Wildlife Research Area Research Articles

Eastern Tent Caterpillar Control on Choke Cherry, 1981

Abstract A field of choke cherry in the Rose Lake Wildlife Research Area, Clinton Co., Ml was selected for evaluation of insecticides. Five materials were tested. Egg masses and small tents from neighboring areas were transferred to selected trees (1.5 to 4.5 m high) in the study area. Larvae were allowed to develop for approximately 3 weeks after transfer. The trees were treated on May 19 when the tents had enlarged to approximately 20 to 40 cm in diameter and the maj’ority of larvae were 3rd and 4th instars. The number of larvae per tent were counted prior to treatment. Insecticides were applied with a trombone sprayer and trees were sprayed to the run off point. The number of tents sprayed varied from 5 to 8 depending on the treatment. Skies were sunny at treatment time with an air temperature of 18°C and a light breeze of 5-10 mph. Mortality evaluations were made 7, 10 and 13 days after treatment by counting the number of dead larvae in each tent. Data were analyzed using AN0VA techniques. An arcsine percent transformation was performed on the percentage data.

Changes in the herb layer of the riverine woodland in the Sengwa Wildlife Research Area, Zimbabwe

The changes in the dominant species of the herb layer, in particular Blumea gariepina DC., of riverine woodlandin the Sengwa Wildlife Research Area in Zimbabwe, were monitored over a period o f five years. Factors contributing to these changes appear to have been rainfall, utilization and interspecific competition.

Structure of association in impala, Aepyceros melampus

1. The associatons and movements of 400 marked impala of known age were studied in the Sengwa Wildlife Research Area, Zimbabwe, from May 1975 to May 1978. 2. Female and juvenile impala were dispersed in a clan system. The average level of association (measured by Sorensen's index) between members of the same clan was 0.27 and between members of neighbouring clans 0.02. There was no significant correlation between separation of individuals' centres of home range and association within clans. 3. The associations of impala were summarised in a maximum spanning tree. Females emerged as a uniform and discrete group without sub-groups or families, but young adult females of the same clan associated preferentially with their peers of equal age. No dominance hierarchy or consistent leader was detected among females, although animals 5 years and older were more likely to move independently. 4. A numerical method for calculating coefficients of relatedness in a clan, or large social group, is described (Appendix). The average level of relatedness between impala peers is estimated to be higher than between individuals one or more years apart in age. It is suggested that this may influence the association pattern. 5. Non-juvenile males did not have a stable social structure, and their associations were more open than those between females, from whom they were frequently segregated. Young and old males associated preferentially by age, but middle-aged males avoided each other. This variation is related to different developmental requirements, particularly learning about male-male interactions by young animals and expression of dominance by middle-aged animals.

Changes in the Biomass and Productivity of Woodlands in the Sengwa Wildlife Research Area, Zimbabwe

(1) Changes in biomass and annual production measured over the period 1972 to 1976 in four woodlands, the miombo, the Sengwa/Lutope riverine, the Manyoni riverine and the mopane woodland, are described. (2) The greatest changes in biomass were recorded in the miombo woodland where it is estimated that the biomass decreased by 45%. The biomass of the Sengwa/Lutope riverine, a woodland with three strata, increased by 14%, whilst that of the Manyoni riverine changed little. The biomass of the mopane woodland decreased by over 6%. (3) The annual production of the miombo, the Manyoni riverine and the mopane woodlands decreased between 1972 and 1976, whereas that of the Sengwa/Lutope riverine woodland increased. (4) The change in the biomass of the miombo woodland was primarily a result of the removal by elephant of large trees which were not replaced due to the effects of elephant and fire. (5) The increase in biomass of the Sengwa/Lutope riverine woodland was a result of recruitment to both the tree and shrub layers. The tree biomass increased by 394%, and the shrub biomass by 207% but the biomass of the upper canopy trees decreased by 10%. (6) The decrease in biomass of the mopane woodland which is seldom affected by fierce fires, was almost certainly due to the effects of elephant. (7) Due to the opening up of the canopy and the coppicing of damaged trees, more browse is now in reach of the smaller browsing animals in all woodlands except the Manyoni riverine. (8) Elephant appear to have been responsible for the decreases in biomass but fire has also contributed.

