Harmon P. Weeks

SPATIAL ECOLOGY OF COYOTES ALONG A SUBURBAN‐TO‐RURAL GRADIENT

Abstract Coyotes (Canis latrans) are now ubiquitous throughout most of the eastern United States; however, little information exists on how they are able to exploit and thrive in fragmented landscapes. We investigated home ranges, movements, and scale-dependent resource selection of coyotes along a gradient (suburban/exurban/rural) of anthropogenic disturbance. Home-range sizes varied along a suburban-to-rural gradient and were inversely correlated to urbanization (R2 = 0.79, P < 0.001). Habitat composition and coyote use of 95% (home range) and 50% (core area) contours were nonrandom. Coyotes used corridor habitat extensively and avoided urban and crop-field habitats. Forested habitat was used extensively for diurnal cover. Rural coyotes traveled greater distances at faster rates than did suburban/exurban coyotes. Diel activity patterns were similar along the gradient, suggesting that coyotes responded similarly to differing levels and types of human activity. Coyotes appeared to assess habitat quality at the landscape scale and exploited small, disjunct resource patches present in developed landscapes. We believe that the availability of foraging habitat and travel corridors is critical to movement of coyotes in areas of high human activity.

Salt Preferences and Sodium Drive Phenology in Fox Squirrels and Woodchucks

Salt preferences and sodium (Na) drive were examined in southern Indiana populations of fox squirrels ( Sciurus niger ) and woodchucks ( Marmota monax ). Animal use of salt-impregnated wooden pegs demonstrated that Na compounds were highly preferred. Both seasonal variation in peg use and the phenology of animals licking the road surface for residues of winter-applied sodium chloride demonstrated definite seasonal variation in Na drive. Spring peaks for both species and an additional autumn peak in squirrels were clearly associated with sudden increases in dietary intake of potassium (K) in spring and decreases in Na intake in squirrels in autumn. The high K intake is postulated to interfere with otherwise efficient Na-conserving mechanisms.

Movements and Use Patterns of White-Tailed Deer Visiting Natural Licks

Movements to natural mineral licks and frequency of visits were examined for white-tailed deer (Odocoileus virginianus) in southern Indiana from February 1979 to September 1980. Nearly all deer with known home ranges visited licks. Most deer frequented licks situated within or adjacent to their home ranges, but other nearby licks were also used. The longest known trip to a lick outside of home range boundaries was 3.2 km; most trips were

Ca, Mg, and P in the annual diet of deer in South-Central Indiana

The nutritional importance of the macroelements calcium, magnesium, and phosphorus for the plant and animal kingdoms is well documented. Although these elements are among the most commonly assayed in evaluating forages eaten by wild and domestic herbivores, only a few studies have sampled vegetation monthly through 1 or more years to assess changes that might occur in mineral contents. We have analyzed the important forage components in the annual diet of white-tailed deer (Odocoileus virginianus) in south-central Indiana for Ca, Mg, and P to determine if temporal changes occur in dietary levels of these nutrients.

Use of Total Body Electrical Conductivity to Predict Northern Bobwhite Lipid Mass

Several studies have developed models to predict lipid mass of live birds from a measure of total body electrical conductivity (TOBEC), yet few studies have assessed the validity of these models with independent data. We used independent datasets from Illinois (n = 38), Indiana (n = 94), and Missouri (n = 41) to develop and validate multivariable regression models (calibration equations) predicting lipid mass of live northern bobwhites (Colinus virginianus) from measurements of body mass and TOBEC. We assessed the validity of each model by determining the mean difference between predicted and observed lipid mass for bobwhites used in constructing the other 2 models (prediction error). First-order models (i.e., lacking interactions and quadratic terms) were selected as most useful for predicting lipid mass for all 3 datasets (R 2 = 0.71-0.92, Ps < 0.01). Mean predicted lipid mass was < 19.1% (2.32 g) of observed means. Large prediction errors associated with 1 dataset may have resulted from differences in methods. Models for the other 2 datasets (Indiana, Missouri) were relatively accurate: mean prediction errors were <3.4% of observed means. Removing TOBEC from Indiana and Missouri models changed their accuracy little; mean prediction errors for these cross-validated models were <2.3% of observed means. Consequently, the benefits of using models with TO-BEC cannot always be assured.

Sodium provision and wild cottontail rabbits : morphological change in adrenal glands

A direct relationship exists between sodium (Na) nutrition and morphology of the mammalian adrenal cortex, but little research on the relationship between soil Na levels and herbivore populations exists. Consequently, we assessed the effect of Na on wild cottontail rabbits (Sylvilagus floridanus) inhabiting Na poor soils in southcentral Indiana by characterizing their adrenal mass and histology prior to, and following, provision of supplemental Na. Data and tissues were collected at annual (1985-87) hunter check stations and during the 1987 breeding season at the Atterbury Fish and Wildlife Area

Calcium, magnesium, and potassium in hair of deer from areas of contrasting soil productivity

Differences in mineral nutrient composition of soils have been considered to affect health and population characteristics of free-ranging animals, particularly herbivores. Contents of Ca, Mg, and K in hair of female fawn white-tailed deer (Odocoileus virginianus) were measured for eight consecutive years to determine if soil and annual effects occurred in two areas of contrasting soil productivity in Illinois. Soil differences may account for some of the autumnal weight difference (7.2 kg for 4 yrs of observation) observed in fawn does from the areas. Ca, Mg, and K were assayed, because these macronutrients were known to differ in soils of the areas and were presumed to differ in forages. In 6 of the 8 yrs, at least one element was significantly different (P ≤ 0.05) between areas. Significant (P ≤ 0.05) differences for K occurred in 5 yr, for Ca in 4 yr, and for Mg in 2 yr. Ca and Mg were lower in hair in 7 yr from deer collected from the area in which extractable Ca and Mg were higher in soils; that is, hair Ca and Mg levels tended to be inversely related to levels of plant-available Ca and Mg in soil. For 7 of the 8 yr, K content was lower in hair from the area of lower soil K content. Within one area, between-year differences occurred for Ca and K and for Ca and Mg in the other area. Between-year differences in diet selection and annual climatic effects on mineral uptake of forages, among other factors, may account for some of the latter differences. Results for hair analyses suggest that macronutrient differences in Ca, Mg, and K occur in the diets of these populations and may account for some of the weight difference observed between the areas.

Growth of Cottontail Rabbits (Sylvilagus floridanus) in Response to Ancillary Sodium

A field investigation of sodium nutriture of cottontail rabbits was conducted at the Atterbury Fish and Wildlife Area, Edinburgh, Indiana, from 1985 to 1987. Eight 20-ha grids, comprising four replicates of two treatments, control and sodium-provisioned, were established in spring 1985. Provision of ancillary sodium was not initiated until spring 1986 to allow assessment of extant differential growth by treatment area prior to experimental manipulation. Cross-sectional data relating to growth was obtained from specimens collected at an annual-hunt check station. An integrated-sigmoidal Richards function was used to model growth of rabbits. The effect of years was tested among controls; growth did not differ for either males or females between sampling years. Prior to the initiation of sodium provision neither sex of rabbit displayed any differential pattern of growth based upon harvest location. Following provision of ancillary sodium there was no discernible alteration of growth pattern within males. However, among females asymptotic weight and growth period increased, while the shape parameter of the growth function decreased. Sodium deprivation, exacerbated by maternal reproductive investment, may require increased energetic expenditure to maintain sodium-related homeostasis, which is expressed in less than optimal growth.