Northern Prairie Wildlife Research Center
We combined results from Austin (1988) for telemetry (% of time spent in moist-soil areas/day) and time-activity budgets (% of time spent feeding) to indicate seasonal differences in the average proportion of a day spent feeding in 6 main habitats (Fig. 1). In late fall, geese spent a larger proportion of the day feeding in wetlands than in agricultural crops. In late winter, most feeding activity occurred in wetlands and pastures. In spring, geese spent 14% of the day feeding in harvested soybean fields and 7% in wetlands, whereas other habitats were used for feeding <3% of the day. Differences in foraging efficiency among habitat types probably is an important factor, but we lack information on feeding efficiency of geese in different habitats and under varying environmental conditions.
Time-activity budgets (Austin 1988) also indicated seasonal shifts in how wetland foods were exploited (Fig. 2). Geese fed primarily on the water surface in fall, and by spring spent an increasing portion of foraging time grubbing in shallow puddles or muddy areas. In wetlands where water had been withdrawn, foraging on vegetation was highest in early fall, and digging increased in late winter and spring. These patterns represented a shift from green vegetation and seeds in fall and winter to tubers and rhizomes in spring. Seasonal changes in feeding mode and food selection in wetlands probably are influenced also by foraging efficiency and food availability.
McKenzie (1987) monitored waterfowl use of 8 moist-soil units on Mingo NWR in southeastern Missouri from November through March, 1985-86. Both ducks and Canada geese responded rapidly to flooding of moist-soil units in fall; ducks consumed primarily seeds of moist-soil plants while geese consumed mostly browse and rootstocks. Goose use of moist-soil units was ≥2 times higher than mallard use before freeze-up. More than 50,000 goose use-days were recorded on the 8 units during the winter; peak use (11,600 use-days/week) occurred in early January, and 75% of the total goose use-days occurred during the second half of the winter. Waterfowl use of the units was hampered by rank vegetation and ice cover (McKenzie 1987).
Investigations of goose and duck use of managed moist-soil units at Mingo NWR are continuing (M. K. Lauban and L. H. Fredrickson, Univ. of Mo., unpubl. data) . During 1989-90, dry conditions in the region concentrated waterfowl on the refuge. Use of moist-soil units proximate to upland fields increased as upland wheat, clover, and other foods were depleted. Use occurred both before flooding (fall) and following inundation (winter-spring). Foods available to geese varied somewhat among the managed units, but buttonweed (Diodia virginiana), chufa (Cyperus esculentus), and millet (primarily barnyard grass, Echinochloa muricata) were common in all units and their roots or seeds were used by geese. Overall, the 382 ha of moist-soil provided over 1.3 million use-days for geese and over 1 million use-days for ducks.
Large-bodied Canada geese (i.e., B. c. maxima and B. c. interior) respond well to moist-soil habitats in Missouri. Favored habitats seem to be associated with plants having large seeds such as millets and smartweeds (Polygonum spp.), good production of underground biomass such as chufa and arrowhead (Sagittaria spp.), or browse such as blunt spikerush (Eleocharis obtusa).