The association of the roof rat (Rattus rattus) with the Himalayan blackberry (Rubus discolor) and Algerian ivy (Hedera canariensis) in California

The roof rat (Rattus rattus) utilizes Algerian ivy and the Himalayan blackberry for food and cover, often living Independent of man. Algerian ivy is the most popular ornamental and ground cover plant in California and is used extensively for landscaping, particularly in southern California. The Himalayan blackberry, inhabited by feral roof rats, grows abundantly in northern California along inland creeks and in pastureland of the Sacramento Valley and in the foothills of the Sierra Nevada. Rats construct platform nests on or within the dense layer of canes that accumulate within the thickets. Information on distribution and recommendations for the control of the roof rat within the blackberry habitat are presented. A potential human plague threat exists where rodent cohabitants of the berry thickets may become involved in epizootics.