We identified seven Leptospira serovars in wildlife and the presence of leptospiral DNA in water sources at a natural area within a fragmented habitat in Illinois, US. These serovars have been implicated in domestic animal and human leptospirosis, a reemerging zoonotic disease, whose reservoirs include wildlife and domestic animals. We live trapped medium-sized mammals (n=351) near building (H-sites) or forest sites (F-sites). Using serology, we evaluated exposure to Leptospira (L. interrogans serovars Autumnalis, Bratislava, Canicola, Icterohaemorrhagiae, Pomona; L. kirschneri serovar Grippotyphosa; L. borgpetersenii serovar Hardjo). Using PCR, we tested for the presence of leptospires in eight water samples (ponds, creeks, and rainwater runoff) collected near trapping sites. We identified antibody titers in raccoons (Procyon lotor; 121/221) and Virginia opossums (Didelphis virginiana; 60/112), but not in feral cats (Felis catus; 0/18). We found significant differences in overall Leptospira seroprevalence between years (P=0.043) and animal's age in 2008 (P=0.005) and 2009 (P=0.003). Serovars Autumnalis, Bratislava, and Grippotyphosa showed significant differences among age groups with the highest seroprevalence in adults. Females had a higher seroprevalence for Icterohaemorragiae in 2008 (P=0.003) and Hardjo in 2009 (P=0.041). Risk of exposure to Leptospira was higher at F-sites compared to H-sites (odds ratio 2.3, 95% confidence interval 1.3-3.9, P=0.002). We captured more animals with titers >1:800 at H-sites, but there was no association between titer levels and capture site. Six of eight water sources were Leptospira-positive; however, there was no correlation between trapping locations of seropositive animals and positive water sources. Natural areas create opportunities for interspecies interactions, favoring leptospires transmission across species. Understanding that Leptospira serovars are present in natural areas is an integral part of the safe human and pet recreational use of these areas. Our study should raise awareness and build on public education designed to prevent disease transmission between species.

There is growing evidence that maternal experience influences offspring via non-genetic mechanisms. When female three-spined sticklebacks ( Gasterosteus aculeatus ) were exposed to the threat of predation, they produced larger eggs with higher cortisol content, which consumed more oxygen shortly after fertilization compared with a control group. As juveniles, the offspring of predator-exposed mothers exhibited tighter shoaling behaviour, an antipredator defence. We did not detect an effect of maternal exposure to predation risk on the somatic growth of fry. Altogether, we found that exposure to an ecologically relevant stressor during egg formation had several long-lasting consequences for offspring, some of which might be mediated by exposure to maternally derived cortisol. These results support the hypothesis that female sticklebacks might influence the development, growth and behaviour of their offspring via eggs to match their future environment.

We conducted a cross-sectional study from 2008 to 2009 to evaluate the occurrence of feral and wild cats and the risk of Toxoplasma gondii infection in terrestrial wildlife in a natural area in Illinois, USA. Felids are definitive hosts for T. gondii and cats are a key component of rural and urban transmission of T. gondii. We selected four forest sites within the interior of the park and four edge sites within 300 m of human buildings. Feline and wildlife occurrence in the natural area was determined with the use of scent stations, motion-detection cameras, and overnight live trapping. Based on scent stations and trapping, feral cats used building sites more than forest sites (scent stations: P=0.010; trapping: P=0.083). Prevalence of T. gondii antibodies was determined with the use of the indirect immunofluorescent antibody test (IFAT) with a titer of 1:25 considered positive; T. gondii antibodies were detected in wildlife at all sites. Wildlife species were classified as having a large home range (LHR) or a small home range (SHR), based on published estimates and using a cutoff of 100 ha. Small–home-range mammals had a higher prevalence of antibody to T. gondii (odds ratio [OR] =4.2; P=0.018) at sites with a high frequency of cat occurrence (defined as ≥9 cat occurrences across three detection methods); this finding indicates that feral cats are the most likely source of environmental contamination. Overall, the prevalence of antibody to T. gondii among LHR mammals was significantly higher than the prevalence among SHR mammals (OR=7.1; P<0.001). Small–home-range mammals are an essential part of T. gondii–antibody prevalence studies and can be used as sentinels for risk of disease exposure to humans and wildlife in natural areas. This study improves our understanding of ecologic drivers behind the occurrence of spatial variation of T. gondii within a natural area.

