American Oystercatcher

Haematopus palliatus

(c) Sidney Maddock
  • HAEMATOPODIDAE
  • Oystercatchers
  • Charadriiformes
  • Ostrero
  • Huîtrier d'Amérique
Introduction
This large shorebird is found strictly in coastal environments, where it may be seen alone or in small groups by summer beach goers. As its name implies, it specializes in preying upon oysters and other mollusks. Unlike many shorebird species, The American Oystercatcher is a flashy bird. Its size, striking plumage, and large red bill make it particularly recognizable, especially compared to the subtle, well-camouflaged plumages of most shorebirds. 
(c) Sidney Maddock
Appearance Description

The distinctive American Oystercatcher is unlikely to be misidentified. With its highly contrasting dark and white plumage, it is among the largest of North American shorebirds, measuring up to 18 inches in length, and weighing 21 ounces, with a 32-inch wingspan. The long, flesh-colored legs, white belly, black head, and dark brown back are distinctive. Even more distinctive is the long, bright red bill. The related Black Oystercatcher occurs exclusively on the west coast; as the name suggests, it is completely black.

Range Map
Courtesy Kenn Kaufman
Range Distribution
On the Atlantic coast, the American Oystercatcher generally breeds from Florida to Massachusetts. It is found year-round at various points around the Gulf Coast and Caribbean. In South America, it occurs as far south as Argentina on the Atlantic Coast, and Chile on the Pacific. In Mexico and Central America, it is found locally on both coasts, breeding as far north as Baja California.. Only about 12 percent of the species' global population occurs within the United States. Up to one third of the U.S. population is thought to winter in South Carolina alone.
 
A legend for the range map to the right can be found here.
Habitat
The strictly coastal American Oystercatcher prefers vast open areas of sandy dunes and tidal marshes. The birds often nest just above the high tide mark on sandy or rocky beaches with little vegetation, and feed in areas exposed by the receding tide, such as sandbars or shellfish beds. Secluded barrier or dredge spoil islands are often favored for nesting.
Feeding
At low tide, oystercatchers can be found wading about in exposed beds of oysters, clams, or other mollusks, or at intertidal areas, probing the mud for food. When a shellfish is found, the oystercatcher deftly employs it long bill, inserting it knife-like between the valves of it prey, which is pried open and quickly consumed. The bill can also function more like a hammer, useful for pummeling sealed shellfish until they break apart. While bivalves such as oysters or clams are its main food source, the American Oystercatcher feeds opportunistically on prey such as shrimp, crabs, jellyfish, worms, insects, or even small fish.
Reproduction

In early spring, American Oystercatcher pairs select an elevated nest site beyond the high tide mark, generally with a full view of their surroundings. Together, the male and female construct a crude nest on the ground, where up to four eggs are laid. In areas of high nesting density, oystercatchers sometimes employ an atypical communal breeding strategy. One male and two females tend up to six eggs cooperatively, often in two nests. In either case, parents incubate the eggs for about four weeks. The semi-precocial chicks are led from the nest quickly. Unlike the young of most shorebirds, however, they cannot feed themselves right away, but rely primarily on their parents for food for up to eight weeks. Once independent, young American Oystercatchers flock together. While immature birds sometimes form pairs, they do not breed until at least their third year. Pairs may last for life.

Migration
Range wide, most American Oystercatcher populations are thought to be non-migratory. However, nearly all birds from New England to Maryland move south for the winter, generally departing by late September. The largest wintering Atlantic coast concentrations occur from Virginia through the Carolinas. The details of migration remain a mystery within Central and South America.
  • 72,000
  • 8,850
  • Very small population; high threats year-round
Population Status Trends
In the 19th and early 20th centuries, egg collecting, hunting, and other human intrusions drove this shy yet conspicuous species to the brink of extirpation in North American. Passage of 1918's Migratory Bird Treaty Act afforded the birds a certain degree of protection, but by this time, its range had contracted significantly. Official protection, coupled with notable conservation efforts such as the establishment of coastal wildlife refuges, fostered a slow return to its former range.
 
By the 1950s, the American Oystercatcher had returned to Maryland and New Jersey. By the early 1970s, it had returned to New York, and was firmly established in Massachusetts by decade's end. More recently, it has bred as far north as Maine. The historic northern extent of the species' breeding range remains unclear. In 1835, John James Audubon recorded breeding as far north as Labrador, but such reports are unsubstantiated. How much further the American Oystercatcher's range will expand in the northeast remains to be seen.
 
While both the range and number of the American Oystercatchers are increasing somewhat, Audubon's WatchList in 2002 classified the species as "Yellow" (of national conservation concern). The species' relatively low population, coupled with formidable range-wide threats to its habitat, makes it particularly susceptible to loss. At fewer than 9,000 birds, the North American population is well below historic levels.
Conservation Issues
The Migratory Bird Treaty Act of 1918 and more recently, the establishment of National Wildlife Refuges and Audubon Important Bird Areas within key portions of the birds' range have greatly benefited American Oystercatchers. Audubon Coastal Island Sanctuary systems provide thousands of acres of safe habitat, particularly in North Carolina and along the Texas Gulf Coast. Audubon's Coastal Bird Conservation Program is working with partners throughout its Gulf and Atlantic range to survey and protect this species during the breeding season. This strictly coastal species is greatly impacted by marine habitat loss, so further protection of remaining pristine coastal habitat is essential.
 
Despite its expanding range, the American Oystercatcher is currently listed as a Species of Special Concern in many coastal states. Due to its small North American population and concentrated winter range, the American Oystercatcher is particularly vulnerable to catastrophe; one hurricane or oil spill could prove devastating. Oystercatchers are shy birds, so human encroachment—particularly on the breeding grounds—is another serious threat. The species has benefited from at least one human activity—the creation of dredge spoil islands in many coastal areas. Oystercatchers find such altered areas ideal for nesting, and dredging has contributed to the American Oystercatcher's return to its former breeding range.
What You Can Do
Stay clear of nesting American Oystercatchers. These birds are quite shy, and highly susceptible to human disturbance. Bird watchers, photographers, and outdoor enthusiasts should avoid disturbing this at-risk species.
 
For actions you can take, including Audubon activities, please visit our resources page.
More Information
Visit our resources page for more information about this species.
Natural History References
Bent, A. C. Life Histories of North American Shorebirds. U.S. National Museum Bulletin 146. 1929.

Kaufman, Kenn. 1996. Lives of North American Birds. Houghton Mifflin Company, New York.

Nol, E. and R. C. Humphrey. 1994. American Oystercatcher (Haematopus palliatus). In The Birds of North America, No. 82 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
 
Richards, Alan. Shorebirds: A Complete Guide to Their Behavior and Migration. Gallery Books, New York. 1988.
 

Sanders, F., and Murphy, T. 2004. American Oystercatcher. South Carolina Department of Natural Resources.

Conservation Status References
Bent, A. C. Life Histories of North American Shorebirds. U.S. National Museum Bulletin 146. 1929.

Kaufman, Kenn. 1996. Lives of North American Birds. Houghton Mifflin Company, New York.

Nol, E. and R. C. Humphrey. 1994. American Oystercatcher (Haematopus palliatus). In The Birds of North America, No. 82 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
 
Richards, Alan. Shorebirds: A Complete Guide to Their Behavior and Migration. Gallery Books, New York. 1988.
 
Sanders, F., and Murphy, T. 2004. American Oystercatcher. South Carolina Department of Natural Resources.