During the breeding season (early May to late August), semipalmated plover adults occupy Arctic and sub-Arctic regions of North America. During this period, these birds breed in areas ranging from Alaska to Newfoundland and Nova Scotia.
In order to escape the harsh winters of the sub-Arctic regions, semipalmated plovers undergo a seasonal migration and fly to the southern and western borders of North, Central and South America. Between the months of September to late April, they live along the Pacific coasts of southern California, Mexico, Columbia and Chile. They also inhabit the Atlantic coast from southern Virginia to southern Florida. Semipalmated plovers also inhabit regions along the Gulf Coast from southern Florida to southern Texas. They are occasionally found in the Western Caribbean. Seasonal migratory routes are consistent every year for semipalmated plovers. ("Avibirds European birdguide online", 2010; "Semipalmated Plover (Charadrius semipalmatus)", 2004; "Common Coastal Birds of Florida & the Caribbean", 2001; "Population Dynamics of Semipalmated Plovers (Charadrius semipalmatus) Breeding at Churchill, Manitoba", 2001; Nol and Blanken, 1999)
For spring breeding grounds, these shorebirds prefer flat, open areas on sandy or mossy terrain. They are found on sandy and gravel shorelines, grassy borders of rivers and ponds, wet meadows on fallow croplands, high rocky beaches, as well as sand dunes. They inhabit elevations from sea level to 1525 m above sea level. Semipalmated plovers migrate across the United States and will stopover on lake shores, ponds, or flooded fields. Their nonbreeding, winter habitats include open areas near water such as mudflats, salt marshes, sandy and muddy beaches, lagoons, salt ponds, soft tidal pools, coastal estuaries, lakes, and bays. ("Semipalmated Plover (Charadrius semipalmatus)", 2004; Nol and Blanken, 1999; Swarth, 1990)
Semipalmated plovers are small plovers measuring 18.4 cm in length. They weigh 45 g on average and have wingspans of 48.3 cm.
Semipalmated plover adults have dark-brown upperparts and white underparts in both breeding and nonbreeding plumage. While in breeding plumage males feature a black breastband, a black "mask" over the eyes and across the forecrown, and a small white patch just above the bill. Above the black breastband there is a band of white which also extends across the throat. They feature short, black-tipped, orange bills and orange legs. Female breeding plumage is similar, but overall drabber. Non-breeding plumage is the same for males and females, and is very similar to breeding plumage. Notable differences include a reduction of the black "mask" to surround only the eyes and auriculars, a narrow white supercillium that connects with the white patch above the bill, and a darker bill.
Semipalmated plover chicks have darker downy feathers on their heads and backs. Their forecrowns and wings are mostly white and their bills are almost all black. Their gray feathers are speckled with black spots and their breast bands are narrower than the adults'. As they age, juvenile plovers resemble adults in non-breeding plumage but have yellowish legs.
Slight dimorphism is also present between the two sexes of semipalmated plovers though these differences are hard to distinguish in the field. Females are slightly heavier and have longer wings than males, whereas males have longer toes and bills. These mixed traits are most likely due to variable ecological and sexual selection pressures acting on different characteristics.
There are differences among similar plover species across the world. Semipalmated plovers are almost identical with their European counterparts, ringed plovers (Charadrius hiaticula), except ringed plovers exhibit a few distinguishing traits: 2 partly webbed front toes, shorter and thinner white stripes around the eye region, less black coloration on the head, and a shorter bill. There are also differences among the plover species in North and Central America. For example, a closely related species known as Wilson's plovers (Charadrius wilsonia) have a much larger head, along with a thicker and longer bill than semipalmated plovers. Snowy plovers (Charadrius alexandrinus) have an incomplete breast band, paler upperparts, and black legs. Collared plovers (Charadrius collaris) have narrower and longer bills, reddish upperparts, and flesh-colored legs. (National Audobon Society, 2010; Nol and Blanken, 1999; Spingarn, 1934; Teather and Nol, 1997; Williamson, et al., 2006)
Semipalmated plovers are socially monogamous birds during their breeding season. They pair up on their breeding grounds. Males arrive at their potential nesting sites and perform a fluttering courtship flight, which is accompanied by courtship display calls. This distinctive, slow-flap, deep wing-beat flight takes place at more than 50 meters above the ground and serves to delineate the boundaries of the male’s territory as well as to attract females. On the ground, the male then spreads and depresses his tail feathers, slightly opens his wings, and puffs his feathers while continuously calling.
