USDA National Wildlife Research Center Symposia


Date of this Version

August 2007


Published in: Witmer, G. W., W. C. Pitt, and K. A. Fagerstone, editors. 2007. Managing vertebrate invasive species: proceedings of an international symposium. USDA/APHIS Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA. Also available online at


The more than 50,000 species of plants, animals, and microbes introduced into the United States (US) cause more extinction of native species than most any other threat and cause more than $120 billion in damages and control costs each year. In particular, invasive mammals and birds cause major environmental and economic losses totaling about $46 billion per year in damage and control costs per year. Feral cats, rats, and hogs are especially serious pests. Pigeons and starlings are a major concern in cities and US agriculture. Prevention and management strategies will be discussed.