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BC Conservation Data Centre: Species Summary

Haematopus bachmani
Black Oystercatcher

Scientific Name: Haematopus bachmani Audubon, 1838
English Name: Black Oystercatcher
Classification / Taxonomy
Scientific Name - Concept Reference: American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online:
Classification Level: Species
Species Group: Vertebrate Animal
Species Code: B-BLOY
Kingdom Phylum Class Order Family
Animalia Craniata Aves Charadriiformes Haematopodidae
Conservation Status / Legal Designation
Global Status: G5 (Apr 2016)
Provincial Status: S4 (Mar 2015)
BC List: Yellow
Provincial FRPA list:   
Provincial Wildlife Act:
SARA Schedule:
General Status Canada: 4 - Secure (2005)
Migratory Bird Convention Act: Y
Ecology & Life History
General Description: A relatively large, all-black shorebird, with a heavy, bright-red bill typical of oystercatchers. Bright yellow iris with orange-red orbital ring in adults; sturdy, pale pink legs. Females have longer, narrower bills and heavier bodies (Andres and Falxa 1995).
Global Reproduction Comments: Eggs laid late May-early July (generally early to mid-June) in Alaska, mid-May to late June (generally mid-June) in Washington/Oregon, early May-late June (generally late May) in southern California (L'Hyver and Miller 1991). Clutch size 1-4 (usually 2-3). Incubation 26-27 days, by both sexes. Nestlings precocial but dependent on parental feeding for several weeks (both sexes feed young). Chicks begin to fly at 35+ days. Long-term mate fidelity. See Terres (1980), Groves (1984), Purdy and Miller (1988).
Global Ecology Comments: Winter flocks seldom range more than 30 miles from nesting sites (Terres 1980), except in northern populations (Andres and Falxa 1995). Obligate users of intertidal zone year-round. Period from hatching until time of first flight is critical life-history stage (Groves 1984).
Migration Characteristics:
(Global / Provincial)
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant:
Y /
N /
N /
na /
Global Migration Comments: Although birds in the southern portion of the range generally remain near nesting areas throughout the year, individuals in northern populations probably undertake migrations (Andres and Falxa 1995), although little is understood about their seasonal movements. Over 75% of Black Oystercatchers breeding in Prince William Sound, Alaska, migrate out of the sound to spend the winter, although their wintering destination is unknown (Andres 1998). Small flocks, usually less than 25 birds, have been recorded migrating in spring and fall along the outer coast of Alaska (Andres and Falxa 1995).

In Alaska, flocks that consist of nonbreeders and failed breeders increase in size throughout July and August and depart in September (Andres and Falxa 1995). In British Columbia, flocks build throughout September and October, reaching peak numbers in late October, early November (Campbell et al. 1990). Spring movements probably occur during March; birds reoccupy vacated territories during March and April (Purdy 1985, Andres and Falxa 1995). One individual, banded at Bodega Bay, CA, was sighted 340 km to the north in July, and then returned to banding site in September (Falxa 1992, Andres and Falxa 1995).
(Type / Subtype / Dependence)
Global Habitat Comments: Breeding: Habitat is exclusively associated with the high tide margin of the inter-tidal zone, and includes mixed sand and gravel beaches, cobble and gravel beaches, exposed rocky headlands, rocky islets, and tidewater glacial moraines. The southern limit of their range coincides with a change of rocky shores to sandy beaches (Jehl 1985). Breeding territories are usually in close proximity to dense mussel beds. Avoids brushy and forested habitats. Breeding density is generally greatest on non-forested islands and islets. Nest is a shallow circular depression on the ground (e.g., scrape on beach of broken shell) or on a rock (Groves 1984). The retreat of glaciers, which expose gravel moraines, and uplift from earthquakes can create new oystercatcher nesting habitat (Lentfer and Maier 1995, Gill et al. 2004).

