Montana Field Guide

Piping Plover - Charadrius melodus

One of the smaller plovers of North America, weighing only about 46 to 63 grams, the Piping Plover is approximately 17 to 18 cm long with an average wingspan of 48 cm. The back, wings, cheek patches, crown, and breast band are a pale gray. The rest of the body is white, except the tail, which is dark above with white terminal ends and uppertail coverts. The wing tips have a band of black, then a broad band of white, and end in black. In breeding plumage, the breast band changes to black, and is often not a continuous line, with a break in the center. Also at this time, the otherwise singularly gray crown is banded in front with a black stripe that reaches over the head from eye to eye. During the non-breeding season, the short bill is dark, but changes to orange with a dark tip in the breeding season. Throughout the year, the legs are chrome-orange (Haig 1992). The iris is dark. Immature plumage resembles adult non-breeding plumage; juveniles acquire adult plumage in the spring after they fledge.

This plover's common vocalization is described as clear, low-pitched, mellow whistled "peep, peeto" or "peeplo" (Sibley 2000). When agitated, the Piping Plover is known to express an extended series of low, soft whistles "woo-up, woo-up, woo-up, wooo-up..."; while during display, the call repeated in flight is a high-pitched "pipe-pipe-pipe-pipe-pipe..." (Haig 1992).

The other plover species found in Montana of comparable size and coloration is the Semipalmated Plover. The Piping Plover is, however, distinguishable from this other species by its lighter overall appearance. The Semipalmated Plover has much darker upperparts, is larger, has thicker, longer legs and a broad, black stripe through the eye, which the Piping Plover does not. The Piping Plover is also similar in appearance to the Snowy Plover, a rare species in Montana. The dark legs and thinner bill of the Snowy Plover during the breeding season easily separates these two species.

Montana Range

The Piping Plover usually arrives in Montana in early May and leaves the state by late August. The earliest reported observation dates for the species are for April (28 April 1993, Fort Peck Reservoir [MPPRC 1994], 2001; Upper Goose Lake, Sheridan County; [Montana Bird Distribution 2003]). Most of the observations reported in the state are for breeding individuals, or for activity that suggests breeding.

Reports of Piping Plovers during migration are not common, but do occur just east of the Rocky Mountains (Montana Bird Distribution Committee 1996). Although they were known to breed at Bowdoin National Wildlife Refuge and at Fort Peck Reservoir, little attention was paid to the species prior to its listing in 1985. As a result, few observations prior to 1985 are recorded (Montana Bird Distribution 2003).

Piping Plovers primarily select unvegetated sand or pebble beaches on shorelines or islands in freshwater and saline wetlands. Vegetation, if present at all, consists of sparse, scattered clumps (Casey 2000). Open shorelines and sandbars of rivers and large reservoirs in the eastern and north-central portions of the state provide prime breeding habitat (MFWP 2003). In Montana, and throughout the species' range, nesting may occur on a variety of habitat types. If conditions are right, alkali wetlands, lakes, reservoirs, and rivers can all provide the essential features required for nesting. The alkali wetlands and lakes found in the northeastern corner of the state generally contain wide, unvegetated, gravelly, salt-encrusted beaches. Rivers that flood adequately can supply open sandbars or gravelly beaches, as can large reservoirs, with their shoreline beaches, peninsulas, and islands of gravel or sand (USFWS 2003).

Sites with gravel substrate provide the most suitable sites for nesting (MPPRC 1994). One of the most limiting factors to nesting site selection is vegetational encroachment; Piping Plovers avoid areas where vegetation provides cover for potential predators. Fine-textured soils are easier to treat mechanically than rocky or gravelly soils when vegetation is determined as a limiting factor in an area's ability to provide suitable nesting habitat, but fine soils are not typically a preferred nesting substrate (MPPRC 1994). Another, and more important limiting factor in nest site selection is the location of nesting sites in relation to surrounding water levels. Nests are often inundated because water levels are kept unnaturally high throughout the breeding season (and high winds can cause nests to be flooded), or nesting sites are not available, either because of encroaching vegetation or because water levels are so high that beaches are under water during the early part of, and possibly throughout, the nesting season (MPPRC 1994). Nests are simple scrapes dug into the nest substrate which may or may not be lined with pebbles (MPPRC 1994, 1995, Haig 1992).

