The Role of the
Willamette Valley Refuges
in Wintering Canada Geese Habitat

Ankeny, Baskett Slough, and W. L. Finley NWRs were established in the mid 1960s with primary purposes being to provide winter habitat for dusky Canada geese and other migratory waterfowl. At that time, approximately 18,000 Canada geese wintered in the Willamette Valley and lower Columbia River floodplain (WV-LCR), nearly all of them identified as duskys. Since that time, the wintering goose population has dramatically increased, with total counts rising to as high as 200,000 in the year 2000 (numbers have been over 100,000 in each year since 1994 in the WV-LCR - Pacific Flyway Council, 2007).

As geese numbers multiplied, the species composition changed. The Taverner’s subspecies increased significantly in the 1970’s and more recently, during the 1990’s, cackling Canada geese shifted their distribution from California to the WV-LCR. Populations of lesser Canada geese and the resident western Canada geese have also increased. The dusky Canada goose population currently constitutes less than ten percent of the winter flock and remains below Flyway objectives.

Since establishment, the Refuges have devoted a large portion of land to ensuring an adequate supply of forage for wintering Canada geese. Forage is provided primarily by grass fields, which are planted by cooperative farmers. The geese feed heavily on this green browse during the October - April period that they spend in the Valley. Cooperative farmers then harvest the grass seed during early summer. Cooperative farming provides mutual benefits to both the farmer and the Service, and at a high degree of cost effectiveness to the Service.

The significant increase in goose numbers poses a number of inter-related challenges. At this time, the Refuges and other WV-LCR public lands are not able to meet the forage demands of this population over their wintering period. Depredation on private lands in the WV-LCR has been a concern for at least 20 years, and is the subject of a 1998 management plan prepared by the Pacific Flyway Council and other partners (Pacific Flyway Council, 1998). The primary goal of the Depredation Plan is to minimize depredation losses caused by Canada geese. To do so, the plan sets objectives to reduce the total population to 107,000 wintering geese; to increase wintering Canada goose use on public lands while subsequently decreasing use of private lands; to acquire additional public lands; and to increase goose hunting opportunities. The plan also calls for public use restrictions on public lands to decrease harassment of wintering geese. Objectives and strategies in the plan that relate to the farming program on the Willamette Valley Refuges include: increase capability to manage croplands with enhanced water supplies; experiment with alternative crops; increase fertilization, liming, and burning of grass fields; increase use of Integrated Pest Management practices and provide adequate composition of the major grass types used by Canada geese. The Refuges have implemented several changes associated with these recommendations

As wintering goose populations in the Valley have risen, geese have increased pressure on the Refuges’ grass fields, decreasing seed harvest rates. Some fields are so heavily browsed that they provide little seed to harvest. In the past, losses incurred by the Refuges’ cooperative farmers on the heavily browsed fields have been offset somewhat by profits from productive fields. Goose use of the Refuges could reach a point where the losses incurred will not be offset by profits and cooperative farming may not be economically feasible without additional support from the Service.

The three Refuges receive a substantial amount of the goose use in the Willamette Valley, but the on-Refuge carrying capacity may be at or near maximum levels now. If WV-LCR population numbers continue to rise, alternative off-refuge strategies may be the most effective way to continue to provide goose habitat while minimizing depredations on private lands. On the refuges, tradeoffs between maximizing habitat potential for dusky Canada geese and restoring or enhancing rare native habitats may need to be explicitly examined.

Key questions to be addressed in the CCP:
How much and where shall forage fields, wetlands, and sanctuary be located in order to maximize Refuge wintering populations of dusky and other Canada geese? What population targets, overall or by goose sub-species should the Refuges manage for? What additional measures, if any, should the Refuges undertake in order to maximize goose use on existing forage fields? If cooperative farming begins to prove infeasible as currently operated, what other strategies could be tried in order to maintain an efficient source of winter forage for Canada geese? What percent and array of crop types need to be provided and in what proportion? Should additional water supplies be obtained to enhance crop production?

References:

Pacific Flyway Council, 2007. Pacific Flyway management plan for the dusky Canada goose. Dusky Canada Goose Subcomm., Pacific Flyway Study Comm. [c/o USFWS], Porltnad, OR. Unpubl. Rept. Xx pp+ appendices.

Pacific Flyway Council, 1998. Pacific Flyway management plan for Northwest Oregon - Southwest Washington Canada goose agricultural depredation control. Canada goose agricultural depredation working group, Pacific Flyway Study Comm. [c/o USFWS], Portland, OR. Unpubl. Rept. 31 pp+ appendices.