Branta canadensis occidentalis

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Transient

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

SW Alaska (Prince William Sound to Copper River Delta).

Occurs (regularly, as a native taxon) in multiple nations, but breeds in a single state or province

Global Range: (<100-250 square km (less than about 40-100 square miles)) Breeding occurs on the Copper River Delta near Cordova, Alaska, including Egg Island, Castle Island, and Storey Island. Nonbreeding and molting geese occur in the Bering Glacier area (Eldridge et al. 1997). Wintering occurs primarily in the Willamette Valley of Oregon and along the Columbia River in Washington (Bartonek et al. 1971, Cornely et al. 1988).

Comments: Breeds in freshwater marsh with tall shrub vegetative cover. Landscape level: herb graminoid and mixed tree/shrubs landcover classes dominated all 5 breeding-pair density strata (Crouse et al. 1996). Nest site level: Interlevee basins were the most common site used for nesting, followed by levees (Crouse et al. 1996). Low shrub cover or low height forb cover were important components of a nest site in high density nesting strata (Crouse et al. 1996).

Winters in farm fields and agricultural wetlands in Washington and Oregon (Bromley 1976, Cline and Lenhart 1985, Campbell 1990).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

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.

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

Estimated Number of Occurrences: 1 - 5

Comments: At the landscape level, one breeding location (Copper River delta) exists in Alaska. Approximately 15 wintering locations occur in the Willamette Valley, Oregon, and in southern Washington (Pacific Flyway Council 1997).

10,000 - 100,000 individuals

Comments: Population has fluctuated from lows during the mid-1950s (~5,000 birds) to highs during the 1970s (~20,000 to 25,000 birds) (Cornely et al. 1985, Bromley and Rothe 2003). Population estimates during the 1990s ranged from 12,000 to 14,000 individuals (Pacific Flyway Council 1997, Bromley and Rothe 2003).

Canada

Rounded National Status Rank: N2M - Imperiled

United States

Rounded National Status Rank: N2B,N2N : N2B: Imperiled - Breeding, N2N: Imperiled - Nonbreeding

Rounded Global Status Rank: T3 - Vulnerable

Reasons: Breeding pairs on the Copper River Delta appear to have declined slightly from 1986 to 1997 (slope coefficient = 0.971, Eldridge et al. 1997). Highly variable young production--from 3.9% to 23.5% young of the year ratios-- on the Copper River Delta in July during the last 14 years (Pacific Flyway Council 1997). Primary concern is the highly restricted areas of breeding, migration stop-overs, and wintering areas across this subspecies' year round range (Pacific Flyway Council Earthquake-caused successional changes in vegetation have promoted increased access by predators and thus increased predation (Campbell 1990). Poor nesting success due to predation is a significant threat to the long-term persistence of this population (Pacific Flyway Council 1997). Loss of habitat outside of protected refuges within the wintering range and migration route is also a potential threat (Pacific Flyway Council 1997).

Global Short Term Trend: Unknown

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: Natural successional changes in the Copper River Delta (CRD), accelerated by the uplift following the 1964 earthquake, have led to an increasing number and diversity of goose, nestling, and egg predators, including brown bears, coyotes, wolves, red fox, river otter, mink, bald eagle, gulls, and jaegers (Campbell 1990). Loss of habitat outside of refuges on wintering grounds and along migration routes is a potential threat. Particular concern is the conversion of bottomland pastures along the Columbia and Willamette Rivers to development interests, including cottonwood plantations (Pacific Flyway Council 1997). Loss of this habitat would reduce the total amount of potential wintering habitat, resulting in geese concentrating on protected lands and potentially increasing crop depredation. Political pressure for controlling increasing crop depredation, primarily due to increases of Cackling Canada Geese (B. c. minima), which winters in the same area, may weaken current stringent harvest protections. Petroleum and coal field development, as well as associated road development in the Bering Glacier area may detrimentally affect nonbreeders and molting geese, as well as some breeders in the area (Bartonek et al. 1971).