The diet of Impala (Aepyceros melampus) in the Sengwa Wildlife Research Area, Rhodesia

The seasonal variation in the plant morphological part composition of the dict of Impala in the Sengwa Wildlife Research Area, Rhodesia, was determined by the analysis of rumen content samples from shot animals. The grass species composition of the diet was examined by microscopic identification of grass fragments found in the rumens. The seasonal variation in the dicotyledonous species composition of the diet was studied by direct observation of feeding animals. The protein contents of the rumen contents and faeces were used as measures of diet quality. In the wet season, grass was selected in preference to dicotyledonous plants, and grass leaf was the preferred plant part. In the late wet and early dry seasons, forbs were the principal food. The proportion of woody dicotyledons in the diet was at a maximum in the mid‐dry season, when diet quality was at a minimum. Diet quality was directly related to the proportion of grass in the diet. Female Impala had a significantly higher quality diet than males, probably as a result of differential habitat selection.

Dry-Season Overlap in Activity Patterns, Habitat Use, and Prey Selection by Sympatric African Insectivorous Bats

We used mist nets, ultrasonic sensors, light tags, and analysis of feces to examine habitat use, activity patterns, and prey selection of some insectivorous bats during the dry season at the Sengwa Wild Life Research Area (18?10'S; 28013'E) between 7 and 28 June 1977. The results show broad overlap in all parameters investigated for the 13 species present in the area during the dry season. During the wet season, some species of insectivorous bats relied more on beetles than on moths as food, or vice versa. The lack of food partitioning, particularly in the dry season, appears to conflict with theories of niches and competitive exclusion, but it is in accord with predictions based on optimum foraging strategy. We conclude that most insectivorous bats are opportunistic feeders, a strategy which results in a mosaic of specialized and generalized diets and which is compatible with their energetic demands. We report the first record of Tadarida chapini from Zimbabwe (Rhodesia). FOOD AND ROOSTS are two potentially limiting resources which may be partitioned by sympatric species of bats (Tamsitt 1967, Fenton 1970, McNab 1971, Humphrey 1975). Partitioning of food resources can involve habitat (Handley 1967) and/or time (Kunz 1973) and/or types of food (Black 1972, 1974). A variety of studies has shown that bats can be either very selective in their feeding (Buchler 1976a), or generalized in their diets reflecting local abundances of insects (Belwood and Fenton 1976, Anthony and Kunz 1977). Bradbury and Vehrencamp (1976) found broad overlap in prey size between five species of Neotropical emballonurids which showed flexible feeding behavior, and Kunz (1974) reported that Myotis velifer adjusted its foraging patterns to meet local conditions. A reflection of the flexibility in foraging behavior is provided by Fenton and Morris' (1976) experiments which demonstrated that some insectivorous bats were opportunistic, rapidly responding to concentrations of insects. Similar responses to concentrations of food occur for other bats as well (Fleming et al. 1977, Gould 1978). Our purpose here is to report some observations we made of activity patterns, habitat use, and prey selection by some sympatric African insectivorous bats, and to interpret these results in the context of resource partitioning (e.g., Schoener 1974) and optimal foraging strategy (e.g., Pyke et al. 1977). The field data for this study were gathered during the dry season in an African deciduous forest; they are compared to previously published wet-season data from the same locality (Fenton 1975, Fenton et al. 1977). We made our observations in the vicinity of the Hostes Nicolle Institute of Wild Life Research (18?10'S; 28013'E, ca. 820 m above sea level) in the Sengwa Wild Life Research Area, ca. 110 km west of Gokwe, Zimbabwe. Most of our work was done at the same sites used by Fenton (1975) and Fenton et al. (1977), and included miombo and mopane woodland, riparian forest, pans with and without water, and some locations along the Sengwa and Lutope Rivers (for details of vegetation and physiography see Cumming 1975). Several different types of habitats can be identified in the study area based on the composition of plant communities, but most of the area is open woodland, whether miombo or mopane (fig. 1). However, woodlands along the rivers may have higher densities of trees than woodlands away from the rivers, and the Sengwa River is bordered by open, grassy floodplain (fig. 1). While during the wet season some bats were more commonly captured in a specific habitat (Fenton 1975), during the dry season this distinction was much less clear. Furthermore, captures in one habitat or another do not necessarily reflect the use of these habitats by insectivorous bats (see below). MATERIALS AND METHODS We captured bats in 9 or 12 m, 351 mm mesh mist nets or in a Tuttle trap (Tuttle 1974) set at various locations near the Institute. Bats were removed from the nets or trap, sorted by sex and species, and then either released (sometimes after tagging) or held overnight in cloth bags to permit collection of feces. Bats held for collection of feces were those which had fed prior to capture (determined by palpation of the BIOTROPICA 12(2): 81-9