Food habits studies come from other areas of the species' overall range. Information states that Piping Plover food choices consist of worms, fly larvae, beetles, crustaceans, mollusks, and other invertebrates (Bent 1928). The chicks learn to feed themselves and eat smaller versions of adult food items (Hull 1981). Piping Plovers feed more leisurely than other sandpipers, alternately running and pausing to search for prey (Bent 1928). Open shoreline areas are preferred, and vegetated beaches are avoided (Cuthbert and Wiens 1982).

The Piping Plover eats various small invertebrates, though relatively little information is available on breeding and winter diet. In New Jersey, intertidal polychaetes were the main prey of plovers foraging at night (Staine and Burger 1994). In the Magdalen Islands, Quebec, Staphylinidae, Curculionidae, and Diptera were the organisms most commonly found in fecal droppings (Shaffer and Laporte 1994).

This plover forages along ocean beaches, on intertidal flats, tidal pool edges, etc. Food is obtained from the surface of the substrate, or occasionally by probing into the sand or mud. In Massachusetts, the species was found to prefer mudflat, intertidal, and wrack habitats for foraging (Hoopes et al. 1992). On Assateague Island, bay beaches and island interiors were much more favorable as brood-rearing habitats than were ocean beaches (Patterson et al. 1992).

Information from studies in other areas of the species' range reveal the Piping Plovers defend territory during breeding season and at some winter sites. The nesting territory may or may not contain the foraging area, and the home range during the breeding season generally is confined to the vicinity of the nest. If a nest is destroyed, the home range may be altered before renesting; in Manitoba, shifts of 3 to 100 kilometers have occurred (Haig and Oring 1988).
In the Great Plains, annual survivorship was 66 percent in adults, 60 percent in immatures; it was calculated that a 31 percent increase in chicks fledged per pair (to 1.2 chicks fledged per pair annually) was needed to stabilize the population (Root et al. 1992, Ryan et al. 1993). Data from Massachusetts indicate that mean annual productivity of one chick per pair will maintain a stationary population (Melvin et al. 1992).

Longevity records indicate that only 13 percent of females and 28 percent of the males lived to five years. Eleven years of age is probably the maximum age (Wilcox 1959).

In Duluth Harbor, the species was found to nest within a Common Tern (Sterna hirundo) colony and benefited from the terns' defense against Ring-billed (Larus delawarensis) and Herring Gulls (Larus argentatus) (Niemi and Davis 1979). Great Plains populations are sometimes associated with Least Tern (Sterna antillarum) colonies (Faanes 1983, Hay and Lingle 1981, Dinan, pers. comm.). Most eastern sites also have Least Terns (Vickery, pers. comm., Master, pers. comm.). This plover also has a commensal relationship with American Avocets (Recurvirostra americana) (Prindiville and Ryan 1984). Plovers nesting in areas used by avocets had a 62 percent nesting success, compared to a 29 percent success in areas without avocets. Once hatched, chick survival rates were similar, regardless of avocet presence.

Known, or suspected, predators include mink (Mustela vison), red fox (Vulpes vulpes), skunk (Mephitis mephitis), raccoon (Procyon lotor), several avian predators, and domestic cats (Felis domesticus) and dogs (Canus familiaris) ( Haig 1992).

Limited historic observations and breeding records for the Piping Plover in Montana suggest the rarity of the species. At the time of listing, 1985, the number of breeding pairs in Montana was estimated at 10, although only four nesting pairs were documented in that year (MPPRC 1994). The recovery objective for Piping Plover in Montana is a minimum of 60 nesting pairs for a period of 15 years, a number that was exceeded for the third year in a row in 1995 with 62 nesting pairs reported (MFWP 2003) and in all successive years since (Casey 2000).

