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Charadrius alexandrinus - Snowy Plover

Snowy Plover image

Geographic range:

West and East coast of US in summer, Pacific and Gulf Coast into Mexico and Caribbean in winter.

Key features:

Light and drab crown, nape, face, and neck patches (like the back) and a white chest and belly.

Habitat(s):

bay (sandy shore), estuary, exposed sandy beaches, protected sandy beaches
 

Primary common name:

Snowy Plover

General grouping:

Seabirds and shorebirds

ITIS code:

176510
 

Geographic Range

Range Description:

In North America, Charadrius alexandrinus can be found along the Gulf Coast from Florida through Mexico and along the Pacific Coast from Washington to southern Mexico as well as at inland locations across the western United States. This plover is also found in the Caribbean, along the Pacific Coast of South America, in northern Africa and across Eurasia.

Habitats

bay (sandy shore), estuary, exposed sandy beaches, protected sandy beaches

Habitat notes:

Charadrius alexandrinus inhabits sandy beaches and mud flats. They can also be found on sand dunes, coastal lagoons, salt flats, sandy river edges, shallow alkaline lakes or ponds and reservoirs.

Abundance

Relative abundance:

Charadrius alexandrinus is uncommon and declining, especially in the Gulf Coast.

Species Description

General description:

Charadrius alexandrinus is the smallest and whitest of the plovers within North America. It belongs to the Plover family Charadriidae in the order Charadriiformes in the class Aves.

Distinctive features:

Charadrius alexandrinus is a small and pale plover which allows it to blend in well with its sandy environment. Its back is pale tan and its underparts are white. The bill is thin, short and dark, the eyes are brown and the legs are dark or grayish. Breeding males exhibit black patches on ears and on the sides of the breast. In breeding females, these patches are browner than black and in juveniles and non-breeding adults the side and ear patches are pale.

Female and juvenile Charadrius alexandrinus may resemble the Piping Plover, Charadrius melodus, but can be distinguished by the thinner bill and darker legs. Also Charadrius melodus has a more rounded profile, thicker chest band and shows a white band across the top of its tail in flight. The Killdeer, Charadrius vociferus, can resemble Charadrius alexandrinus, but is differentiated by its larger size and its two distinct chest bands. The Wilsonís Plover, Charadrius wilsonia, can be distinguished from Charadrius alexandrinus by its larger size, darker plumage on the back, its thick, complete chestband and its large, thick bill. The Semipalmated Plover, Charadrius semipalmatus, can be differentiated from Charadrius alexandrinus by its darker back, yellowish legs, short and thick bill and its more rounded profile.

Size:

Charadrius alexandrinus can grow to a size of 17 cm with a wingspan of 34 cm and a weight of 58 g.

Natural History

General natural history:

Charadrius alexandrinus is a social bird in the winter and may form flocks of up to 300 individuals. Nesting birds may also gather at dusk to socialize while bathing, drinking and feeding. When sleeping, these birds tuck their bill and the front of their head under their feathers and stand on one leg. Both male and female Charadrius alexandrinus actively defend their nests and breeding territories from other plovers by posturing, chasing or fighting. The males are usually more aggressive than females and fights frequently occur between them. If a predator approaches on the other hand, they usually run from their nest.

Populations of Charadrius alexandrinus have been seriously declining over the years due to recreational overuse of beaches, habitat loss from beach front development and predation, especially by red foxes. Since their nests are mere scrapes in the sand, they go unseen or ignored by the masses of people sunbathing, hiking or driving off road vehicles. Birds flee their nests when disturbed and may not return for hours, at which time their eggs may have been crushed, eaten, or overheated in the sun. Breeding populations of Snowy Plovers along the Pacific Coast of the United States and Baja California, Mexico are listed as threatened by the U.S. Fish and Wildlife Service. Snowy Plovers are also considered threatened in Florida and Puerto Rico and considered endangered in Washington and Alabama.

