Aspects of the ecology of feral cats on Dassen Island, South Africa.

Abstract

Numbers of Felis catus on Dassen Island increased from 20-25 in May 1979 to 37-50 in June 1980. Kittens were born in 8 months of the year with birth peaks in October-November and in January. Mean litter size was 2.7 and 80% of kittens born between August 1979 and January 1980 survived until June 1980. Kittens died from starvation and disease. In June 1980 51-56% of cats were <1 yr old. The number of cats is recovering rapidly from heavy culling. Depredation by cats is a potential threat to sea-bird colonies. An 'average' cat's annual diet included: 134 European rabbits Oryctolagus cuniculus, 37 jackass penguins Spheniscus demersus, 25 Cape cormorants Phalacrocorax capensis, 31 other birds and 24 house mice Mus musculus. Each cat killed 105 rabbits and 13 birds each year, the balance of its diet being made up by carrion.-from Author