Lonnie P. Hansen

Factors affecting capture myopathy in white-tailed deer

Capture myopathy can be a significant cause of mortality for white-tailed deer (Odocoileus virginianus) and other ungulates. Capture and handling may affect rates of myopathy. During 1988-92 we captured 415 white-tailed deer with rocket-nets and Clover traps as part of a deer mortality study in northcentral Missouri. We placed radiotransmitters on 250 of these deer and assumed capture myopathy was the cause of death for 23 deer that died within 26 days of capture. All myopathy suspects were captured with rocket-nets. We examined differences in 6 handling variables for rocket-net-captured deer that died within 26 days of capture and those that lived more than 26 days. We fit a Cox proportional hazard model to these data to determine the capture variables most affecting myopathy for deer captured with rocket-nets. Survival of captured deer was most influenced by the number of deer captured together. Process times should be minimized to reduce stress to captured deer.

White-tailed Deer Dispersal Behavior in an Agricultural Environment

ABSTRACT Dispersal behavior was examined for 119 male and 102 female white-tailed deer (Odocoileus virginianus) fawns marked in central and northern Illinois. Fawn movement behavior was recorded for 35 single, 78 pair and 10 triplet litters that survived intact beyond family breakup in late spring. Males (65%) dispersed at a higher rate than females (39%). Females dispersed Apr.–Jul., while males dispersed Apr.–Jul. and Sep.–Nov. The dams and siblings movements most affected fawn movement behavior with most fawns of dispersing/migrating females and siblings leaving their natal range. As yearling-adult densities and forest cover increased on our study areas, female fawn dispersals decreased. Habitat scarcity in spring coupled with high fawn survival into the spring months promoted higher than expected female dispersal behavior. Distance traveled to a new range did not differ among study areas, years or month of dispersal for either sex. Single fawns were as likely to disperse as fawns from pairs or triplets. Control of high density deer populations will be more difficult where female dispersal is prevalent, as in the agriculturally dominated Midwest landscape.

An Evaluation of Sex-Age-Kill (SAK) Model Performance

Abstract The sex-age-kill (SAK) model is widely used to estimate abundance of harvested large mammals, including white-tailed deer (Odocoileus virginianus). Despite a long history of use, few formal evaluations of SAK performance exist. We investigated how violations of the stable age distribution and stationary population assumption, changes to male or female harvest, stochastic effects (i.e., random fluctuations in recruitment and survival), and sampling efforts influenced SAK estimation. When the simulated population had a stable age distribution and λ > 1, the SAK model underestimated abundance. Conversely, when λ < 1, the SAK overestimated abundance. When changes to male harvest were introduced, SAK estimates were opposite the true population trend. In contrast, SAK estimates were robust to changes in female harvest rates. Stochastic effects caused SAK estimates to fluctuate about their equilibrium abundance, but the effect dampened as the size of the surveyed population increased. When we considered both stochastic effects and sampling error at a deer management unit scale the resultant abundance estimates were within ±121.9% of the true population level 95% of the time. These combined results demonstrate extreme sensitivity to model violations and scale of analysis. Without changes to model formulation, the SAK model will be biased when λ ≠ 1. Furthermore, any factor that alters the male harvest rate, such as changes to regulations or changes in hunter attitudes, will bias population estimates. Sex-age-kill estimates may be precise at large spatial scales, such as the state level, but less so at the individual management unit level. Alternative models, such as statistical age-at-harvest models, which require similar data types, might allow for more robust, broad-scale demographic assessments.

An epizootic of hemorrhagic disease in white-tailed deer in Missouri.

As part of a white-tailed deer (Odocoileus virginianus) survival study in Missouri (USA) we were actively monitoring 97 radio-collared deer when 8 (8%) died. This mortality, which occurred from 20 August to 23 September 1996, consisted of five adult females, two yearling females and one yearling male. Based on the seasonality of this mortality and the isolation of epizootic hemorrhagic disease virus (EHDV) serotype 2 from one of these animals, we believe that these losses resulted from an epizootic of hemorrhagic disease. The remains of five unmarked deer that may have died from HD also were found on the study area during this same period. During the fall following this mortality, we tested serum from 96 deer taken by hunters in the immediate area. Fifteen (16%) were positive for EHDV or bluetongue virus (BTV) antibodies as determined by agar gel immunodiffusion tests. Serum neutralization test results indicated that previous infections were caused by EHDV virus serotype 2. Based on these data, and assuming that there was no prior exposure to EHDV serotype 2 in this population, the exposure rate for this epizootic was 24% of which 8% died. We noted hoof interruptions in only two of the 96 deer sampled. During this mortality event, the Missouri Department of Conservation received no reports of dead deer, and without the radio-monitored animals the event would have been undetected.