Once the female has chosen a male’s territory, the male follows the female, appearing to defend her and the territory. The male displays threatening behavior to other male birds by moving toward them with his head down, and wings held slightly out from his body. The male meets the female with somewhat aggressive behavior, in which he chases her with his tail cocked and fanned while making a "chuttering" vocalization. This aggressive behavior declines as the courtship proceeds. The male makes scrapes on the ground with his feet, and the female will assist. While sitting in this new scrape, the female may also perform a tail-fanning display, indicating her decision to choose her mate and his nesting territory.
Copulation then usually occurs after the female’s tail display. The male swings his leg onto the female’s crouched back, the female raises her tail, and the cloacae touch. After copulation, both male and female peck at the ground or preen. It is usually within this scrape that the nest is built. Both sexes incubate and care for the chicks. The pair remains together until the nest is lost or the chick dies; it has been shown that pairs also stay together in subsequent seasons.
The male assures the paternity of his offspring and the monogamy of his paired mate in several ways. When he is not mating with his female he guards her by physically attacking her, which is presumably meant to discourage her from cheating with other males. This is more commonly seen in areas where there is a high likelihood of potential extra-pair partners. Physical attacks may make it more costly for the female to reject a mate's copulation, and may also be used to expel an uncooperative female from a defended territory to vacate space for other potential females. ("Avibirds European birdguide online", 2010; "Common Coastal Birds of Florida & the Caribbean", 2001; Nol and Blanken, 1999; Zharikov and Nol, 2000)
Semipalmated plovers are socially monogamous birds that breed seasonally from May to August. The male arrives before the female to the mating grounds and establishes the nesting territory. The male chooses a patch of dry ground, usually on sandy or gravely substrates with relatively sparse vegetation. Then the male scrapes the boundaries of the nest on the ground with his feet, and lines the nest with material collected nearby, such as leaves and pebbles. When the female arrives to the mating grounds, the male courts her with a slow-flapping, butterfly-like flight.
Once copulation has occurred, the females begin laying their eggs, with the clutch completed within 5 days. There is an interval of 24 to 30 hours between the laying of each egg, with a complete clutch usually contains 4 eggs. For the next 23 to 25 days, both male and female equally contribute to the incubation of the eggs.
The eggs are smooth, glossy, and short with a pear-like shape. They are between 32.4 and 33.1 mm long, and 22.8 to 24.1 mm in width. The average mass of the egg ranges from 8.7 to 9.4 grams. The colors range from light brown to pale, olive buff, with small blotches of black to brownish black. Some eggs are blotched with chestnut brown or sepia color, with a few underlying spots of pale gray.
Hatching of the full clutch can last from 2 to 5 days. Once the chick has broken through the shell, it usually completes its hatching within 12 hours, but can take up to 4 days. Chicks weigh an average 6.6 grams upon hatching. The male takes the hatched chicks a short distance away from the nest in order to brood and feed them, while the mother continues to incubate the unhatched eggs of the nest. Semipalmated plover chicks are precocial and can walk and feed within hours after hatching, but are brooded by their parents up to their fifth day of age. About 15 days after the eggs hatch, the mother abandons her mate and brood, leaving the father as the sole guardian of the nest.
The chicks fully fledge between 22 to 30 days after they have hatched. Semipalmated plovers become sexually mature when they are 2 to 3 years old, and continue to breed yearly after their first breeding experience. ("Avibirds European birdguide online", 2010; "Common Coastal Birds of Florida & the Caribbean", 2001; "Population Dynamics of Semipalmated Plovers (Charadrius semipalmatus) Breeding at Churchill, Manitoba", 2001; Havens, 1970; Nol and Blanken, 1999)
Prior to copulation on the breeding grounds, adult males invest time and energy in finding a suitable site for establishing their nests. Nest site selection plays a very important role on the reproductive success and survival of the offspring. Birds who select nest sites with more pebbles, less vegetative cover, and a smaller percentage of bare mud have greater hatching success than birds who select other kinds of nest sites.
