AGE, HABITAT AND TIDE EFFECTS ON FEEDING-ACTIVITY OF EMPEROR GEESE DURING AUTUMN MIGRATION

I studied feeding activity of Emperor Geese (Chen canagica) on the Ala ska Peninsula during autumn migration, 1991. Scan samples were used to estimate the proportion of birds feeding in flocks as a measure of fe eding intensity. Most geese fed during low tides and roosted during hi gh tides. However, flocks with disproportionately more juveniles conti nued to feed during high tides in either blue mussel (Mytilus edulis) beds (during relatively low high tides) or in vegetated habitats. Feed ing intensity was higher in mussel habitats than in mud/sand or vegeta ted habitats, and juveniles fed more than adults. Juvenile geese proba bly have greater nutritional needs than adults, and feeding during hig h tide may represent their attempt to satisfy these disproportionate d emands. Vegetated habitats may be used when high value bivalve prey ar e unavailable due to tidal inundation.