Haematopus bachmani

W Aleutians to central Baja Calif. and Los Coronados Islands.

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)) 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).

Length: 45 cm

Weight: 689 grams

Systems

• Terrestrial
• Marine

Depth range based on 160 specimens in 1 taxon.

Environmental ranges
  Depth range (m): 0 - 0
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

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).

Comments: Feeds on mollusks (e.g., pries open mussels and limpets), probes sand for marine worms.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: This species is represented by a large number of occurrences (subpopulations).

2500 - 10,000 individuals

Comments: Morrison et al. (2001) estimated the total population at 8,900, representing the approximate midpoint of the range 6,900-10,800 given by Andres and Falxa (1995).

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).

Maximum longevity: 16 years (wild) Observations: In the wild, these animals can live up to 16 years (http://bna.birds.cornell.edu/).

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).

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 4 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 4
Specimens with Barcodes: 6
Species With Barcodes: 1

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2008
  Least Concern
• 2004
  Least Concern

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Other Considerations: Classified as a species of "high concern" within the United States (Brown et al. 2001), Canadian (Donaldson et al. 2001), and Alaska shorebird conservation plans (Alaska Shorebird Working Group 2004). Listed as a U.S. Fish and Wildlife Service bird of conservation concern within national regions 1 and 7 (Alaska).

Global Short Term Trend: Relatively stable (=10% change)

Comments: Trend is apparently stable, but supporting data are limited. Morrison (1993/1994) categorized the population trend in Canada as "stable?"

Comments: The Black Oystercatcher's small population size and complete dependence upon a narrow coastal band throughout their life cycle make this species vulnerable to human and other mammalian disturbance (Andres and Falxa 1995). Scientific collecting, human disturbance, and mammalian predation are responsible for the extirpation of breeding pairs on small islands off the coast of Baja California (Jehl 1985). On Channel Island, California, human disturbance and feral cat predation caused breeding pairs to abandon nest sites (Warheit et al. 1984).

Oystercatchers have reestablished themselves in areas shortly after disturbance is removed. For example, 20 breeding pairs were reestablished within 5-7 years after major disturbances by humans and domesticated animals were removed on South Farallon Island, California (Ainley and Lewis 1974 in Andres and Falxa 1995). Similarly, breeding pairs increased within 7 years after lighthouse automation on Destruction Island, Washington (Nysewander 1977 in Andres and Falxa 1995). Eradication of foxes on several Aleutian islands, Alaska, resulted in recolonization by this species (Byrd 1988, Byrd et al. 1997).

Human-induced habitat alteration may have been responsible for local extirpation from islands around Sitka, Alaska, where numbers declined from 102 birds in 1940 to 4 birds in 1985 (Andres and Falxa 1995).

Biological Research Needs: Research initiatives should focus on factors affecting productivity in different areas throughout the range, with an emphasis on nest and chick survival (Murphy and Mabee 1999). Research is also needed on wintering ecology, including identification of wintering concentrations and migratory behavior. Effects of shoreline development and disturbance need study.

Stewardship Overview: Due to species' limited population size, habitats hosting high densities of oystercatchers during breeding, stopover/staging, and wintering periods should be protected from disturbance. About 7% of the worlds and 36-48% of southcentral Alaska's Black Oystercatcher population resides on Middleton Island during summer (Gill et al. 2004). This island, and other important habitats like this, should be included as regional sites within the Western Hemisphere Shorebird Reserve Network (WHSRN; Gill et al. 2004). Identify habitats prone to land development activities and human disturbance and develop mitigation prescriptions to reduce negative influences on them (Andres and Gill 2000, Alaska Shorebird Working Group 2004). During the non-breeding season, buffer zones that reduce human and boat traffic in sensitive areas should be established around feeding and roosting concentrations (Andres and Falxa 1995).

This species forages exclusively on marine invertebrates and other marine food items. Water quality in feeding areas to ensure healthy prey populations is also an important conservation issue. In areas at risk to large scale environmental perturbations, such as oil spills, baseline information should be collected on breeding density and productivity, prey abundance and quality, and size of non-breeding populations (Andres and Falxa 1995).