Effects of the seasonal availability of short-tailed shearwaters (Puffinus tenuirostris) on the diet of red foxes (Vulpes vulpes) on Phillip Island, Victoria

Abstract

The diet of red foxes (Vulpes vulpes) on Phillip Island, Victoria, was assessed from the frequency of occurrence and volume of food items in stomachs of foxes killed during a 16-year control program (1983 to 1998). Of the 289 stomachs examined, 244 (85%) contained recognisable food items. Based on frequency of occurrence, the most common prey were short-tailed shearwaters (Puffinus tenuirostris, 47%), European rabbits (Oryctolagus cuniculus, 30%), house mice (Mus musculus, 15%), insects (15%), little penguins (Eudyptula minor, 12%), other birds (12%), sheep (Ovis aries 8%) and black rats (Rattus rattus 5%). The seasonal attendance patterns of P. tenuirostris caused substantial variations in the fox diet. When P. tenuirostris were present, between September and April each year, they were the most common food item, and when absent, they were replaced by rabbits. The sex of foxes did not appear to influence diet, but age did. Juvenile (<1 year old) foxes tended to eat fewer birds and sheep, and more insects, crabs, mice and blackberries (Rubus fructicosus), than did adult foxes.