American Oystercatcher, Haematopus palliates

American Oystercatcher, Haematopus palliates frazari. Photograph taken in the coastal area of Yavaros, Sonora, January 2018. Photograph and identification courtesy of David F Smith, Alamos, Sonora.

American Oystercatcher, Haematopus palliates frazari. Photograph taken in coastal Agua Verde, Baja California Sur, March 2020. Photograph and identification courtesy of Barry Mastro, Escondido, California.

American Oystercatcher, Haematopus palliates frazari. Photograph taken within the rocky shoreline of the greater Bahía de los Ángeles area, Baja California, November 2008. Photograph courtesy of George Flicker, Bahía de los Ángeles. Identification courtesy of Mary & George Flicker, Bahía de los Ángeles.

American Oystercatcher, Haematopus palliates frazari, Hybrid with the Black Oystercatcher, Haematopus bachmani. Photograph taken within the rocky shoreline of the greater Bahía de los Ángeles area, Baja California, January 2022. Photograph courtesy of George Flicker, Bahía de los Ángeles. Identification courtesy of Mary & George Flicker, Bahía de los Ángeles.

American Oystercatcher, Haematopus palliates palliatus. Photographs taken off the beach in Longboat Key, Florida, January 2012. Photographs courtesy of Carol Snow, Del Mar, California.

The American Oystercatcher, Haematopus palliates frazari and Haematopus palliates palliatus, are two of the five subspecies of American Oystercatcher, and the two are found in Mexico. They are a member of the Haematopodidae Family of Oystercatchers, which has twelve global species all placed in the Haematopus Genera. They are one of the most easily recognized birds in North America. They are known in Mexico as ostrero pío Americano.

The American Oystercatcher is a large, conspicuous shorebird, common in coastal salt marshes and along sand beaches. The sexes are similar in appearance. They have a very dark head and neck with a contrasting brown mantle, a white breast, and flanks. Their bill is long, laterally compressed, straight, and bright red to orange in color, their eyes have a bright yellow iris with a red ring, and their legs are pink and long.

The American Oystercatcher is found almost exclusively in areas that have an abundance of food including intertidal sand or mud flats, oyster beds, reefs, and shell rakes that are near roosting areas that have open ground without vegetation including beaches, dunes, or marsh islands. They are diurnal predators that feed along the edge of receding tides on sand or mud flats or in submerged mussel and oyster beds. Their diet is almost exclusively bivalves, crustaceans, mollusks, worms, and other marine invertebrates. They nest on sand and shell beaches, dunes, and salt marshes that lack vegetation. Their nests are subject to human disturbance and predation by numerous birds, bobcats, cats, coyotes, crabs, domestic dogs, mink, rats, red fox, skunks, and to flooding. They have life spans of up to seventeen years.

The American Oystercatcher is found in all coastal regions of Mexico including numerous off-shore islands. They are partial migrators with the southern populations being year-round residents and the northern populations making annual winter migrations to warmer climates. First-year birds over-summer for at least one year before returning to the breeding grounds in the second, third, or fourth year. The frazari subspecies are found in western Mexico from Baja California south to the Isthmus of Tehuantepec. There are documented breeding populations in the states of Sinaloa and Baja California Sur. The palliatus subspecies is found along the entire coastline of the Gulf of Mexico and the Caribbean, and the Pacific coast south of the Isthmus of Tehuantepec. There are documented breeding populations on the northern coast of the Yucatán Peninsula.

The American Oystercatcher is distinctive and not easily confused with any other species. However, the frazeri subspecies is known to hybridize with the Black Oystercatcher, Haematopus bachmani, and the hybrid has black flecking or mottling on its upper breast and can be difficult to distinguish from the pure Americans Oystercatcher.

From a conservation perspective, the American Oystercatcher is categorized by the IUCN as of Least Concern with stable, widely distributed populations. However, their long-term viability is threatened by loss of habitat by coastal development, human disturbance, predation, water quality erosion due to pollution, and global climate change that would cause rising sea levels and eliminate the small isolated islands that they utilize for nesting and roosting.