Non-breeding: In winter, flocks concentrate on protected, ice-free tidal flats with dense mussel beds (Hartwick and Blaylock 1979).
Food Habits: Invertivore: Adult, Immature
Global Food Habits Comments: Feeds on mollusks (e.g., pries open mussels and limpets), probes sand for marine worms.
Global Phenology: Diurnal: Adult, Immature
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: N
Length(cm)/width(cm)/Weight(g): 45/ / 689
Elevation (m) (min / max): Global: 
Endemic: N
Global Range Comment: Resident along Pacific Coast from Kiska Island, Aleutians, Alaska, south to Baja California, Mexico. Most breed between south-coastal Alaska and coastal British Columbia (Andres and Falxa 1995, Morrison et al. 2001).
Authors / Contributors
Global Information Author: Gotthardt, T. A., and G. Hammerson. Rev. by David Tessler, Alaska Dept. Fish and Game
Last Updated: Feb 22, 2006
Provincial Information Author:
Last Updated:
References and Related Literature
Alaska Shorebird Group. 2004. Alaska shorebird conservation plan. U.S. Shorebird Conservation Plan. Unpublished report. 2nd Edition. Prepared by: Alaska Shorebird Working Group. March 2004. Available through U.S. Fish and Wildlife Service, Migratory Bird Management, Anchorage, AK.
American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.
Andres, B. A., and G. A. Falxa. 1995. Black Oystercatcher (Haematopus bachmani). The Birds of North America No. 155 (A. Poole and F. Gill, editors). Academy of Natural Sciences, Philadelphia, PA, and American Ornithologists' Union, Washington, DC. 20pp.
Andres, B. and R. Gill (eds.). 2000. A conservation plan for Alaska shorebirds. Unpublished report. Alaska Shorebird Working Group. Available through U.S. Fish and Wildlife Service, Migratory Bird Management, (Contact Anchorage, Alaska. 47 pp.
Andres, B.A. 1998. Black oystercatcher (Haematopus bachmani). Exxon Valdez Oil Spill Trustee Council Restoration Notebook. 8 pp.
Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, J.M. Cooper, G.W. Kaiser, and M.C.E. McNall. 1990b. The Birds of British Columbia Vol. 2: Nonpasserines: Diurnal Birds of Prey through Woodpeckers. Royal British Columbia Museum, Victoria, BC.
Carter, M., C. Hunter, D. Pashley, and D. Petit. 1998. The Watch List. Bird Conservation, Summer 1998:10.
Carter, M., G. Fenwick, C. Hunter, D. Pashley, D. Petit, J. Price, and J. Trapp. 1996. Watchlist 1996: For the future. Field Notes 50(3):238-240.
Falxa, G.A. 1992. Prey choice and habitat use by foraging black oystercatchers: interactions between prey quality, habitat availability, and age of bird. Ph.D. diss., Univ. of Calif., Davis.
Groves, S. 1984. Chick growth, sibling rivalry, and chick production in American black oystercatchers. Auk 101:525-531.
Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.
Hartwick, E.B. and W. Blaylock. 1979. Winter ecology of a black oystercatcher population. Stud. Avian Biol. 2:207-215.
Jehl, J. R., Jr. 1985. Hybridization and evolution of oystercatchers on the Pacific Coast of Baja California. Ornithological Monographs 36:484-504.
L'Hyver, M.-A., and E. H. Miller. 1991. Geographic and local variation in nesting phenology and clutch size of the black oystercatcher. Condor 93:892-903.
Lentfer, H.P., and A.J. Maier. 1995. Breeding ecology of the black oystercatcher in the Beardslee Island region of Glacier Bay National Park. Pages 267-269 in D.R. Engstrom (Ed.). Proc. Third Glacier Bay Sci. Sym., 1993, Natl. Park Service, Anchorage, AK.
Morrison, R. I. G., R. E. Gill, Jr., B. A. Harrington, S. Skagen, G. W. Page, C. L. Gratto-Trevor, and S. M. Haig. 2001. Estimates of shorebird populations in North America. Occasional Paper Number 104, Canadian Wildlife Service, Environment Canada, Ottawa, ON. 64 pages.
Purdy, M. A., and E. H. Miller. 1988. Time budget and parental behavior of breeding American black oystercatchers (Haematopus bachmani) in British Columbia. Can. J. Zool. 66:1742-1751.
Purdy, M.A. 1985. Parental behavior and role differentiation in the black oystercatcher Haematopus bachmani. M.S. Thesis, University of Victoria, Victoria, British Columbia. 237 pp.
Sibley, C.G., and B.L. Monroe, Jr. 1990. Distribution and Taxonomy of Birds of the World. Yale University Press, New Haven, CT. xxiv + 1111 pp.
Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 2006. Species Summary: Haematopus bachmani. B.C. Minist. of Environment. Available: (accessed Feb 6, 2023).