Image
Ecology and Vulnerability
American Oystercatcher
Photo credit: U.S. Fish and Wildlife Service NE
Scientific name
Haematopus palliatus
Profile: American Oystercatcher ▾▸
Background
American oystercatchers are shorebirds with brown, black, and white body patterns, and distinctive long red bills. American oystercatchers are found on both coasts of North America. The...
Background
American oystercatchers are shorebirds with brown, black, and white body patterns, and distinctive long red bills. American oystercatchers are found on both coasts of North America. The east coast population breeds as far north as Cape Cod, Massachusetts and as far south as Florida, Mexico, and even the Caribbean 11. This species formerly occurred in the northeast as far north as Canada, but by the early 1900s their range decreased to Virginia 4,11 due to hunting and habitat loss. However, in recent decades, this species has expanded and reestablished former habitat in the northeast, with breeding pairs observed in Maine and Nova Scotia 2,9,13. Oystercatchers are listed as “Species of High Concern” in the U.S. Shorebird Conservation Plan 1.
In Massachusetts, American oystercatchers are found almost exclusively along salt marshes and sandy beaches on small coastal islands, and feed around intertidal areas and mud flats 8. They use their long, powerful, blade-like bills to pry open and feed on bivalves such as mussels and other hard-bodied invertebrates including barnacles, snails, and various worms 3. The shape of their bills is highly specialized based on diet, sex, and location 12. Oystercatchers are among the first migrant birds to appear on the beaches in Massachusetts in the spring, usually arriving around mid-March. Oystercatchers nest in shallow depressions on sand or dry marsh grass, and clutch sizes (number of eggs laid by a nesting pair) are usually 2-5 eggs 8. They have low survival and productivity, and are extremely vulnerable to predation, as well as nest overwash (flooding and erosion) from storm surge and severe weather 1.
Climate Impacts
Climate change will likely have negative impacts on American oystercatcher populations. Extreme high tides are a prominent threat to nest success 4,5, and as sea levels rise and storm surge increases, overwash (flooding and erosion) will continue to be a major factor influencing early life stages 7. Loss of breeding, wintering, and migration habitats are recognized as threats to oystercatcher populations, because of their high degree of habitat specialization 6. Tidal marsh and mud flat habitats are projected to decline and become increasingly fragmented under future climate change 14. There is evidence that oystercatchers are increasingly using inland river habitat for nesting, which may be an adaptive response to changing climatic conditions 10. Oystercatchers also use dredge spoil islands (islands created by the waste from dredging) for nesting and roosting, which may become an increasingly important management strategy as beach environments continue to change. Larger dredge islands with low sloping profiles, minimum vegetation, and situated close to known foraging sites have the greatest potential for increasing oystercatcher productivity 10.
References
1. Brown, S., C. Hickey, B. Harrington. and R. Gill. 2001. The U.S. Shorebird Conservation Plan, 2nd ed. Manomet Center for Conservation Sciences, Manomet, Massachusetts.
2. Brown, S.C., S. Schulte, B. Harrington, B. Winn, J. Bart, and M. Howe. 2005. Population Size and Winter Distribution of Eastern American Oystercatchers. Journal of Wildlife Management 69:1538-1545.
3. Bull, J., and J. Ferrand. 1995. National Audubon Society Field Guide of North American Birds. Alfred A. Knopf, New York. p. 470.
4. Davis, M.B., T.R. Simons, M.J. Groom, J.L. Weaver, and J.R. Cordes. 2001. The breeding status of the American oystercatcher on the east coast of North America and breeding success in North Carolina. Waterbirds 24:195–202.
5. Denmon, P., B.D. Watts, and F.M. Smith. 2013. Investigating American Oystercatcher (Haematopus palliates) Nest Failure on Fisherman Island National Wildlife Refuge, Virginia, USA. Waterbirds 36:156-165.
6. Galbraith, H., D.W. DesRochers, S. Brown, and J.M. Reed. 2014. Predicting vulnerabilities of North American shorebirds to climate change. PLoS ONE 9:e108899.
7. Manomet Center for Conservation Sciences and the National Wildlife Federation. 2014. The vulnerabilities of northeastern fish and wildlife habitats to sea level rise. A Report to the Northeastern Association of Fish and Wildlife Agencies and to the North Atlantic Landscape Conservation Cooperative. Plymouth, MA. 44 pp.
8. Mass Audubon. Breeding Bird Atlas Species: American Oystercatcher. Accessed 4/18/2016. Available at: http://www.massaudubon.org/our-conservation-work/wildlife-research-conservation/statewide-bird-monitoring/breeding-bird-atlases/bba1/find-a-bird/(id)/56
9. Mawhinney, K., B. Allen, and B. Benedict. 1999. Status of the American oystercatcher, Haematopus palliatus, on the Atlantic coast. Northeastern Naturalist 6:177–182.
10. McGowan, C.P., T.R. Simons, W. Golder, and J. Cordes. 2005. A Comparison of American Oystercatcher Reproductive Success on Barrier Beach and River Island Habitats in Coastal North Carolina. Waterbirds 28:150-155.
11. Nol, E., and R.C. Humphrey. 1994. American oystercatcher, Haematopus palliatus. Number 82 in A. Poole and F. Gill, editors. The birds of North America. The Academy of Natural Sciences, Philadelphia, Pennsylvania, USA, and The American Ornithologists’ Union, Washington, D.C., USA.
12. Pol, M.V.D., B.J. Ens, K. Oosterbeek, L. Brouwer, S. Verhulst, J.M. Tinbergen, A.L. Rutten, and M.D. Jong. 2009. Oystercatchers’ bill shapes as a proxy for diet specialization:more differentiation than meets the eye. Netherlands Ornithologists’ Union 97:335-347.
13. Post, P.W., and G.S. Raynor. 1964. Recent Range Expansion of the American Oystercatcher into New York. The Wilson Bulletin, 76:339–346.
14. Whitman, A., A. Cutko, P. De Maynadier, S. Walker, B. Vickery, S. Stockwell, and R. Houston. 2013. Climate change and biodiversity in Maine: vulnerability of habitats and priority species. Report SEI-2013-03. Manomet Center for Conservation Sciences (in collaboration with Maine Beginning with Habitat Climate Change Working Group), Brunswick, ME.
Climate Change Vulnerability Assessment: American Oystercatcher (US and Canada Atlantic Coast)
Ranking
Highly Vulnerable
Confidence
Not Specified
Climate scenario
Not Specified - Doubling of emissions
Location
US and Canada Atlantic Coast
Time period
2050
Climate Change Vulnerability Assessment: American Oystercatcher (New York)
Ranking
Moderately Vulnerable
Confidence
Very High
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
New York
Time period
2050
Climate Change Vulnerability Assessment: American Oystercatcher (Mid Atlantic Coast)
Ranking
Moderately Vulnerable
Confidence
Not Specified
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
Mid Atlantic Coast
Time period
2050
Climate Change Vulnerability Assessment: American Oystercatcher (North Atlantic Coast)
Ranking
Moderately Vulnerable
Confidence
Not Specified
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
North Atlantic Coast
Time period
2050
Climate Change Vulnerability Assessment: American Oystercatcher (Maine)
Ranking
Highly Vulnerable
Confidence
Very Confident
Climate scenario
Not Specified
Location
Maine
Time period
Not Specified