The management of wildlife populations for sustainability has evolved as a main theme in natural science over the years and sophisticated statistical models have been developed for use in the prediction and characterization of population dynamics. Though game species serve as the common focus for many studies, the evaluation of populations involving threatened and endangered animals warrants signifi cant attention as well. Due to reduced population densities and habitat fragmentation, the formal statistical modeling of endangered species populations presents signifi cant challenges. In many cases, much scientifi c expertise exists with regards to a particular endangered species but data are scarce. Herein we adopt a hierarchical statistical model that formally accounts for expert knowledge while utilizing limited data to learn about the population dynamics of the Red-Cockaded Woodpecker, an explicitly managed and endangered species in the United States. The models we present are also used to make statistical population projections while rigorously accounting for uncertainty.

Southeastern Illinois is dominated by cropland, and the remaining pastures or grasslands are marginally suitable for breeding Loggerhead Shrikes (Lanius ludovicianus), owing, in part, to limited nest sites. From 1998 through 2000, we recorded poor nest success (26%) among shrikes, although results of earlier studies (1967-1972) in this region indicated that nest success was 72 to 80%. Clutch size (5.7 eggs) and fledglings/ successful nest (4.4 young/successful nest) were similar to those reported in previous studies. During our study, generalist mammalian predators were abundant, and most nest failures (88%) were caused by predation. We suggest that the loss of grassland habitat and agricultural intensification has resulted in reduced nest success, and this may be true in other areas of the species' range as well.

With a set of external measurements from a sample of known-sex American crows (Corvus brachyrhynchos) in central Illinois, we determined whether a published discriminant function for sex determination was applicable to crows in a different geographic location than the reference sample. Low classification success with this equation, likely due to geographic size differences in crows between regions, led to the creation of new age-specific discriminant functions, which correctly classified the sex of 100%, 100%, and 89% of hatch-year, subadult, and adult crows, respectively. This technique for gender determination is of timely importance as the American crow is a sentinel for West Nile virus transmission, and ecological studies of this species are important in understanding transmission dynamics. Gender determination by discriminant function of these Midwestern crows indicated that the 2002 West Nile virus epizootic did not cause sex-biased mortality.

Abstract Renesting decisions and annual fecundity are crucial for interpreting other demographic information, yet are infrequently reported. We used radiotelemetry to monitor female Dickcissels (Spiza americana) throughout the 1999 and 2000 breeding seasons in southeastern Illinois. Overall fecundity (regardless of whether females remained in the study area throughout the breeding season) was 0.61 ± 0.13 female fledglings per year. Of females that remained within the study area, 94% fledged young (1.25 ± 0.15 female fledglings per year). Most females (62%) that experienced nest failure emigrated from the study area (moved >10 km) in 2.8 ± 0.6 days; others (36%) initiated subsequent nests in 8.5 ± 0.8 days. After fledging ≥1 young, 95% of females ceased breeding for the season. Successful and failed nest sites were indistinguishable on the basis of vegetative characteristics. Moreover, replacement nests had similar vegetative characteristics and were similar distances from habitat edges, compared with initial nests, which suggests that female Dickcissels do not or cannot “improve” nest-site characteristics in response to nest failure. We observed two behaviors unusual in female Dickcissels: one bird that fledged two broods in one season, and the return of five females banded in 1999 to the study site in 2000.