Once the nest is built and eggs have been laid, males appear to be in attendance most of the time, while females are foraging nearby. Once the clutch is completed, males and females equally attend the nest and incubate throughout the day. The males usually incubate during the darkest hours, and switch off with the females every 2 to 5 hours throughout incubation. The incubation period lasts between 23 to 25 days
When the eggs are hatched, the parents brood the chicks immediately. The chicks are precocial and able to find their own food. Young may be led to nearby water areas to feed. When the chicks are about 3 days old, males and females continue to switch off attending the nest but the non-attending adult flies further away. Females abandon their mates and nests 15 days after the eggs have hatched and leave the males as the sole guardians of the brood. As the chicks get older, the adults spend greater amounts of time foraging, and males often leave the nest unattended in order to pursue invading species. The young fledge about 22 to 30 days after they hatch, but the father generally departs before this stage. Juveniles usually flock together before they migrate during the fall. ("Avibirds European birdguide online", 2010; "Philopatry, Nest Site Tenacity, and Mate Fidelity in Semipalmated Plovers (Charadrius semipalmatus) Breeding at Churchill, Manitoba", 1997; Nguyen, et al., 2003; Nol and Blanken, 1999)
The oldest known semipalmated plover in the wild was a banded individual, recovered at 9 years old. About 15% of breeding populations consist of 5 to 6 year old individuals. The lifespan of semipalmated plovers is often limited by the parasites harbored in their bodies. Of 5 shorebird species studied in Churchill, Manitoba, semipalmated plovers contained the most internal parasites, with 99.2% of the examined birds being infected.
Other possible causes of mortality are low temperatures during incubation, which cause parents to abandon eggs and leave them exposed to the freezing temperatures. Birds that continue to incubate in this type of environment usually suffer from low body weights.
Semipalmated plovers also suffer from predators who prey on eggs, chicks and adults. Another limiting factor is competition with other species in the area. For example, competition with killdeer (Charadrius vociferus) arises due to similar nesting habitats and as a result, interspecific aggression may occur on breeding grounds. ("Semipalmated Plover (Charadrius semipalmatus)", 2004; "Common Coastal Birds of Florida & the Caribbean", 2001; Nol and Blanken, 1999)
During their non-breeding season, semipalmated plovers fly in mixed flocks with other shorebirds; these flocks are often compact, but may also be in looser order. At high tide, these birds roost and sleep in dense flocks. Roosting flocks may contain up to 1,100 birds, but are usually much smaller. When foraging, semipalmated plovers prefer to feed by themselves, running a few steps and chasing after their meals.
During their breeding season, semipalmated plovers exhibit little social behavior with other birds and instead pair up with their mates. They form nests and rear their family of chicks in relative isolation, at least 15 meters away from other pairs. Males establish their territory by defending the area and chasing all other birds away.
Occasionally the male’s authority is challenged and extra pair copulation can occur. The social monogamy of these plovers may be breached when an individual continues to maintain its social bond and provide parental assistance to its partner, but seeks copulations outside of the pair. Females can receive indirect benefits from extra pair copulations, such as the “good genes” or good sperm that better quality males can offer to their offspring. Mating with an extra-pair male can also introduce genetic diversity to the female’s offspring, which can make her chicks more adaptable to changing environmental conditions. Extra pair copulations also assure the fertilization of the mother’s clutch in the case that her mate’s sperm is not viable, while also minimizing the possibility of inbreeding. The key to the success of extra pair copulation lies in the fact that parent birds almost universally cannot distinguish between their own and foster offspring, even if the young result from brood parasitism. The only way to prevent females from participating in extra pair copulations is if the males partake in frequent copulations with their mates and guard them intensively. It has been demonstrated that areas of intensive mate guarding result in lower rates of extra pair copulations.