Haig and Plissner (1993) indicate 308 adult Piping Plovers were counted in Montana during the 1991 international census, accounting for 105 breeding pairs. A total of 79 sites with appropriate habitat were censused in that year; Piping Plovers were found at 39 of those sites (Haig & Plissner 1993).

The primary nesting locations for Piping Plovers are Medicine Lake National Wildlife Refuge, Northeast Montana Wetland Management District (Sheridan County), Nelson Reservoir, Fort Peck Reservoir, and the Missouri River (MPPRC 1994). Clutch size in Montana appears to be typical with most nests having 5 eggs (range 1 to 4) (Haig 1992, Montana Piping Plover Recovery Committte 1994, 1995). The most recent report of the Montana Piping Plover Recovery Committee (1994) details information on surveys for nesting Piping Plover at Medicine Lake National Wildlife Refuge, the Northeast Montana Wetland Management District (Sheridan County), Charles M. Russell National Wildlife Refuge, Fort Peck Reservoir, Missouri River, Nelson Reservoir, Bowdoin National Wildlife Refuge, Hewitt Lake National Wildlife Refuge, Alkali Lake, Arod Lake, Canyon Ferry Reservoir, Yellowstone River, Powder River, and other water bodies in the state that offer potential habitat for nesting Piping Plovers (MPPRC 1994).

Most reproductive data come from studies in other areas of the species' range. These studies state the breeding season begins when the adults reach the breeding grounds in mid-to late-April or in mid-May in northern parts of the range. The adult males arrive earliest, select beach habitats, and defend established territories against other males (Hull 1981). When adult females arrive at the breeding grounds several weeks later, the males conduct elaborate courtship rituals including aerial displays of circles and figure eights, whistling song, posturing with spread tail and wings, and rapid drumming of feet (Bent 1929, Hull 1981). The Piping Plover can breed the first spring after hatching, and although some birds do not obtain a mate each year, most birds do (Haig 1992).

Nest initiation generally occurs in late-May to early-June. Birds often return to the same nesting area in consecutive years (but few return to natal sites). The species sometimes shifts breeding location by up to several hundred kilometers between consecutive years. Wilcox (1959) has shown that only 20 percent settle at a nest site farther than 1,000 feet from the previous year's locality. Adult females tend to choose new nest sites within the same geographic area with over 50 percent choosing a new nest site over 1,000 feet from the previous year. Previous reproductive success apparently does not increase the probability of returning to specific breeding sites (USFWS 1994). In Manitoba, adults that experienced nest failure the previous year usually changed general nesting location (Haig and Oring 1988).

Generally monogamous during a single breeding season, adults tend to pick new mates each year (Wilcox 1959). In southern Manitoba, most breeders changed mates in subsequent years, but hatching success was lower than for birds that retained mates; some birds changed mates within the breeding season after nest destruction (Haig and Oring 1988).

Nest sites are simple depressions or scrapes in the sand (Bent 1929, Wilcox 1959). The average nest is about 6 to 8 cm in diameter, and is often lined with pebbles, shells, or driftwood to enhance the camouflage effect. Males make the scrapes and may construct additional (unused) nests in their territories, which may be used to deceive predators or may simply reflect over-zealousness (Wilcox 1959, Hull 1981). Occupied nests are generally 50 to 100 meters apart (Wilcox 1959, Cairns 1977, Niemi and Davis 1979, Cuthbert and Wiens 1982).

Egg-laying commences soon after mating (Cuthbert and Wiens 1982, Hull 1981), with an egg laid every second day. The eggs are oval to pyriform, cream or ivory and finely speckled and spotted with black and gray, and 32 x 24 mm in size (Baicich and Harrison 1997). The average clutch size is four (Wilcox 1959) with 3-egg clutches occurring most commonly in replacement clutches. The average number of young fledged per nesting pair usually is two or fewer. The young hatch about 27 to 31 days after egg-laying, and incubation is shared by both adults (Wilcox 1959, Hull 1981).