Avian Nest Dispersion and Fledging Success in Field‐Forest Ecotones

Observations of 21 species of open—nesting passerines breeding in contiguous field and forest habitats at Rose Lake Wildlife Research Area, Michigan, were made during 1974 and 1975. Data were collected on nest dispersion, clutch—size, and fledging success in relation to the field—forest edge. Losses of eggs or nestlings were attributed to predation, inclement weather, Brown—headed Cowbird (Molothrus ater) parasitism, nest desertion, hatching failure, and adult death. Each bird species seemed to have a preferred distance from the habitat discontinuity that was used as a nest site. Furthermore, nests were not uniformly distributed on the area. Over one—half of the nests were found within ±15 m of the habitat discontinuity. Seventy—five percent of the nests belonged to birds characteristic of mixed breeding habitats, i.e., birds requiring an open overstory canopy with elevated singing and observation perches and dense cover near the ground for nesting and feeding. These mixed—habitat species also accounted for the increase in avian species nesting near edges. Based on Kendall rank and partial rank correlation tests, increasing numbers of nests and the percentage of total clutches, <3 eggs were found to be negatively correlated with increasing distance from the habitat discontinuity. Correlation between fledging success and increasing distance from the edge was positive and highly significant. Of the several mortality factors investigated, predation and cowbird parasitism were found to be the most important. The increased predation rate with decreased distance from the edge was attributed primarily to a functional response to higher numbers of nests and a greater activity of potential nest predators in the vicinity of the habitat discontinuities. Our results indicate that habitat suitability decreases with increasing numbers of nests toward the narrow field—forest edges. Although such abrupt habitat discontinuities did attract a variety and abundance of birds characteristic of habitats with mixed life—form, these discontinuities seemed to function as "ecological traps" by concentration nests and thereby increasing density—dependent mortality. Ironically, the cowbird was also a victim of the increased predation rate. As these man—made forest edges are of recent origin, they are perhaps unrepresentative of the ecological niche in which these species evolved, and thus they may be poorly adapted to cope with the increased nest predation.

Evaluation of a Korean Pheasant Introduction in Missouri

We evaluated the success of releases of 4,172 South Korean pheasants (Phasianus colchicus karpowi) in the Missouri River bottom in west-central Missouri by measuring dispersal, breeding effort, brood production, and survival during and after the 5 release years, 1967-71. Dispersal of tagged pheasants released at 2 sites in 1970 averaged 2.9 km; the farthest movement was 24 km. A winter survey in 1972 indicated that distribution of pheasants in the area approximated the annual dispersal limits. High initial mortality of released birds was suggested by recoveries of tagged birds released in 1970. Substantial numbers of broods reported by landowners in annual surveys, and moderate crowing cock indices for 6 years following the last release indicate a reproducing population that is stabilizing at a low density. Lack of suitable nesting cover may be a factor limiting further growth of this population. J. WILDL. MANAGE. 41(4):616-623 In recent years land-use changes have altered the environment in a large part of Missouri, rendering it less suitable for native upland game populations. Despite these alterations much of the area appears to be potential pheasant range. Ring-necked pheasants (Phasianus colchicus torquatus) were first introduced into Missouri in the early 1900's. From 1904 to 1933 an estimated 40,000 ringnecks were distributed by the Game and Fish Department (Bennitt and Nagel 1937:53). The disappearance of the bird convinced game biologists that with existing land-use trends and climatic conditions in Missouri the ring-necked pheasant could not reproduce and survive in sufficient numbers to sustain hunting except in the northwest counties (Fig. 1). In 1958 the Department of Conservation began a program of experimentally releasing the progeny of several pure strains and hybrids of wild-trapped Asian pheasants. Initia breeding stock was secured through a cooperative agreement with the Bureau of Sport Fisheries and Wildlife in conjunction with its Foreign Game Introduction Program (Bump 1963). One of the subspecies selected for release in Missouri was the South Korean ring-necked pheasant (P. c. k rpowi). South Korean ringnecks were selected because they were known to breed in captivity, their behavioral attributes were similar to the other successfully introduced ringnecks, and their native habitats were similar in many respects to those in Missouri, the upper Midwest, and parts of the eastern United States. The South Korean climate (Bohl 1970) with hot, humid summers characterized by frequent heavy rainfall, and average winter temperatures below freezing with snow falling no more than 30 days annually, is similar to the Missouri climate. 1 Contribution from the Missouri Cooperative Wildlife Research Unit (U.S. Fish and Wildlife Service, Missouri Department of Conservation, Wildlife Management Institute, and University of Missouri-Columbia, cooperating), from Federal Aid Project 13-R-23, Missouri Department of Conservation, and from the Missouri Agricultural Experiment Station Journal Series Number 7616. The senior author was supported by a Paul K. Wehmiller Fellowship. 2 Present address: Ashland Wildlife Research Area, School of Forestry, Fisheries and Wildlife, University of Missouri-Columbia, Ashland 65010. 3 Present address: Division of Habitat Preservation Research, U.S. Fish and Wildlife Service, Washington, D.C. 20240. 616 J. Wildl. Manage. 41(4):1977 This content downloaded from 157.55.39.102 on Mon, 03 Oct 2016 04:08:36 UTC All use subject to http://about.jstor.org/terms KOREAN PHEASANTS IN MISSOURI -Wollard et al. 617

