Restoration Lake Research
Habitat Restoration and Canvasback Status

Objectives

To determine the status of canvasback populations and diving duck migrational habitats in Wisconsin and to evaluate rehabilitation and restoration techniques for aquatic ecosystems used as migrational habitats by diving ducks.

Background

Traditional canvasback staging sites on upper Midwest lakes have received declining use since the 1960s. Use of the upper Mississippi River has increased during this same period. Siltation, eutrophication, pollution, rough fish, and disturbance potentially contribute to the degradation of this former migrational habitat. The apparent dependence of canvasbacks on the upper Mississippi River causes concern, as any deterioration of that aquatic ecosystem will affect a large portion of the North American population.

The availability of preferred foods such as wildcelery and fennel-leaf pondweed determine fall concentration sites and migrational routes. Canvasbacks may consume macrobenthic food items (e.g., small clams) in a few locations where wildcelery and fennel-leaf pondweed are unavailable. Well-distributed staging areas with essential food items are necessary for maintaining migrational integrity between breeding and wintering sites.

Improving or restoring migrational habitat at former staging sites or developing new sites could dramatically shift the fall distribution of migrating canvasbacks and ease concerns regarding heavy dependence on the few remaining suitable areas. Although canvasbacks are the target species for habitat development, other diving ducks--particularly the redhead--and other non-bird species (including humans) would benefit from the improved or restored aquatic ecosystem.

For more information on this topic please contact:
Richard Kahl (608)221-6358