Kerr County Research Articles

Dynamics of Pocket Gopher Distribution on the Edwards Plateau of Texas

Two species of pocket gophers are allopatric on the Edwards Plateau of central Texas but remains of both species have been found together in late Pleisto- cene and early Recent cave faunas. Geomys bursarius texensis occupies a small range in Mason and McCulloch, and perhaps Gillespie, Counties. Thomomys bottae confinalis is found in a small area in Kimble County and a broader, separated area in Edwards and Sutton counties. Thomomys b. confinalis no longer occurs at the type locality in Kerr County. No geographic variation was found in Thomomys popula- tions from the eastern Edwards Plateau, and isolation of the populations may have been relatively recent. Populations of Thomomys seem to be expanding at this time. The present small range of Geomys b. texensis may be only a remnant of its late Pleistocene range. Study of late Pleistocene small mammal assemblages from the southern Great Plains has disclosed many instances of species that lived sympatrically then but today are allopatric (Hibbard, 1970). Over most of North America, the present geographic ranges of the smooth-toothed pocket gophers (Thomomys) and the plains pocket gopher (Geomys bursarius) are separated (Hall and Kelson, 1959). The two species have been found together in late Pleistocene fossil deposits in Kansas (Schultz, 1969), Oklahoma (Stephens, 1960) and northern Texas (Dalquest, 1965). In Texas the present geographic ranges of Thomomys bottae and Geomys bursarius are separate but approach each other closely (Fig. 1) in the central part of the state. Remains from cave deposits in this same region show that the two species were sympatric from over 10,000 years ago to some 4,000 years ago, and probably later. The present allopatry is apparently a rela- tively recent development. We have attempted to cast light on the changes in distribution of these two species by mapping the distri- bution of pocket gophers of the eastern part of the Edwards Plateau, studying geographic variation in the populations involved, and attempting to find evidence of their past distribution. PRESENT DISTRIBUTION. Vernon Bailey collected a single speci- men of smooth-toothed pocket gopher 35 mi. E of Rock Springs,

Suitability of Grazing Enclosures for Deer and Livestock Research on the Kerr Wildlife Management Area, Texas

Suitability of Grazing Enclosures for Deer and Livestock Research on the Kerr Wildlife Management Area, Texas

Comparative Food Habits of Deer and Three Classes of Livestock

To observe forage competition between deer and livestock, the forage selections of a tame deer (Odocoileus virginianus), a goat, a sheep, and a cow were observed under four range conditions, using both stocked and unstocked experimental pastures, on the Kerr Wildlife Management Area in the Edwards Plateau region of Texas in 1959. The animals were trained in 2 months of preliminary testing. The technique employed consisted of recording the number of bites taken of each plant species by each animal during a 45-minute grazing period in each pasture each week for 1 year. Results indicated moderate to heavy competition for browse and mast between the deer and goat in all pastures during all seasons, and between the deer and all three classes of livestock in the winter. Browse and mast comprised over 50 percent of the deer's diet, except in the spring and summer, and over 50 percent of the goat's diet in all seasons. Following a decrease in available browse, sheep become competitive with deer for forbs. Forbs formed an average of 68 percent of the deer's diet and 65 percent of the sheep's diet in the ungrazed control pasture in the summer; the animals generally were grazing the same species. The added factors of bearing and nursing fawns, and growing antlers, contribute to the nutritional stresses on deer in the summer, the period when extensive die-offs of deer most frequently occur in the Edwards Plateau region. Competition for grass between deer and livestock probably is important only when grass is in a succulent stage in the spring and no other forage is available in quantity. Continuous grazing by animals tends to remove the most palatable species and concentrates competition on fewer, less palatable ones. Observations from the numerous replications of feeding times and places allow the conclusion that this technique provides a reliable index to preferred foods and staple foods. In the Edwards Plateau region of Texas, most of the rangelands are grazed by two or more classes of livestock along with deer. Research on the Kerr Wildlife Management Area, near Hunt, Texas, indicates that deer when managed and harvested properly can provide economic returns comparable to those from domestic livestock. But a study of the economic feasibility of management for livestock and deer in combination revealed the need for more exact knowledge of their competition for forage. To provide such information, a study of the food habits of cattle, sheep, goats, and deer was initiated in May, 1959, and concluded in May, 1960. The Kerr Wildlife Management Area is a research facility of the Texas Parks and Wildlife Department located in Kerr County in the eastern portion of the Edwards Plateau. This region, encompassing some 26,000 square miles of central Texas, probably is unique in its combined productivity of deer and livestock in high densities (Hahn 1945, Taylor and Hahn 1947). Previous studies of its vegetation in relation to deer and livestock were reported by Buechner (1944), Taylor and Beuchner (1943), and Whisenhunt (1949). On the Kerr Area, particularly the pastures involved in this study, the prominent vegetal expression is a savannah of live oak, in which Ashe juniper (Juniperus ashei) and shin oak are conspicuous. Part of the Kerr Wildlife Management Area contains 10, 96-acre deer-proof pastures which are used for a long-term study of the influence of combined sheep, goat, and cattle grazing rates on deer production. Each species of animal obviously has a different influence on the welfare of the others and on the forage resource in general, but the experimental design had revealed only the gross influence of combinations of animals. Performances of deer in experimental pas-

Livestock and Deer Activities on the Edwards Plateau of Texas

During the summer of 1955 observations and records were made of the grazing habits and daily activities of cattle, sheep, goats and white-tailed deer (Odoco&us virginiawus temnus) on experimental pastures of the Kerr Wildlife Management, Area in west-central Kerr County, Texas. This study was a part of a long-time project dealing with livestock-deer interactions initiated by the Texas Game and Fish Commission in cooperation with the Texas Agricultural Experiment Station. Previous studies on livestock or deer activities in Texas were made by Cory (1927), Buechner (1944) and Davis (1952). Bange cattle activities have been studied in Arizona by Culley (1938)) in Kansas by Moorfleld and Hopkins (1951)) in New Mexico by Kilpatrick (1955) and in Montana by Peterson and Woolfolk (1955). The latter study included a review of the literature dealing with the activities of range animals.

