorial foraging areas (OWJ). Breeding American Golden-Plovers at Churchill relatively tolerant toward Short-billed Dowitchers (Limnodromus griseus); association with attentive, vigilant plovers may benefit dowitchers (Byrkjedal 1989b). Similar association between Dunlin and Pacific Golden-Plover (beneficial for Dunlin) occurs on Yamal Peninsula and perhaps also on St. Lawrence I. Details of these relationships (“paging” of plovers by other species) are discussed by Byrkjedal and Thompson (1998).

Among wintering birds, territorial individuals are intolerant and often highly aggressive; nonterritorial birds forage communally but maintain spacing through low-intensity aggression. Most wintering birds aggregate at nighttime roosts, where agonistic interactions are frequent in Pacific Golden-Plover and likely in American Golden-Plover. See earlier comments under Self-Maintenance and Spacing and Agonistic Behavior.

Predation

Kinds Of Predators And Manner Of Predation

Taken by a variety of avian and mammalian predators on breeding and wintering grounds. Most significant losses probably eggs and young (see Demography and Populations: causes of mortality, below).

Response To Predators

On Breeding Grounds. No “acceptable information on the escape tactics of plovers” when attacked by raptors (Lima 1993). Observations related to Sauer (1962) by St. Lawrence I., AK, resident suggest that premigrant Pacific Golden-Plovers under attack from Gyrfalcons (Falco rusticolus) attempt to out-climb the predators.

Nine behavioral responses of breeding birds at/or near nest have been observed; behaviors 1–4 are responses to aerial predators, 5–9 to ground predators: (1) sit tight and sink more deeply into nest; (2) flatten with head outstretched, body motionless; (3) fly from nest and stand silently some distance away; (4) attack the predator; (5) sneak away from nest silently; (6) depart noisily from nest while predator is still at a considerable distance; (7) sit tight until intruder is relatively close; (8) perform specialized distraction displays to lure predator away; and (9) make aerial attack (Sauer 1962, Byrkjedal 1989b, OWJ, PGC).

At Churchill, American Golden-Plovers reacted to Herring Gulls (Larus argentatus) with behavior 1, to Parasitic Jaegers (Stercorarius parasiticus) and Northern Shrike (Lanius excubitor) with behavior 2, to Northern Harriers (Circus cyaneus) with behavior 3, and were never observed attacking or mobbing any avian predator (Byrkjedal 1989b). According to Sauer (1962), Pacific Golden-Plovers on St. Lawrence I., AK, responded to Parasitic and Long-tailed (Stercorarius longicaudus) jaegers, Glaucous Gulls (Larus hyperboreus), Black-legged Kittiwakes (Rissa tridactyla), and Common Ravens (Corvus corax) by either “crouching and remaining silent” [presumably equivalent to behaviors 1 and 2], or attacking with “fierce and swift aggressive flights.” Other Alaska observations: male Pacific Golden-Plover seen attacking Long-tailed Jaeger (Kuskokwim River delta, Williamson 1957; Seward Peninsula, P. Bruner in litt.); incubating American Golden-Plover reacted to several nearby Long-tailed Jaegers with behavior 1 (Seward Peninsula, P. Bruner in litt.); and foraging Pacific Golden-Plovers (off duty and away from nests) responded to Parasitic and Long-tailed Jaegers with behavior 2 (Seward Peninsula, OWJ). We have not observed attacking or mobbing by American Golden-Plovers on the Seward Peninsula.

Aggression toward avian predators (behavior 4 above) occurs only during the breeding season and only in some populations (preceding comments; also see Drury 1961, Sordahl 1981, McCaffery 1982). Possible factors accounting for variable responses among populations (see McCaffery 1982, Byrkjedal 1989b) include: relative risk (e.g., if Pomarine Jaeger [Stercorarius pomarinus] predominates in the area, attacking or mobbing might be maladaptive), presence of other mobbing species to ward off predators (as with aggressive Whimbrels [Numenius phaeopus] in the Churchill region), and benefits of cryptic strategies associated with behaviors 1, 2, and 3. McCaffery’s (1982) account of interaction between American Golden-Plover and Long-tailed Jaeger attests to potential ferocity of these encounters: jaeger attempting to rob plover nest grabbed attacking plover with its bill and began flying off with it; plover struggled free and continued attack; despite plover’s efforts, jaeger eventually succeeded in stealing an egg. Pacific Golden-Plovers on the Taimyr Peninsula were reported 5 times less likely to attack aerial predators than Black-bellied Plovers (Larsen and Grundetjern (1997).