Abstract The postfledging period is the least-studied stage of avian life cycles. Survival during this period has crucial effects on population dynamics. Survival of fledged young may be influenced by dispersal from their nest sites, because juveniles must cope with the hazards of novel environments. To better understand this important life stage, we used radiotelemetry techniques to study postfledging movements and survival of 50 juvenile Eastern Meadowlarks (Sturnella magna) at Prairie Ridge State Natural Area in Jasper County, Illinois, in 1999 and 2000. Juveniles began to move away from the nesting area in the third week after fledging. Most juveniles moved only 1–5 km from their birth site by the end of the study (90 days). Juvenile survival for the first 90 days after fledging was estimated as 56–69%. Mortality was greatest during the first week of the postfledging period, likely because of high rates of predation. Juvenile meadowlarks are flightless at fledging and thus are vulnerable to predators. We did not observe a second peak of mortality, as other studies have shown, at independence or when juveniles began to move away from their nest areas. The present study suggests that immediate postfledging movements may not be related to dispersal to future breeding sites, but rather occur in response to immediate needs for food resources and security from predators. Furthermore, the data suggest that presumed mortality patterns and estimated levels of juvenile survival are suspect; that interspecific variability of juvenile survival and postfledging movements may be considerable; and that detailed, longer-duration field studies are necessary to elucidate this important demographic period.

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.

Determining the sizes and characteristics of home ranges among American Crows (Corvus brachyrhynchos) in spring/summer is essential for understanding the importance of this species in the transmission of West Nile virus. In late spring, summer, and early fall of 2002, we radio-tracked 45 American Crows to estimate their movements and habitat preferences in urban and adjacent agricultural habitats in east-central Illinois. The 95% minimum convex polygon home ranges averaged 9.6, 6.7, and 6.4 km(2) for hatch-year, sub-adult, and adult crows, respectively. Proportional habitat use was investigated at two scales: (a) at the study site scale, there was a preference for low- to medium-density urban habitat and avoidance of forested habitat; and (b) at the home range scale, there was a preference for agricultural cover and avoidance of high-density urban habitat.

Exposure to anthropogenic endocrine disruptors has been listed as one of several potential causes of amphibian declines in recent years. We examined gonads of 814 cricket frogs (Acris crepitans) collected in Illinois and deposited in museum collections to elucidate relationships between the decline of this species in Illinois and the spatial and temporal distribution of individuals with intersex gonads. Compared with the preorganochlorine era studied (1852–1929), the percentage of intersex cricket frogs increased during the period of industrial growth and initial uses of polychlorinated biphenyls (PCBs) (1930–1945), was highest during the greatest manufacture and use of p,p-dichlorodiphenyltrichloroethane (DDT) and PCBs (1946–1959), began declining with the increase in public concern and environmental regulations that reduced and then prevented sales of DDT in the United States (1960–1979), and continued to decline through the period of gradual reductions in environmental residues of organochlorine pesticides and PCBs in the midwestern United States (1980–2001). The proportion of intersex individuals among those frogs was highest in the heavily industrialized and urbanized northeastern portion of Illinois, intermediate in the intensively farmed central and northwestern areas, and lowest in the less intensively managed and ecologically more diverse southern part of the state. Records of deposits of cricket frog specimens into museum collections indicate a marked reduction in numbers from northeastern Illinois in recent decades. These findings are consistent with the hypothesis that endocrine disruption contributed to the decline of cricket frogs in Illinois.

We investigated the survival and population structure of Blanding's turtles (Emydoidea blandingii Holbrook) in two local forest preserves in suburban Chicago using radio telemetry and mark-recapture from 1994-1998. Our objective was to assess the status of this state threatened species through direct comparisons of a population in rural central Wisconsin and by making comparisons of these populations to others using relevant literature. Five years of mark-recapture data revealed that the suburban Chicago populations were small, estimated at 36 and 25 turtles. Furthermore, population structures based on carapace lengths were significantly skewed toward adults in suburban Chicago, with only two hatchlings found. It was evident that juvenile turtles were lacking in suburban Chicago, implying low juvenile recruitment when compared to the central Wisconsin population and to relevant literature. Although annual survival of adults was high (range 0.933-1.00), population size estimates were so small that Blanding's turtles in suburban Chicago are at risk of extinction in the coming decades. Results suggest that management interventions that focus on maintaining high adult survival and increasing juvenile recruitment will likely be the most beneficial to the persistence of Blanding's turtles in suburban Chicago. Future studies are needed to assess what factors limit juvenile recruitment in suburban Chicago.