On land, the locomotion of semipalmated plovers includes walking quickly or running with their heads up. They can run up to 4 to 8 meters per minute, occasionally pausing to look for prey. They can also hop on low rocks but rarely climb up vertical objects. These birds forage mostly on land but can wade in shallow water. Adults do not dive but can swim short distances across small water channels during migration, and chicks can swim short distances in order to follow their parents. In the air, the long, slender wings of semipalmated plovers allow them to be fast and power fliers. They can fly at speeds of up to 52 kilometers per hour in strong winds with relative ease. ("Semipalmated Plover (Charadrius semipalmatus)", 2004; "Common Coastal Birds of Florida & the Caribbean", 2001; Nol and Blanken, 1999; "Mating Behavior and Paternity of Socially Monogamous Semipalmated Plovers: Charadrius Semipalmatus Breeding in the Sub-Arctic", 1998)
During the breeding season, semipalmated plovers' home range is up to 3 square kilometers. Pairs nest at least 15 meters from other pairs. Their home range during the winter or migration is unknown. Males usually return to the same breeding territory as the year before. Females are less inclined to return to the same breeding area if they previously experienced breeding failure at that site or changed mates in the subsequent breeding season. (Nol and Blanken, 1999)
Males communicate with other members of their flock with their most common call, which consists of a soft and clear whistle. A quickened version of this common call is used for the purpose of courtship. During courtship, males also perform “butterfly flights” in which they slowly and deliberately beat their wings while flying 50 meters above the ground, around their territory. These flights are used to attract female mates, but are also used to delineate the boundaries of the male’s territory. If there is a threat present, the male will charge towards the object with his head down and wings slightly outwards. Parents communicate the presence of predators to their young with loud, rapid and repeated chutterings, which signal anxiety or nervousness.
Since semipalmated plovers communicate with others through acoustic sounds, they have well developed hearing. They also have very developed visual senses for detecting threats in the area and for capturing food. Like all birds, semipalmated plovers perceive their environment through visual, tactile, auditory and chemical stimuli. ("Avibirds European birdguide online", 2010; Nol and Blanken, 1999)
The diet of Melampus coffeus) and Odostomia laevigata.individuals living near the coast consists of benthic invertebrates from freshwater and marine environments. These include the larvae of long-legged and beach flies, polychaete worms, crustaceans, isopods, decapods, and copepods. They also consume small mollusks including bivalves and gastropods as well as snails such as coffee bean snails (
Ochtebius, spiders, and the larvae of soldier flies and shore flies. On land, these opportunistic feeders also feed on berries or seeds from grasslands or cultivated fields.that are more inland prefer terrestrial invertebrates such as mosquitoes, grasshoppers, beetles of the genus
When semipalmated plovers feed, they search for prey visually, run several steps, and stop. When they stop, they stare, peck and quickly snatch at the prey. Their bills are small but powerful and thus are suitable for snatching prey from the surface as well as hammering hard objects. Semipalmated plovers display foot-trembling behavior while foraging. The tapping or trembling movements of one leg exposes or incites movement of cryptic invertebrates in intertidal zones and grasslands. The vibrations often startle the invertebrate to move on the surface and allow these visual foragers to capture their prey. ("Avibirds European birdguide online", 2010; "Semipalmated Plover (Charadrius semipalmatus)", 2004; Cestari, 2009; Nol and Blanken, 1999)
Semipalmated plovers are vulnerable to predation by large mammals such as Arctic foxes, red foxes, and weasels. They are also vulnerable to larger avian predators such as peregrine falcons, merlins, prairie falcons, common ravens, rough-legged hawks, herring gulls, and parasitic jaegers. These predators usually prey on the eggs, chicks, and adult semipalmated plovers. inhabits areas of sparse vegetation covered with clay, loose stones, pebbles, or sand and rely on their cryptic plumage and the coloration of their eggs as concealment from these predators.
Upon encounter with predators, semipalmated plovers demonstrate a variety of aggressive or passive anti-predator tactics. Semipalmated plovers use an aggressive “mobbing display” with other shorebirds in the vicinity to intimidate or discourage the approach of a potential predator. This defense may be costly to these plovers because it can risk injury or death by the predators. Another, luring defense is demonstrated by parents who stay within sight of predators when predators are near the chicks, and will attempt to distract predators away from the chicks. Incubating semipalmated plovers may employ more passive nest defense behaviors. They use distraction displays in which the plovers run and fly away from the nest. Once they are a certain distance from their eggs, they vocalize loudly to lure the predators away from the nest. The intensity of these calls increases as the eggs near hatching. Other parents go into a crouched position and wait for the threat to pass, relying on their highly cryptic plumage to avoid detection.