Responses to ground predator generally involve conspicuous, noisy actions to confuse and distract the intruder. Alarm/Distraction Calls (see Sounds: vocalizations, above) are given while standing, walking, or running, after bird performs behaviors 5 or 7, or coincident to behavior 6 (see above). If distractive calling is ineffective and predator threatens nest or brood, bird resorts to behaviors 8 or 9. Calling is often very agitated, and always punctuated with Head-to-tail Rocking.

Human generally evokes same noisy behaviors as ground predators (Sauer 1962, Byrkjedal 1989b), but some birds are extremely wary and leave nest stealthily (behavior 5), often ≥200 m in advance of observer ([“early surreptitious departure”, Gochfeld 1984]; Tulp et al. 2000, OWJ). After sneaking well clear of nest, bird either walks or flies far enough to disappear over hill, ridge, etc., or remains in view at considerable distance calling and/or foraging, occasionally performing distant distraction displays. Stealthy departure especially characteristic of Pacific Golden-Plover, and most likely to occur in both species during first few days of incubation. Generally, these birds do not return while observer is present even if nest found by intruder.

Distraction displays (behavior 8 above) are similar in both species (Murie 1946, Drury 1961, Sauer 1962, Parmelee et al. 1967, Byrkjedal 1989b, OWJ, PGC). Repertoires include: Tail-Down Run—head low, tail depressed, plumage not ruffled; Rodent-Run—bird crouched, plumage fluffed, slightly outstretched wings drooped and quivering, tail down usually dragging on ground; Injury Feigning—1 or both wings extended and flapping as if unable to fly (performed during slow run, or while creeping with wings beating on ground as if “rowing,” or in stationary position either standing or prostrate); Stationary Wing-Spread Display—bird crouched or prostrate, facing intruder, wings outstretched and motionless, tail fanned and either erect or depressed; False Brooding—rarely, a disturbed bird will sit near intruder as if on another nest. Distractions are spirited and varied, displays rapidly transition from one to another. Three of these displays are shown in Figure 3.

Plaintive Alarm/Distraction Calls are mostly absent during distraction displays (Byrkjedal 1989b, OWJ), but do occur during brief pauses in the latter. Males give more vigorous distractions than females. Male American Golden-Plovers are particularly impressive, displaying over extended periods and often approaching intruder to within ≤ 1.0 m. Some Pacific Golden-Plovers behave similarly, but many are more wary, tending to perform at much greater distance and for shorter period; often cease display and walk or fly away.

When observer locates a nest and does not follow displaying bird away from it, plover often returns and initiates new display (“re-entrapment” of the intruder; Gochfeld 1984). This may occur several times, thereafter tendency is for bird to remain aloof and alarm-call, sometimes calling alternates with displays performed at considerable distance from observer. If observer now stays motionless at the nest, bird often ceases displays but continues alarm-calling while either standing or running about, occasionally pausing to quickly snatch up an insect or other item of prey. Movements by intruder (such as passing one’s hand over the nest) frequently will draw the bird back to the nest and trigger another bout of distraction behaviors (OWJ). Distractions performed mostly by disturbed, incubating bird. Off-duty mate (especially male) frequently within earshot and returns to agitated partner, sometimes enters into displays, but often simply watches and calls excitedly. The hypothesis that motivational conflicts between escape, aggression, and incubation govern distraction behavior was rejected in studies of American Golden-Plovers by Byrkjedal (1991). His findings suggest adaptive choice rather than mechanical response. The responses of nesting plovers to human intruders are further described along with drawings by Byrkjedal (1989b), and by Byrkjedal and Thompson (1998).

Observations of plovers attacking mammals (behavior 9 above): American Golden-Plovers—red foxes (Vulpes fulva; Seward Peninsula [OWJ]), caribou (Rangifer tarandus; n. Alaska [Miller et al. 1985]); Pacific Golden-Plovers—arctic foxes (Alopex lagopus; St. Lawrence I. [Sauer 1962]). Sauer described 3 species sometimes entering into Pacific Golden-Plover/fox interaction: plovers attacked fox, agitation attracted Ruddy Turnstones who joined in mobbing fox, plovers then ignored fox and attacked turnstones, turnstones battled with both plovers and fox and finally drove fox from plover territory. Human/plover interaction progresses only to distraction behavior; observer at nest does not provoke attack. However, Sauer (1962) recorded an unusual instance in which Pacific Golden-Plovers did attack him by “diving sharply . . . and flying in low tight circles”. This atypical situation was probably linked to a territorial dispute between the plovers and Ruddy Turnstones that was occurring at the same time.

On Wintering Grounds. Relatively little information. Presence of raptors caused American Golden-Plovers in Argentina to sound alarm calls (Myers 1980)

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