Abstract Annual fecundity is a demographic parameter that is elemental to population biology, but accurate measures of fecundity are rarely obtained. We used radiotelemetry to follow female Eastern Meadowlarks (Sturnella magna) throughout the 1999-2000 breeding seasons in southeastern Illinois to estimate their annual fecundity and assess if the outcome of initial nesting attempts affected site selection for subsequent nests. Thirty-four females built 52 nests (1.53 ± 0.12 nests female−1), but only 21 females (62%) fledged young. Only 44% of females renested at the study site, and more females (53%) emigrated after successfully fledging young from an initial nest than after failing in their first attempt (21%). Nest-site characteristics were similar between successful and failed nests for both initial and subsequent attempts. Females that failed during first attempts did not change nest characteristics for renests. Given that few females were double-brooded and that unsuccessful females did not persistently renest, annual fecundity for females nesting at the study site was between 1.27 ± 0.38 and 1.36 ± 0.37 female young year−1. On the basis of our fecundity measure, we estimated that annual adult survival of 59–61% was necessary for maintenance of a stable population (λ = 1.0). Failure of most females to attempt to raise two broods suggests that double brooding carries substantial costs for meadowlarks.

Decline of red fox (Vulpes vulpes) populations in Illinois has been attributed to altered geographic landscapes and the eastward expansion of the coyote. To investigate effects of habitat use and competition with coyotes on diets of foxes in intensively farmed landscapes of Illinois, we analyzed carbon and nitrogen isotope ratios (δ13C and δ15N) of foxes, coyotes (Canis latrans), and other local species. Foxes were categorized as rural (agricultural habitat, coyotes present), urban (urban habitat, coyotes absent), or from an agricultural research facility at the University of Illinois (South Farms, agricultural habitat, coyotes absent). Rural foxes had higher fur isotopic values (δ13C and δ15N) than rural coyotes, indicating that coyotes caused foxes to consume prey items from higher trophic levels and eat more C4 plants. Urban foxes had lower isotopic values (δ13C and δ15N) than South Farms foxes, suggesting that habitat use partly determined fox diets; foxes in urbanized habitats consumed prey at lower trophic levels within a largely C3 plant based food web. Models of competitive exclusion by coyotes were better predictors of fox long-term diets, including pup rearing, while habitat use models predicted fox diets on a narrower timescale. Competitive exclusion by coyotes might be an important factor explaining the decline of foxes in the intense farming areas of Illinois.

A dipstick immunochromatographic assay used for West Nile virus (WNV) detection in mosquitoes was investigated for application to testing of fecal, saliva, and tissue samples from dead American Crows (Corvus brachyrhynchos). Results suggest that VecTest may be an efficient method for WNV detection in field-collected, dead American Crows, although confirmation of results and further investigation are warranted.

Management of high-density suburban deer populations requires knowledge of survival and movement to predict population trends. However, natural and human-induced influences on survival and movement of suburban deer are poorly understood. Therefore, we marked 208 (60 bucks,, 148 does) white-tailed deer (Odocoileus virginianus) from forest preserves in Chicago, Illinois, USA (1994-1998). Seasonal and annual survivorship was >0.80 for 114 does and 13 bucks. Deer-auto collisions produced the highest mortality rates, 0.10 (95% CI 0.06 to 0.14) and 0.17 (95% CI 0.0 to 0.37). Spring dispersal for does was 7% (3 of 41) for fawns and 6% (5 of 83) for yearlings and adults; and for bucks it was 50% (8 of 16) for fawns and 7% (2 of 30) for yearlings and adults. All dispersals were <9 km, except for I parous doe that moved 33.9 kin. Doe home ranges aver-aged 51 (95% CI 40.5 to 61.5), 26 (95% Cl 22.0 to 30.0), and 32 (95% Cl 19.6 to 44.4) ha for winter-spring, summer, and fall, respectively. A priori, we developed a set of 10 logistic regression models for suburban doe survival relative to home. range size and traffic exposure indices. Using Akaike's Information Criterion (AIC), the best models included covariates reflecting home range size and traffic exposure. Inference across a greater than or equal to90% confidence set of survival models indicated substantial spatial heterogeneity in mortality risk for suburban does. High Survival and philopatry by suburban deer apparently contribute to their overabundance in metropolitan areas.