Factors affecting space use overlap by white-tailed deer in an urban landscape

Variation in the size and overlap of space use by white-tailed deer (Odocoileus virginianus) has broad implications for managing deer–human conflicts and disease spread and transmission in urban landscapes. Understanding which factors affect overlap of home range by various segments (i.e., age, sex) of an urban deer population has implications to direct contact between deer on disease epidemiology. We assessed size of home range and overlap of space use using the volume of intersection index (VI) for deer in an urban landscape by sex, age, season, and time of day. We found mean space use was larger for males than for females, for males <3 years old than for males ≥3 years old, and during nocturnal hours compared with diurnal hours. We also identified larger space use by both sexes during the nongrowing than the growing season. Overlap of space use for female and male deer in our urban landscape differed considerably depending on demographic (i.e., age) and environmental variables (i.e., time, season). For example, highest mean VIs occurred between 6-year-old females (mean = 0.51 ± 0.10) and 5- and 6-year-old males (mean = 0.49 ± 0.14); no mean VI was greater than 0.31 between females and males for any age combination. Variation in overlap of space use for urban deer provides new information for managing deer–human conflicts and direct transmission of disease between various segments of a deer population in an urban landscape.

Effects of Nest Boxes on Fox Squirrel' Demography, Condition and Shelter Use

A 7-year study of the effects of nest boxes on an unexploited population of fox squirrels (Sciurus niger) was conducted on two adjacent upland forests. Boxes were placed at three densities on Area A for 2.5 years, then were moved to Area B for 3.5 years. Subadults of both sexes and adult (15 + months) males made extensive use of nest boxes in winter, but only adult males showed any significant (P< 0.05) increases in density and survival in the presence of nest boxes. The use of nest boxes by breeding. age females was sporadic in winter and boxes appeared to be avoided by pregnant females. The use of boxes was negatively affected by the presence of a cavity in the same tree, but positively affected by nest box height. Boxes placed on slopes in sup- pressed trees with entrances facing southwesterly were preferred (P< 0.05). Adult males preferred boxes placed in mature, mixed species forests, whereas adult females were attracted to boxes placed close to an edge in successional forests of low stem densi- ty. Both sexes avoided boxes placed in ravine forests frequented by gray squirrels (S. carolinensis). Nest boxes placed well below the tree canopy were avoided by breeding females. It is postulated that fox squirrel adaptations to resource limited environments, primarily fire-adapted savanna forests, include an asocial, dispersed social system and the use of leaf nests for shelter. It is also postulated that these adaptations precluded a sustained positive response to nest boxes.

Characteristics of Winter Habitats Used by Deer in Illinois

We examined characteristics of winter habitat used by white-tailed deer (Odocoileus virginianus) on intensively farmed land in central and northern Illinois. Forty-three variables were measured to describe land use and human presence within 10.36-km2 blocks centered within 32 wintering sites of deer and 31 sites avoided by deer in winter. The percent of forest in refuge, total forest available, unpastured upland forest >50 years old, shrub-old field, and total upland forest available were significantly correlated (P < 0.05) with deer presence in winter; only percent of forest in refuge and total forest available had a significant influence on deer presence in winter when all 5 variables were used together in discriminant analysis. Use of the 2-variable model to classify sites where deer were located or where they were absent in winter averaged 83% correct for the 63 sites examined. Refugia and/or large blocks of forest are necessary for successive generations of deer to live long enough to develop traditions of use for specific sites in the intensively farmed, dispersed woodland ranges in the midwestern United States. J. WILDL. MANAGE. 52(3):552-555 The retreat of white-tailed deer into localized habitats in winter appears to be a stereotyped and evolutionary adaptive behavioral response to harsh weather and predation in northern latitudes (Mattfeld 1974, Mech 1984). South of the deep snow belt in the midwestern United States where land use has reduced forest cover to scattered wood lots or to linear strands of forest along waterways, deer congregate in winter to reduce the effects of harsh weather and to escape harassment and predation by humans. Deer come together on winter sites in late fall and remain until spring when many disperse or migrate to widely scattered summer ranges (Zwank 1974, Gladfelter 1978, Masek 1979). In northern Illinois, deer movements between widely separated summer and winter ranges have been recognized since the 1940s, prior to the beginning of modern-day deer hunting with shotguns (Pietsch 1954); however, the extent of this dispersal and migratory behavior in Illinois has only recently been documented (Nixon and Hansen 1986) and appears confined to the central and northern counties (Fig. 1). Our objectives were to determine landscape characteristics where deer are found in winter and to determine if these characteristics differ in eastcentral, westcentral, and northern Illinois. We thank D. L. Swofford, Illinois Natural History Survey, for statistical assistance and F. D. Loomis, Illinois Department of Conservation, for financial support. J. E. Chelsvig helped conduct aerial surveys. R. J. Stoll, Jr., Ohio Division of Wildlife; H. L. Gladfelter, Iowa Department of Natural Resources; and W. R. Edwards, G. C. Sanderson, and the editorial staff of the Illinois Natural History Survey reviewed the manuscript. This report is a contribution (in part) of Federal Aid in Wildlife Restoration Project W-87-R, the Illinois Department of Conservation, the U.S. Fish and Wildlife Service, and the Illinois Natural History Survey cooperating.