Overhunting on the winter range was a problem in the late 1970s and early 1980s but hunting is presently not limiting the population (Pacific Flyway Council 1997, Bromley and Rothe 2003). For example, restrictive harvest regulations, redirected harvest management, and required goose identification classes in Washington and Oregon reduced Dusky Geese harvest to 1% of the total Canada Goose harvest in Washington and Oregon wintering area in 1996 (Pacific Flyway Council 1997).

Management Research Needs: The U.S. Fish and Wildlife Service would like to develop a breeding ground population estimate that could account for renesting and a visibility correction factor to provide the best estimate of the Dusky Canada Goose population (Pacific Flyway Council 1997).

Biological Research Needs: The following research needs were highlighted in the Pacific Flyway Management Plan for the Dusky Canada Goose (1997): 1) Conduct a study of genetic relations among Dusky Canada Geese and other Canada Geese populations from Cook Inlet, Alaska, to Oregon (ongoing, see Scribner et al. 1997). 2) Study late-nesting and predation on the CRD to determine renesting frequency, agents of nest and brood losses, and brood period mortality. 3) Inititate a satellite/radio telemetry study to determine breeding distribution, fall and spring migration staging areas, and timing of migration. 4) Determine survival rates and sources of mortality for adult geese during the nesting period. 5) Determine visibility correction factors for breeding pair and production surveys using radio-marked male and female Dusky Canada Geese on the CRD. 6) Evaluate movements and brood rearing success of females nesting on Egg Island using radio telemetry. 7) Estimate numbers and productivity of Canada geese breeding in Prince William Sound including Green, Hinchinbrook, and Montague Islands. 8) Estimate nesting propensity and success of 2- vs. 3 year old females using known-aged females. 9) As an alternate to other methods, estimate recruitment on the CRD and elsewhere using DNA isolated from eggshell membranes.

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: This subspecies is protected under the Migratory Bird Treaty between the United States and Canada. Regulated harvest occurs in Alaska, Oregon, and Washington. Wintering grounds are mostly on wildlife refuges and state wildlife areas. Primary wintering areas include: Willapa Bay National Wildlife Refuge (NWF), Lewis and Clark NWR, JBH NWR, Ridgefield NWR, Sauvie Island State Wildlife Mangagement Area, Tualatin NWR, Basket Slough NWR, Ankeny NWR, Finley NWR, and the Fern Ridge Reservoir (Pacific Flyway Council 1997). See also management information.

Needs: Maintain appropriate regulation of harvest in Alaska, British Columbia, Washington, and Oregon. Secure protection for Bering Glacier molting area from development impacts. Secure permanent protection for the population of breeding Canada geese on Middleton Island. Implement a conservation promotion strategy with land owners in Washington and Oregon to promote regional conservation of lands important to wintering geese, possibly through monetary or tax burden relief compensation.

Stewardship Overview: Cooperative management by the Pacific Flyway Council has resulted in adoption of a management plan addressing population trends, threats, protection, and inventory and research needs (Pacific Flyway Council 1997). Members of the council represent wildlife agencies from Alaska, British Columbia, Washington, and Oregon (Pacific Flyway Council 1997). The Pacific Flyway Management Plan for Dusky Canada Geese identifies three "Action Levels", intended to maintain and enhance the number of Dusky Canada Geese on the Copper River Delta, and thus the total population. Levels are triggered by the mid-winter population annual index if the population is declining and by a 3-year average of the mid-winter population index if the population is increasing. These action levels are: 1) 8,000 total birds or above, 2) 6,500 to 8,000 birds, 3) below 6,500 birds. Specific management actions are described in the plan for each action level relating to breeding grounds, migration areas, wintering grounds, public use, crop depredation control, inventories, and research (Pacific Flyway Council 1997). If action level three is reached, the agencies included in this management plan will initiate a thorough population viability analysis, review the conservation status of Dusky Canada Geese, and reassess all feasible and pracical intensive management options (Pacific Flyway Council 1997).