The young leave the nest about two hours after hatching and are capable of running and swimming. The young remain within about 200 meters of the nest, although they do not return after hatching (Wilcox 1959, Hull 1981, Johnsgard 1979). When disturbed or threatened, the young either freeze or combine short runs with freezing, and blend very effectively into their surroundings (Wilcox 1959, Hull 1981). The adults will feign injury to draw intruders away from the nest or young (Wilcox 1959, Bent 1929). Adults also defend the nest territory against other adult Piping Plovers, gulls, and songbirds (Wilcox 1959, Matteson 1980). First (unsustained) flight has been observed at around 18 days, with chicks molting into first juvenile plumage by day 22 (Zickefoose, pers. comm.).

Nest success depends heavily upon camouflage (Hull 1981). Hatching success ranges widely: 91 percent for undisturbed beaches on Long Island (Wilcox 1959), 76 percent for undisturbed beaches in Nova Scotia (Cairns 1977), 44 percent on relatively undisturbed beaches at Lake of the Woods (Cuthbert and Wiens 1982), and 30 percent maximum at disturbed Michigan beaches (Lambert and Ratcliff 1979). A study in Sheridan County, Montana, and in three northern counties in North Dakota determined that the highest fledgling rates occurred at lakes surrounded by treeless rangeland (Murphy et. al 2000). This species will renest if the first clutch is lost. There is no documentation of more than one brood raised per season in southern Manitoba.

Four specific geographic areas, recognized as providing critically important habitat and identified as essential for the conservation of the species, have been designated as "Critical Habitat Units" in Montana. The designation of critical habitat may require federal agencies to develop special management actions affecting these sites. The four units include prairie alkali wetlands and surrounding shoreline; river channels and associated sandbars and islands; and reservoirs and inland lakes with associated shorelines, peninsulas, and islands (USFWS 2003). Piping Plovers rely on these places for courtship, nesting, foraging, and brood rearing. The first, Unit 1, contains alkali lake and wetland habitat found in Sheridan County. Unit 2 is identified as riverine habitat and includes the Missouri River just south of Wolf Point to the state line, encompassing habitat provided by the sparsely vegetated sandbars, and sandy or gravelly beaches along this stretch of the river. Reservoirs, which include similar sandbars and sandy or gravelly beach habitat, define both Units 3 and 4. Unit 3 includes Fort Peck Reservoir, from south of the dam to and including approximately 26 miles (north to south distance) of the length of Dry Arm. Portions of Bowdoin National Wildlife Refuge, the majority of Lake Bowdoin and the western portion of the Dry Lake, were designated as Unit 4. Piping Plovers nest at Nelson Reservoir north of Bowdoin National Wildlife Refuge, but are not contained within any of the Critical Habitat Units in the state. This reservoir was excluded from the critical habitat designation because of a Memorandum of Understanding between the Bureau of Reclamation, the U.S. Fish and Wildlife Service, and the local irrigation districts. The memorandum, in combination with a biological opinion from the USFWS, guides management actions at this location (USFWS 2003). Management activities include moving nests upslope from areas where flooding of nests is imminent; using nest cages over nest bowls to prevent trampling and predation by avian predators; signing beaches to indicate nesting; beach enhancement (grading or burning unwanted encroaching vegetation); raising island elevation to make room to move nests in years with rising water during the nesting season; the release of captive-reared plovers (Erickson and Prellwitz 1999); and timing spring flow releases from Fort Peck Dam to more closely mimic the natural seasonal flows of the river (MFWP 2003). Other management activities to enhance habitat or affect better protection for this plover include building structures (weirs) to contain water in reservoirs for longer periods during the breeding season, placing gravel on otherwise muddy beaches to create appropriate substrate (Hanebury, personal communication 2003), and reducing human, dog, and vehicular disturbance during nesting (MFWP 2003). The greatest threat to nesting plovers is the loss of nesting sites by high water levels at any time of the year, but especially during the nesting season for it can result in inundation of existing nests (MPPRC 1994). Rising water levels later in the nesting season result in decreasing overall island size, and may assist avian predators to locate nests more easily (Erickson and Prellwitz 1999). These conditions enforce the need to manage reservoirs and dammed rivers in a manner that mimics more natural seasonal fluctuations.