There are a few subspecies of Charadrius alexendrinus. Charadrius alexandrinus occidentalis are birds on the west coast of South America. C. a. tenuirostris breed on the Gulf Coast (east of Louisiana), Bahama Islands, north coast of the Yucatan Peninsula, Greater and Lesser Antilles, and islands off the north coast of Venezuela. C. a. nivosus are located in the United States and in Mexico. Red-capped Plovers (C. ruficapillus) of Australia and White-fronted Plovers (C. marginatus) of Africa were once thought to be subspecies of the Snowy Plover, but now are regarded as separate species.
(Page et al. 1995)
Perception Channels: visual ; tactile ; acoustic ; chemical
Breeding populations of Snowy Plovers along the Pacific Coast of U.S. and Baja California are listed as threatened by the U.S. Fish and Wildlife Service. Snowy Plovers are also threatened in Oregon, Florida, and Puerto Rico. They are endangered in Washington, and Alabama. They are a species of special concern in California.
On U.S coasts, habitat degradation, caused by recreation and expanding beach-front development, has caused a decline in the size of breeding populations.
Some beaches have been closed in Oregon to protect the Snowy Plovers' breeding grounds. Individual nests in coastal Oregon and Monterey Bay, California, has been fenced in to improve hatching success in those areas. There has been a removal of feral red foxes by U.S. Fish and Wildlife Service in Monterey Bay, California to improve adult and chick survival rates.
(Page et al. 1995)
US Migratory Bird Act: protected
US Federal List: threatened ; no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
The main foods eaten by Snowy Plovers are terrestrial and aquatic invertebrates. On the Pacific Coast of North America, these include mole crabs, polychaetes, amphipods, sand hoppers, tanadacians, flies, beetles, clams, and ostracods. The foods eaten in San Francisco Bay and in freshwater ponds include flies, beetles, moths, and lepidopteran caterpillars. In saline and alkaline lakes of the Great Basin, Snowy Plovers feed on flies, beetles, hemipterans, and brine shrimp. Sources of food in salt flats of the Great Plains include flies, beetles, grasshoppers, lepidopterans, and beetles. In the Gulf Coast, the bird feeds on small crustaceans, mollusks, marine worms, aquatic insects, and seeds.
Snowy Plovers forage on beaches, tide flats, salt flats, and salt ponds. At beaches, the bird gathers food from sand surfaces, kelp, marine-mammal carcasses, and above and below the average high water line. Birds that are inland search for food on the shores of lakes, reservoirs, ponds, braided river channels, and playas.
When hunting their prey, Snowy Plovers usually pause, look, run, and then seize their prey from the surface of the beach or the tide flat. Above the high-tide line on California beaches, Snowy Plovers search for food at the bases of low growing plants. In Mono Lake, California, Snowy Plovers feed on brine fly larvae (Ephydridae). They often shake the larvae before swallowing them. The birds will sometimes lower their head and charge with their mouth open into a group of adult flies on the ground while snapping their bill. The bill snaps about two to three times to crush the captured flies before swallowing them. This charging method is also used to capture isolated insects on California beaches. Another behavior sometimes used before feeding is to tremble one foot in shallow water or on a wet substrate.
(Page et al. 1995)
Charadrius alexandrinus breeds on most continents. In North America they breed locally in the western interior and on the Pacific and Gulf coasts. They also breed on the islands in the Caribbean and on coasts in Central America. In South America, they breed on the Humboldt Current coast and on the western coast. In Eurasia, breeding is more widespread in the interior and they also occur on the coasts of Asia, Europe, and northern Africa.
(Paulson, 1993)
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Snowy Plovers are primarily found on sand beaches, though they also forage on nearby mud flats, especially after breeding season. They also spend time on dune systems, coastal lagoons, inland steppes, sand deserts, tidal flats, dry salt flats, and large sandy rivers and lakes where there is little vegetation.
(Richards, 1988)
Average lifespan
Status: wild: 132 months.
Charadrius alexandrinus are one of the smallest plovers, but they have proportionally longer legs. Plumage varies throughout the world with the American Snowy Plover being the palest. The upper parts of the body are pale in color. Breeding males have a small white forehead, black forecrown band, and a slightly reddish colored hindcrown. There is also a black eye band below a slim white brow. Male Snowy Plovers display a black shoulder patch and a complete white collar. Under parts of the bird are wholly white. Female Snowy Plovers have the same pattern as the male, but brown areas replace the black areas. In both sexes, the legs are dark gray, the eyes are large and black, and the bill is black and slender. North American Snowy Plovers have the same general pattern as Kentish Plovers (the name of Snowy Plovers in Europe), but the upper parts of the North American bird are a pale sandy gray color, and the breeding males have a pale fawn hindcrown. The legs are also a paler color in Snowy Plovers than in Kentish Plovers. In flight, Snowy Plovers can be distinguished by their narrow white wing stripe and a partial dark bar at the tip of their tail ( picture).
(Richards, 1988)
Range mass: 34 to 58 g.
Other Physical Features: endothermic ; bilateral symmetry
In western North America, Snowy Plovers are facultatively polyandrous. Most Snowy Plovers breed in the first nesting season after hatching. Depending on season and location, this varies anywhere between 260-360 days after hatching.
Males solicit females from their territories by calling and standing. The male then runs to a spot in the nest and begins scraping. The female begins scraping as the male steps out, and she settles into the nest. The male bows next to the female several times with his head pointed to the ground. While bowing, he flashes the white on his tail to the female. The female then steps out of the nest to run about 0.5-2.0 m. She stands with her body fairly parallel to the ground. The male then stands directly behind her and begins kicking his legs high. He then jumps on her back. While on her back, he shifts his weight alternately from one leg to the other. Both birds then shift their tails side-to-side with increasing speed. At the moment of intercourse, the male uses his bill to grab the back of the female's neck, and both birds fall backwards with their wings flapping.
The first season of brooding varies geographically. In Puerto Rico, egg-laying begins in January. In Florida, it occurs during the last week of March. In California, egg-laying begins around the beginning of March. Depending on location, the dates of the first clutches range from the middle of March until the middle of May. There may be two or even three brooding seasons, but the last clutch will typically be laid before the middle of July.
Clutch size is normally three eggs. Eggs are laid both during the day and at night. Both sexes take turns sitting or standing over the eggs, and both sexes have a single abdominal incubation patch. Incubation period varies with location and season. On average, the incubation season is 26-32 days.
Small cracks appear up to 8 days before hatching. Tapping of the chicks can be easily heard up to 3-4 days before hatching, and peeping can be heard 1-2 days before hatching. Eggs can hatch at any time of the day or night. Young birds are precocial after hatching.
(Page et al. 1995)
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average time to hatching: 24 days.
Average eggs per season: 3.