Deer Foods during Years of Oak Mast Abundance and Scarcity

Rumen contents of white-tailed deer (Odocoileus virginianus) during November and early December of 1966 through 1973 in a mountainous area of southwestern Virginia revealed that acorns made up an average of 76 percent by volume of the deer's diet when acorns were abundant. When a mast failure occurred, deer replaced acorns with large amounts of the leaves of prostrate evergreen plants and shrubs and mushrooms. Proximate analysis of rumen contents revealed that diets containing acorns were higher in nitrogen-free extract and crude fat and lower in mineral content. In mast-free diets both mineral matter and protein increased. Proximate analysis and in vitro tests of composite diets indicated that when mast was present the diets were more digestible and were higher in fat and soluble carbohydrates. A relatively low value of 1.5 kcal/g for estimated digestible energy in mast-free diets suggests that when deer must rely on this type of diet during the winter season, their energy requirement for maintenance may not be met. The addition of oak mast to winter diets increased estimated digestible energy to 3.1 kcal/g, or a level adequate to meet the maintenance energy requirement. A forage inventory in the major forest types indicated that mature stands of pitch pine-bear oak (Pinus rigida-Quercus ilicifolia) produced the greatest quantity of important staple foods for deer during late fall and early winter. J. WILDL. MANAGE. 39(2):330-336 Oak mast predominates in the fall and winter diets of white-tailed deer wherever and whenever it is abundant in the Southeast (Ruff 1938, Pearson 1943, Pearson and Burnett 1940, Harlow 1961, Harlow and Hooper 1971). Acorns are often available to deer for eight months or more (Goodrum 1959). They are high in carbohydrates (King and McClure 1944, Morrison 1957) and provide energy and nutrients during the winter. During years of oak mast scarcity deer must turn to other forages. In this study, data from 1966 through 1973 are used to compare the effects of oak mast abundance and scarcity in late November on food selectivity patterns of deer. Nutritional values of rumen samples and of composite diets reconstructed from rumen analysis were estimated. Important forages available to deer were inventoried in the major forest types of the study area. DESCRIPTION OF THE STUDY AREA The Broad Run Wildlife Research Area in Craig County, Virginia, is within the Ridge and Valley Province. The soils are derived from shale, sandstone, and conglomerate bedrock. Thirty-five percent of the approximately 3,035-ha area is composed of the pitch pine-bear oak forest cover type; 33 percent, oak-hickory-yellowpoplar-white pine (Quercus spp.-Carya spp.-Liriodendron tulipifera-P. strobus) type; and 19 percent, mixed oak-pine type (Whelan 1962). Site indexes (the height which upland oaks attain in 50 years [Olson 1959]) range from 35 to 60 with pitch pine-bear oak containing the lowest index. Elevations range from 469 to 689 m above sea level. Slopes range from 0 to 58 percent and face primarily northwest. From 1959 to 1964, approximately 389 ha (12 percent of the study area) were dis330 J. Wildl. Manage. 39(2):1975 This content downloaded from 207.46.13.149 on Mon, 03 Oct 2016 04:08:45 UTC All use subject to http://about.jstor.org/terms DEER FOODS AND OAK MAST AVAILABILITY * Harlow et al. 331 turbed by clearcutting and heavy selection cutting. In 1957, 23 wildlife clearings were established which ranged in size from 0.30 to 1.33 ha. Seneca (1961) estimated 120 deer on the study area, or 1 per 27 ha. Hunter observation and annual kill statistics indicate little change in deer numbers since 1961 (Weekes 1974).

