Autumn Diet of Lesser Snow Geese Staging in Northeastern Alaska

Brackney, Alan; Hupp, Jerry

The coastal plain of the Arctic National Wildlife Refuge (ANWR) is used by lesser snow geese (Chen caerulescens caerulescens) in autumn for premigratory staging. To better understand the potential impacts of human disturbance on lesser snow geese, we investigated species composition of, and temporal and age-related variation in, their diet during staging. Depending on age and time of collection, between 35.2 and 94.1% of the diet (aggregate percent wet mass, n = 75) consisted of 2 species of plants; underground stems of tall cotton-grass (Eriophorum angustifolium), and aerial shoots of northern scouring-rush (Equisetum variegatum). The diet varied between August and September (P = 0.0089), morning and afternoon (P < 0.0001), but not between age classes (P = 0.066). Throughout staging, lesser snow geese consumed more tall cotton-grass during the afternoon than during the morning (P < 0.05). Tall cotton-grass was a larger component of the afternoon diet in September than in late August (P < 0.05). In September, lesser snow geese consumed more northern scouring-rush in the mornings than in the afternoon (P < 0.05). Nighttime freezing, interspecific differences in nutritional quality, and plant senescence likely constrained the diet of lesser snow geese to a small number of food items. Because alternative foods may not be available, human disturbance should be minimized in areas that provide these forage species.

Autumn Diet of Lesser Snow Geese Staging in Northeastern Alaska

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