Wildlife Damage Management, Internet Center for


Date of this Version

November 1979


DRC-1339 (3-chloro-4-methylbenzenamine HCI) is the active ingredient in Starlicide Complete, a commercial bait used to control starlings (Sturnus vulgaris) at animal feedlots throughout the U.S. Because of the recent widespread use of this product, par- ticularly within the wintering range of many raptors, they and other avian or mammalian scavenger or predator species may be exposed to large numbers of dead or dying star- lings and blackbirds (Icteridae) throughout the winter roosting season (November-March). Acute toxicity data are available for five species of raptors and a number of mammals indicating that DRC-1339 or its primary toxic metabolite DRC-2698 (N-(3-chloro-4-methylphenyl) acetamide, CAT), a potential roost toxicant, are only moderately toxic (100-300 mg/kg) to these animals. However, there are some avian and mammalian scavengers or predators to which these compounds are considerably more toxic (i.e., cats, owls, magpies). Secondary hazards have not been observed when DRC-1339 killed starlings were fed to three raptor species for as long as 141 days and to domestic cats for seven days (DeCino, Cunningham and Schafer 1966; Holler et al. 1979, unpubl, manuscript); however, the direct long-term effects of both chemicals have not been determined on raptors or other predatory or scavenger species. In order to decide if long-term studies are needed on predator or scavenger species, it is necessary to estimate accurately the degree of expected exposure to DRC-1339 and DRC-2698under actual use conditions. Since exposure will depend primarily upon the amount of these chemicals that remains in bird carcasses from bait ingestion until death, the metabolic or excretion rate of DRC-1339 and DRC-2698 must be known in target and at-risk, nontarget bird species. Although considerable data are available to determine the metabolic or excretion rate of DRC-1339 in target birds, some of these data are conflicting. We are therefore presenting the preliminary results of some of our current research with DRC-1339 and DRC-2698.