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A stochastic simulation model designed to test alternative management schemes on refuging waterfowl populations was constructed from data on fall-migrating snow geese (Chen caerulescens) at the DeSoto National Wildlife Refuge. Components of the model include population level, food density and distribution, food-searching flight characteristics, feeding rates, activity and energy budgets, migration rates, and effects of weather, hunting pressure, and land management practices on the system. Data were collected to test the model's validity. Refuge population level was not sensitive to shifts (±20%) in the input values of 25 selected parameters, but hunting mortality and daily foraging distances were sensitive to several combinations of parameter perturbations. Model outcome was most sensitive to changes in digestive efficiency, mean food density, and the proportion of refuge fields in which food was available. In other model experiments, increased hunting pressure caused significant (P < 0.05) increases in hunting mortality and a reduction in the refuge population. The effect of hunting was less important in reducing waterfowl population size than the associated disturbance of feeding snow geese by hunters.