One particularly interesting passive defense mechanism demonstrated by semipalmated plovers is “feigning injury." When approached by potential threats, especially humans, these plovers feign injury by fanning out and depressing their tails. In addition, they fake a broken wing, by partly opening and stretching the wings downwards. The bird then skulks off the nest towards the observer and tries to lure it away from the nest. Once the threat is no longer in the vicinity of the nest, the parent takes off and returns to its young.
Different semipalmated plovers also prefer different nesting locations for protection. Most plovers nest in open sites with little vegetation and minimal concealment. They rely on their cryptic plumage for protection and benefit from the site’s good visibility and the early detection of predators. Recent studies have also demonstrated success in plovers that build nests in dense vegetation. Although the visibility around the nest may be compromised, such sites provide microclimates that reduce thermoregulatory costs and provide concealment from some predators.
Furthermore, semipalmated plovers may seek protection from predation by either clumping their nests with other birds in high densities, or by seeking solitary nesting sites. Semipalmated plovers that clump with other birds benefit by communally acting against the threat of a predator and increasing the efficiency of the “mobbing display." Plovers that seek solitary nesting favor optimal spacing between nesting populations in order to avoid detection. (Armstrong and Nol, 1993; Nguyen, et al., 2006; Nguyen, et al., 2004; Nol and Blanken, 1999)
Semipalmated plovers are opportunistic feeders and offer biological control on the small marine freshwater mollusks, worms, crustaceans and insects that they feed on. During the severe locust grasshopper outbreak in the United States between 1873 and 1876, these plovers lived entirely on a diet of these insects and played a big role in keeping the population under control.
Semipalmated plovers are also hosts to a variety of parasites including feather lice, feather mites, cestodes, nematodes, digeneans, and acanthcephalans. These plovers are also food sources for large mammals such as fox and weasels. ("Semipalmated Plover (Charadrius semipalmatus)", 2004; Nol and Blanken, 1999)
There has been limited research conducted on the economic importance of semipalmated plovers. However, the importance of other similar shorebirds of the Charadrius genus suggests that semipalmated plovers may be good indicator species of the health of an ecosystem. A change in the plover population signals an imbalance in the ecosystem and can serve as a warning to monitoring biologists. ("Semipalmated Plover (Charadrius semipalmatus)", 2004; Nol and Blanken, 1999)
There are no known adverse affects ofon humans.
Semipalmated plovers are not threatened or endangered in any area. There are however, current efforts to maintain the major migratory stop sites of the birds across North America. Since semipalmated plovers are long distance migrants, one of the primary objectives is to keep key resting and feeding stops free from human disturbance. These stops are also kept free of contaminants (such as an oil spill) in order to promote the health of these small plovers.
Furthermore, efforts are being taken to minimize human disturbance during breeding seasons. All terrain vehicle (ATV) activity has caused damage to nests in northwestern British Columbia. Vehicles that pull off road onto the roadside gravel habitats have negatively impacted nesting plovers and should be prohibited during the breeding months from May to September. ("Semipalmated Plover (Charadrius semipalmatus)", 2004; Burger, 1997; Nol and Blanken, 1999)
Minimal research has been conducted on Semipalmated plovers during their migratory and wintering periods. Due to the inadequate morphometric data and incomplete molt data, little is known about the transition between the dimorphic appearances of breeding and non-breeding birds. Even less is known about the presence of sexual dimorphism in migratory and wintering birds. Much research still needs to be conducted on these relatively rare shorebirds. (Nol and Blanken, 1999)
Elaine Chang (author), University of Michigan-Ann Arbor, Phil Myers (editor), University of Michigan-Ann Arbor, Rachelle Sterling (editor), Special Projects.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
living in landscapes dominated by human agriculture.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
areas with salty water, usually in coastal marshes and estuaries.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm a