Determination of the environmental fate of ground squirrel carcasses /

Abstract

A field study was conducted in Lewis and Clark County, Montana, during the summer of 1986 to determine the fate of Columbian ground squirrel (Spermophilus columbianus) carcasses in the environment. Ground squirrel carcasses were marked with radio transmitters and placed in situations and locations similar to those found in actual rodent control operations. Carcasses were monitored until their fate was determined or until they were no longer considered attractive to scavengers. Red fox (Vulpes fulva) was the primary scavenger in this study. Striped skunk (Mephitis mephitis) and birds (corvids and/or raptors) were the other mammalian and avian scavengers identified. Carrion-eating insects quickly attacked the carcasses and were important in determining the maximum exposure time of the carcasses to scavengers. Factors determining the risks to scavengers from rodent control operations and management techniques to reduce nontarget hazards are discussed.

Scavenging of rodent carcasses following simulated mortality due to field applications of anticoagulant rodenticide

“…These values are lower than those measured for the corpses of other rodents (Spermophilus Sullivan 1988;Tobin and Dolbeer 1990). We cannot exclude that our daily presence on a single plot and/or the handling of vole carcasses have influenced the behavior of the scavengers as shown previously (Kostecke et al 2001;Wobeser and Wobeser 1992).…”

“…More generally, several studies assessing the transfer of pesticides or pathogens to scavengers have shown that scavenging rates were the highest during the first days (Balcomb 1986;Tobin and Dolbeer 1990;Ward et al 2006;Wobeser and Wobeser 1992). Tobin and Dolbeer (1990) have notably shown that average percentages of songbird carcasses remaining in cherry and apple orchards, were, respectively, 60 and 95 % after 24 h and 31 and 62 % after 96 h. It was also evidenced that scavenging rates depend on several factors such as habitat (vegetation, localization…) but also weather conditions, seasons, density and visibility of carcasses and scavengers present on the site (Kostecke et al 2001;Linz et al 1997;Sullivan 1988;Ward et al 2006).…”

“…Latin names are: black kite (Milvus migrans), carrion crow (Corvus corone), common buzzard (Buteo buteo), dog (Canis familiaris), red fox (Vulpes vulpes), and red kite (Milvus milvus) were higher than those of plot 1 (autumn: 52 %; spring: 82 %). According to Sullivan (1988) or Tobin and Dolbeer (1990), the rates are mainly influenced by the scavengers present around the treated plots. In our study, if they were not related to the number of potential scavengers observed, the composition of the diurnal community contributed to determine the persistence of vole corpses as shown by the higher rates measured when carrion crow was the dominant species.…”

“…Based on a feeding experiment, Ntampakis and Carter (2005) have observed that brown rat Rattus norvegicus carcasses placed in grasslands or close to farm buildings were picked up by red kites Milvus milvus and red foxes Vulpes vulpes often within a few hours of being left out and almost always within 2 days. It was also assessed that three-quarters of squirrel carcasses were scavenged in 6 days or less (Phillipson and Wood 1976;Sullivan 1988). More generally, several studies assessing the transfer of pesticides or pathogens to scavengers have shown that scavenging rates were the highest during the first days (Balcomb 1986;Tobin and Dolbeer 1990;Ward et al 2006;Wobeser and Wobeser 1992).…”

Rodent tissue residue and secondary hazard studies with bromadiolone1

“…Fate of Spermophilus columbianus carcasses. The purpose of this study was to determine the date of killed S. columbianus carcasses in the environment (Sullivan & Pond, 1986). Twenty carcasses were fitted with radio transmitters.…”