Evaluating Ruffed Grouse Reintroduction in Missouri

The ruffed grouse (Bonasa umbellus) was almost extirpated in Missouri in the early 1900's, probably because of habitat destruction through repeated burning and overgrazing. An attempt to reintroduce grouse during the 1940's failed. Since then, improved habitat conditions for forest game warranted other attempts. Wild-trapped birds from Ohio and Indiana were released in Missouri on the Ashland Wildlife Research Area, Boone County; and Daniel Boone Memorial Forest, Warren County. Thirty-nine grouse were released in 1959 at Ashland and 18 on the Boone Forest. Subsequent releases brought the Ashland Area total to 119 birds and the Boone Forest total to 143. For evaluating results of reintroduction, data were obtained during eight breeding seasons, 1960-67. Thirty-six drumming activity centers were found at Ashland, 1962-67, and 26 on the Daniel Boone Forest, 1961-67. Reproduction at Ashland was confirmed in 1963, 1964, 1965, and 1966 by catches of young grouse; and four unbanded drumming males, evidently progeny of the released birds, were trapped. Ruffed grouse appear to be established on both areas, but densities are low and occupancy of range beyond the release areas has been limited. Missouri is on the southwestern edge of the known ruffed grouse range. Early reports cited by McKinley (1960) are contradictory, but Missouri grouse populations were perhaps never as high nor as uniformly distributed as in states to the north and east. Nevertheless, ruffed grouse were once present throughout most of the state and were common in some localities until 1900. By the early 1930's grouse were reported from only 19 counties and probably totaled fewer than 100 birds (Bennitt and Nagel 1937:41). They continued to decline, and the last authenticated observation was made in Warren County in 1956, by J. B. Lewis. Although native ruffed grouse reached very low levels, it is doubtful that they were extirpated. Efforts to reestablish grouse in Missouri were made in 1940-43. Birds obtained from the Sandhill Game Farm, Inc., Babcock, Wisconsin, were released on three refuges in the southern Ozark region of the state. These birds persisted for some time, but finally disappeared. An evaluation of these early releases was not made, and nothing is known about the reason for their failure. Missouri's forest game habitat has improved in the last 20 years. As a result, it has been possible to restore white-tailed deer (Odocoileus virginianus) and eastern wild turkeys (Meleagris gallopavo silvestris) to much of the original range (Murphy 1965:142, Lewis 1961:507, 509). Encouraged by the improved prospects for forest game, the Missouri Department of Conservation initiated an experimental ruffed grouse reintroduction program on two central Missouri areas in 1959. Wild grouse trapped in southern Indiana and Ohio (at the latitude of central Missouri) were used as stock in the new program. These regions appeared to be the best potential source of grouse, considering habitat and climate. The purpose of this paper is to report 8 years' data on survival, dispersal, and reproduction of these released birds, and to 'A contribution from Federal Aid to Wildlife Restoration Project 13-R-19, Missouri Department of Conservation, and from the Missouri Cooperative Wildlife Research Unit: U. S. Bureau of Sport Fisheries and Wildlife, Wildlife Management Institute, Missouri Department of Conservation, and University of Missouri cooperating. 2 Present address: Alaska Department of Fish and Game, Fairbanks.