Migration Behavior among Female White-Tailed Deer in Central and Northern Illinois

ABSTRACT Thirty-nine female white-tailed deer (Odocoileus virginianus) were migrators from three study areas in central and northern Illinois, 1980–1993. Migrants averaged 21.5%, 9.4% and 14.6% of marked females known alive each year on the east-central, west-central and northern study areas, respectively. Females migrated to a summer range between late Feb. and early Jul. and to the winter range between late Sep. and early Jan. Spring migration distances averaged between 7.3 and 15.9 km from the winter range. Female fawns of migrating mothers were more likely to disperse or migrate than were fawns of sedentary mothers. Migrating females survived as long as sedentary females and significantly better than females that dispersed, but fawn recruitment was lower for migrating females compared with sedentary females. Winter severity did not affect return behavior from a summer range. Hunter harassment on the summer range initiated migration back to the winter range in 59% of 22 monitored migrations for 14 radio marked females. Prevailing winds from the winter or summer range appeared to help locate these ranges for 10 of 19 spring migrations for 16 females and three of seven fall migrations for four females. Migration behavior allows females to more fully utilize the fragmented landscapes of the agricultural Midwest. Migration behavior among females appears to result from resource competition among females including parturition sites where female densities are high and available habitats are scarce.

A Comparison of Deer and Turkey Harvest Data Collection Methods in Missouri

Abstract Harvest information often forms the basis for deer and turkey management decisions. Thus, for many state agencies, collection of representative harvest data is an essential part of the management program. We compared reporting rates and biological information obtained from mandatory in-person and telephone checking (telecheck) for white-tailed deer (Odocoileus virginianus) and eastern wild turkey (Meleagris gallopavo) in Missouri, USA. We subsequently compared this information to that obtained from commercial meat processors to determine if these data could substitute for in-person check stations for collecting age of harvested deer. To conduct our study we randomly selected a telecheck group and a control group from firearms deer and spring turkey hunters in 2003 and 2004, respectively. The telecheck group called a toll-free number to report deer or turkey harvests; the control group reported at established check stations. We compared the sex, age, and number of reported animals harvested by each group. We also compared the reported harvest for the control groups and statewide permittees. For deer, we found no difference in the total harvest reported by telecheck and control group participants. However, the control group reported harvesting more deer than those in the statewide group (0.78 and 0.59 deer per person, respectively). Concomitantly, we found that a lower proportion of commercially processed deer were 0.5 years of age (0.16 and 0.22 for males and females, respectively) than for those self-processed (0.22 and 0.32 for males and females, respectively). There was no difference between self- and commercially processed male or female deer in the distribution of 1.5- and ≥2.5-year-olds. The reported turkey harvest was higher for telecheck and statewide groups than for the control (0 turkeys, 0.64, 0.63, and 0.67; 1 turkey, 0.28, 0.26, and 0.27; 2 turkeys, 0.08, 0.11, and 0.06 for the telecheck, statewide, and control groups, respectively). Recorded spur length did not differ for telecheck and control groups but was longer for the statewide than for the control group (<2.5 cm: 0.54 and 0.51; 2.5–3.8 cm: 0.44 and 0.44; >3.8 cm: 0.01 and 0.03 for control and statewide groups, respectively). Although harvest reporting between telecheck and control groups differed, the differences were small and the significance may have been an effect of large sample sizes. We suggest that telecheck may serve as a suitable replacement for in-person checking of deer and turkey in Missouri. Lastly, age data from deer 1.5 years of age and older collected at meat processors represented distribution data obtained from in-person check stations.

Habitat Relationships and Population Dynamics of Deer in the Intensively Farmed Midwestern United States

In the mid western farm belt, where forest cover often totals 70%) for fawns and females and moderate (> 60%) for males; (2) large forests that are hunted each fall where survival of fawns and females is moderately high (> 50%) and that of antlered males is low (< 26%); and (3) small woodlots and strands of bottomland forest along rivers and streams where both sexes are frequently hunted to extinction. Seasonal movements of deer among these habitats are extensive and contribute to a wide dispersion of deer in summer and fall.