Ectoparasites from Swallow Nests, with the Description of a New Ceratophyllid Flea

The numerous limestone caves of Central Texas provide retreats for millions of Mexican free-tailed bats, Tadarida mexicana, and lesser numbers of several other species. These caves have been rather extensively investigated by personnel of this Department during studies designed to evaluate the importance of these insectivorous mammals as reservoirs and transmitting agents of rabies virus. One of the largest and most interesting Texas bat harborage is Frio Cave located in Uvalde County. The first chamber, a room of considerable size, has several entrances including two openings in the roof which admit sufficient daylight to create an environment suitable for swallow nesting. The bats hang farther back in the darkened areas of the cave. On March 30, 1955, several of the old swallow nests located in recesses along the walls and ceilings were examined for ectoparasites in association with my colleagues George C. Menzies and John S. Wiseman. The nests were composed of mud and lined with such materials as grass, wool and feathers. A good series of Ceratophyllus fleas (50), numerous Haenolaelaps mites and several Ornithodoros ticks were taken. Specimens of the birds were netted and the species involved was determined to be Petrochelidon fulva pallida, or Coahuila cliff swallow. The ticks were indentified by Glen M. Kohls, Rocky Mountain Laboratory, Hamilton, Montana, as 0. concanensis and R. W. Strandtmann, Texas Technological College, Lubbock, Texas, gave us the opinion that the mites are H. megaventralis. Additional nests were examined in May, 1955 at which time the eggs had been laid and a few young birds were hatched. A good series of the Ceratophyllus flea was again taken. H. me#gaventralis mites were swarming all over the nests and 0. concanensis ticks were common. The same Ceratophyllus flea was also found in abundance in nests of the Coahuila cliff swallow in caves in Kerr County during June, 1955. A large number was taken from caves on the Wison and Johnson Ranches in this County. This represents the second species of Ceratophyllus to be taken in Texas. J. S. Wiseman collected a good series of C. celsus from Petrochelidon albifrons nests at Camp Bullis, Bexar County, Texas, June 14, 1955. The discovery of these two bird fleas raises the total number of known species of these ectoparasites in Texas to forty-six species and thirty-two genera (Eads, 1950). We were not able specifically to place the flea, either from the literature or our collection and specimens were sent to George P. Holland, Department of Agriculture, Ottawa, Canada, a specialist on the Ceratophyllus. Mr. Holland agreed that the species was new and has been helpful with taxonomnic assistance. A description, with figures, is presented in this paper.

Birds of Kerr County, Texas

HELMUT K. BUECHNER Texas Cooperative Wildlife Research Unit and Department of Fish and Game, Agricultural and Mechanical College of Texas, College Station, Texas. Kerr County appears to be on a dividing line between many eastern and western forms of bird life. It is situated on the Edwards Plateau, which is the southern termination of the Great Plains in central Texas. Approaching from the east, the Edwards Plateau is the abrupt rise in elevation encountered. The rise extends north through central Texas as the so-called first plateau. The change occurs at the Balcones Escarpment, a Cretaceous fault line that extends roughly from Dallas through Waco and Austin to San Antonio, and then westward to Del Rio. Elevations within Kerr County range from 1,000 to 2,300 feet. The topography varies from the level alluvial lands along the Guadalupe River to the hilly lands in the uplands. Drainage is principally by the Guadalupe River and its tributaries, although the Frio, Sabinal, Medina, and South Llano rivers also have their headwaters in the county. The deep alluvial soils of the Guadalupe Valley are utilized for cultivation; the thin limestone soils of the uplands for livestock grazing. River bottoms support heavy stands of cypress, water oak, hackberry, pecan, and walnut; whereas the dry uplands are covered by oak-savannah pastures, cedar brakes, and dense thickets of shinnery oak. The present bird list is based primarily upon specimens in the Texas Cooperative Wildlife Collection at the Agricultural and Mechanical College of Texas, and the following collections as indicated in the United States Fish and Wildlife Service records: Bio-

Lampropeltis triangulum annulata from Kerr County, Texas

Lampropeltis triangulum annulata from Kerr County, Texas

Corrections: The Range Vegetation of Kerr County, Texas, in Relation to Livestock and White-Tailed Deer

Corrections: The Range Vegetation of Kerr County, Texas, in Relation to Livestock and White-Tailed Deer

The Range Vegetation of Kerr County, Texas, in Relation to Livestock and White-Tailed Deer

Introduction 697 Succession -706 The Problem . 697 Segregation 708 Methods of Investigation 698 Principal Vegetative Areas 708 Acknowledgments 698 The Liveoak-Shinoak Divide709 Previous Investigations 699 The Blackjack Divide ----------7-----719 The Liveoak-Spanish Oak Habitat Factors -. ... 699 Erosion Area 724 Climate 699 The Cedar Brakes 729 Physiography -700 The Riparian Community GroupJ732 Soils------------------------------702 Interrelationships of Vegetation, Anthropic Influences -702 Livestock and Deer -734

Elaphe bairdi from Kerr County, Texas

Elaphe bairdi from Kerr County, Texas

Two Species of Cliff Swallows Nesting in Kerr County, Texas

Two Species of Cliff Swallows Nesting in Kerr County, Texas