Foods and Nutrition of Ruffed Grouse in Missouri

In efforts to reestablish the ruffed grouse (Bonasa umbellus) in Missouri, three experimental areas were recently stocked with wild birds trapped in Ohio and Indiana: Ashland Wildlife Research Area, Boone County; Daniel Boone State Forest, Warren County; and Carman Spring Refuge, Howell County. Seven thousand samples of droppings collected in all months, February, 1961-September, 1964, were analyzed to learn principal foods and native plants that might be managed to benefit grouse under Missouri conditions. Plant foods of 111 kinds, or groups, and 33 animal foods were identified. Diet and degree of utilization of foods varied greatly by season and year. Principal foods in decreasing order of volume were: unidentified green leaf materials, hop hornbeam, acorns, wild grapes, tick trefoils, Japanese (multiflora) rose, ladies' tobacco, fragrant sumac, bittersweet, bush clovers, Korean lespedeza, hazelnut, Christmas fern, and sedges. No animal food was important in the year-round diet. Nutritional analyses based upon food composition and volume percentages in the diet showed that body building protein (15.5 percent) was taken in greatest amount during summer, fat (6.4 percent) and carbohydrates (71.5 percent) as fat and energy producing compounds were taken most in winter, and the largest mineral amounts (6.6 percent) were taken during the summer period of production, growth, and development. Selection of quality foods to meet bodily needs was indicated. Approximately 15 percent, by volume, of all foods was furnished by high canopy trees, 45 percent by understory trees, shrubs, vines, and brambles, and 40 percent by herbaceous forbs and grasses. The data emphasize the need for mixed vegetative types in productive grouse habitat. The purpose of this paper is to report on the principal foods of ruffed grouse on release areas where attempts were made to reestablish this species in Missouri. Nutritional values and management possibilities for some of the more important food species also are considered. Data were derived from 7,000 grouse droppings collected during all months, February, 1961 to September, 1964. The ruffed grouse originally inhabited most of the forested area of Missouri. Populations in early settlement days are unknown, but have been estimated in the hundreds of thousands. Numbers declined rapidly following settlement; birds were limited to a few Ozark and northeastern counties by 1900. Hunting was made illegal in 1905, and ruffed grouse have never since been legally hunted in Missouri (Bennitt and Nagel 1937:41). The recent history of Missouri grouse is uncertain; gradual decline in population has continued, but it is doubted that the species was exterminated. Reports persisted that a few birds remained in isolated locations. Experimental stocking with Ohio and Indiana wild-trapped ruffed grouse was begun in 1959. Thanks are due Biologist John B. Lewis for assistance on most field trips in search for grouse and study materials. STUDY AREAS AND RESTOCKING

Further Studies of Bob-White Mobility in Central Missouri

Because of differing results of mobility studies conducted at widely separated points in the bob-white's (Colinus virginianus) range, and because of lack of specific information on this subject under Missouri conditions, a series of investigations on mobility of wild bobwhites was initiated by the Missouri Cooperative Wildlife Research Unit. First results of this study were reported by Murphy and Baskett (1952). (Bobwhite mobility in central Missouri, Jour. Wildl. Mgt. 16: 498-510, 1952). The investigation reported here, the second of the series, was designed to supplement the first. The studies were made on and in the vicinity of the Ashland Wildlife Research Area in Boone County, central Missouri. This area comprises 2,240 acres of abandoned farm land and second growth oak-hickory woodland; approximately one-third of the acreage consists of abandoned fields along ridges, and other openings which are frequented by quail and are widely distributed through the area. Quail densities on the entire Ashland Area averaged about one bird per nine acres in late winter. The open north-central portion carried somewhat higher densities, as did neighboring farmland to the north and west, where most off-area trapping was conducted. The land south and east of the Ashland Area is mostly wooded, and supported fewer quail. Data were secured by trapping and banding wild bob-whites. Materials used in the two studies were similar: cock-and-hen traps baited with grain in fall and winter, and furnished with decoy females in spring and summer. Quail were banded with numbered aluminum bands, but colored plastic leg bands and neck markers were used as supplementary marking systems. Procedures were also similar, but in the present study, the Ashland Area was trapped somewhat less intensively, and the surroundings more intensively, than in the previous investigation. The studies had in common an inadequate measure of egress. For detailed description of the area, of materials and procedures, and for a review of pertinent literature, the reader is referred to the paper by Murphy and Baskett (op. cit.). 'Contribution from the Missouri Cooperative Wildlife Research Unit: U. S. Fish and Wildlife Service, Wildlife Management Institute, Missouri Conservation Commission, Edward K. Love Foundation, and University of Missouri cooperating. The writer is indebted to T. S. Baskett who directed the research, and to D. A. Murphy, W. H. Elder, T. G. Scott, and P. C. Smith for advice and assistance.