Factors influencing the use of winter-burnt grassland by foraging bald ibises Geronticus calvus

Abstract

Use of winter-burnt grassland by foraging bald ibises, Geronticus calvus, and the abundance of invertebrates in winter-burnt grassland were investigated in relation to the time elapsed after burning In Natal high grassland. Bald ibises were recorded feeding In dormant, winter-burnt grassland from less than 4 h after burning up to 35 days after burning. Insects and other potential prey items were significantly more abundant 0-7 days than 14-37 days after burning: most specimens consisted of fire-killed arthropods. Live Insects increased in abundance soon after the appearance of new growth 46 - 82 days after burning. Possible factors Influencing the use of winter-burnt grassland by foraging bald ibises are discussed with emphasis on changes In the relative abundance of living and dead arthropods in relation to the time elapsed after burning.