Survival of 265 female and 224 male [Formula: see text]1-year-old white-tailed deer (Odocoileus virginianus) marked on 3 study areas in central and northern Illinois was examined. Females lived, on average, 5.5 years and males 2.5 years from birth. Twenty-four of the 265 females lived for at least 10 years from birth, but only 14 males for at least 5 years. The oldest female was 18 years of age and the oldest male 9 years old when killed. For both sexes, deaths were concentrated in the fall, with males more likely to die than females. Males were more likely to die from hunting and females from other causes. Known wounding deaths were 1 for every 3 retrieved deer for archers and 1 for every 8 for firearms hunters. Dispersing male and female yearlings and 2-year-olds suffered greater mortality than did sedentary deer. Annual survival rates of yearling and older females ranged from 0.56 (dispersing 2-year-olds) to 0.92 (8-year-olds). Survival was significantly reduced for 5-year-old females compared with those both older and younger. Annual survival of rates males ranged from 0.35 (dispersing 2-year-olds) to 0.76 (sedentary yearlings).
Survival of 265 female and 224 male ≥1-year-old white-tailed deer (Odocoileus virginianus) marked on 3 study areas in central and northern Illinois was examined. Females lived, on average, 5.5 years and males 2.5 years from birth. Twenty-four of the 265 females lived for at least 10 years from birth, but only 14 males for at least 5 years. The oldest female was 18 years of age and the oldest male 9 years old when killed. For both sexes, deaths were concentrated in the fall, with males more likely to die than females. Males were more likely to die from hunting and females from other causes. Known wounding deaths were 1 for every 3 retrieved deer for archers and 1 for every 8 for firearms hunters. Dispersing male and female yearlings and 2-year-olds suffered greater mortality than did sedentary deer. Annual survival rates of yearling and older females ranged from 0.56 (dispersing 2-year-olds) to 0.92 (8-year-olds). Survival was significantly reduced for 5-year-old females compared with those both older and younger. Annual survival of rates males ranged from 0.35 (dispersing 2-year-olds) to 0.76 (sedentary yearlings).
Range expansion and population increase by coyotes (Canis latrans), reduced hunting and trapping, and intensified agricultural practices in the Midwest have altered red fox (Vulpes vulpes) mortality, although relative impacts of these factors are unknown. We examined mortality causes and survival of red foxes in urban and rural agricultural areas of Illinois, using radio telemetry data from 335 foxes (Nov 1996 to May 2002). We used Akaike's Information Criterion to evaluate six survival models for foxes reflecting 1) environmental effects, 2) intrinsic effects, 3) temporal effects, 4) behavioral effects, 5) social effects, and 6) a global model. Environmental and intrinsic models of survival were optimal for adult foxes. Adult foxes with low (0‐20%) and high (80‐100%) percentages of row crops in their home ranges had higher survival than adults with moderate percentages (40‐70%). Heavier adults at capture also survived better. A global model (all covariates) was optimal for juvenile foxes. Higher juvenile survival associated with larger litters, lower body fat, and reduced dispersal time. Yearly survival ranged from 0.18 for rural male juveniles to 0.44 for rural female adults. Adult survival rates (0.35) were 11% higher than juvenile survival rates (0.24). Yearly survival varied for urban foxes due to cyclic outbreaks of sarcoptic mange (Sarcoptes scabei). Thus, summer survival (May‐Sep) of urban juveniles ranged from 0.10 (mange present) to 0.83 (no mange recorded). Mange was the most common (45% of all fatalities) source of mortality for urban foxes, followed by road kill (31%). We recorded only 4 mange fatalities (2%) for rural foxes. Rural foxes experienced low hunting mortality (7%) and equivalent road kill and coyote predation fatalities (40% each). Sources of mortality for midwestern foxes have dramatically changed since the 1970s when hunting was the major cause of mortality. Coyote predation has effectively replaced hunting mortality, and cyclic patterns of mange outbreaks in urban fox populations might indicate a dynamic source or sink relationship to surrounding rural fox populations. Absent mange, urban areas might provide refugia for red foxes where coyote populations persist at high densities in rural areas. Managers of sympatric urban and rural wildlife populations must understand survival dynamics influencing the population at the landscape level.
We document effects of West Nile virus (WNV) on American Crows. More than two thirds of our crows died of WNV infection, peaking when the proportion of infected mosquitoes at roosts was greatest. WNV antibody prevalence in crows was low. Local ecologic effects can be dramatic as WNV inhabits new areas.
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