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 Alaska Peninsula during autumn migration, 1991. Scan samples were used to estimate the proportion of birds feeding in flocks as a measure of feeding intensity. Most geese fed during low tides and roosted during high tides. However, flocks with disproportionately more juveniles continued to feed during high tides in either blue mussel (Mytilus edulis) beds (during relatively low high tides) or in vegetated habitats. Feeding intensity was higher in mussel habitats than in mud/sand or vegetated habitats, and juveniles fed more than adults. Juvenile geese probably have greater nutritional needs than adults, and feeding during high tide may represent their attempt to satisfy these disproportionate demands. Vegetated habitats may be used when high value bivalve prey are unavailable due to tidal inundation.