Predator(s):

Eggs, chicks and adults are all threatened by predation by birds of prey and land mammals, especially the Red Fox, Vulpes vulpes. Specifically adults are also preyed upon by Merlin, Falco columbarius, Peregrine Falcon, Falco peregrinus, Prairie Falcon, Falco mexicanus, Northern Harrier, Circus cyaneus, and feral cat. Chicks and eggs are both preyed upon by Common Raven, Corvus corax, California Gull, Larus californicus, American Crow, Corvus brachyrhynchos, Fish Crow, Corvus ossifragus, Great Blue Heron, Ardea herodias, opossum and ghost crab, Ocypode sp.. Chicks are also preyed upon by Loggerhead Shrike, Lanius ludovicianus, American Kestrel, Falco sparverius, Northern Harrier, and Cattle Egret, Bubulcus ibis. Eggs are additionally preyed upon by Ring-billed Gull, Larus delawarensis, Coyote, Canis latrans, Gray Fox, Urocyon cinereoargenteus, Island Fox, Urocyon littoralis, striped skunk, Mephitis sp., spotted skunk, Spilogale sp., and Raccoon, Procyon lotor.

Prey:

Charadrius alexandrinus feeds on aquatic and terrestrial invertebrates. On the Pacific Coast of North America, these include mole crabs, Emerita sp., polychaetes, amphipods, sand hoppers, tanadacians, flies, beetles, clams, and ostracods.

Feeding behavior

Carnivore

Feeding behavior notes:

Charadrius alexandrinus forages by pausing, looking, running and then seizing their prey from the surface of the beach, tide flat, or lakeshore. They may also probe in the sand or lower their head and charge a group of insects.

March - October

Migration:

Most coastal breeders are permanent residents, while most inland breeders migrate to the coast in the winter. On the Pacific Coast of the United States, migrants arrive approximately in early March and leave from late June to late October depending on location.

January - July

Reproduction:

Charadrius alexandrinus breeds in loose colonies on open sandy beaches. During courtship, the male constructs a shallow scrape in the ground which serves as a nest while he bows for her and flashes the white on his tail. He may also line the simple nest with shell fragments, pebbles, skeletons or vegetation.

The brooding season varies geographically with egg-laying beginning in January in Puerto Rico and March in California. The dates of the first clutch range from the middle of March until the middle of May. There may be two to three brooding seasons in places where the breeding season is long, but the last clutch will typically be laid before the middle of July. The females typically lay three eggs and both parents incubate the egg and defend their nesting territory. The incubation period is usually 26 Ė 32 days. The chicks leave the nest and begin feeding themselves within hours of hatching, but stay within parental care until they can fly about 30 days after hatching. The male usually raises the young, while the female leaves within six days and finds a new mate to breed with.
Click on an image below to view a larger version in the SIMoN Photo Library. You will also be able to view important information on each photo such as photographer, date, caption and more.
Alden, P., F. Heath, R. Keen, A. Leventer, and W. Zomlefer. 2002. National Audubon Society Field Guide to California. A.A. Knopf, New York, NY.
Dunn, J.L. 1999. Birds of North America. National Geographic, Washington, D.C. 464 p.
Tague, K. 2000. Charadrius alexandrinus, Animal Diversity Web. World Wide Web electronic publication. http://animaldiversity.ummz.umich.edu, Accessed [08/29/06].
WWW
Cornell Lab of Ornithology
All About Birds
http://www.allaboutbirds.org/guide/search
Accessed 05/17/2009 for Albatross
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Accessed 01/20/2009 for Great Egret
Accessed 02/03/2009 for American White Pelican
Accessed 01/30/2009 for Pelagic Cormorant
Accessed 02/12/2009 for Black-necked Stilt
Accessed 02/28/2009 for Marbled Godwit
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Accessed 03/04/2011 for Least Sandpiper.
Accessed for California Condor

WWW
Monterey Bay Aquarium. Online Field Guide, 2008.
http://www.mbayaq.org/efc/living_species/
Accessed [04/27/06]
Accessed 01/30/2009 for Pelagic Cormorant
Accessed 8/19/09 for Bryozoan
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Accessed 8/9/09 for red octopus
Accessed 8/19/09 for Decorator crab
Accessed 7/31/09 for warty sea cucumber

WWW
Seattle Audubon Society.
http://www.seattleaudubon.org/birdweb/
Accessed 01/30/2009 for Pelagic Cormorant
Accessed 02/28/2009 for Marbled Godwit
Accessed 04/13/2009 for Heermannís Gull
Accessed 03/15/2009 for Whimbrel
Accessed 06/20/2010 for Black Turnstone
Accessed 12/15/2009 for Black-crowned Night Heron
Accessed 02/01/2011 for American Coot