James C. Kroll

THERMAL ECOLOGY OF ANOLINE LIZARDS: TEMPERATE VERSUS TROPICAL STRATEGIES

Based on field studies of a Texas population, the thermal ecology of the northernmost anole (Anolis carolinensis) is described in terms of mean and preferred body temperatures. Multiple linear regression analyses of mean body temperatures from 37 anole populations show significant positive regressions with ambient light level and latitude, and a significant negative relationship with eleva- tion. We contrast the roles of mean body temperature in adaptive strategies of dis- persal from lowland tropical sites (1) into low temperate latitudes and (2) up tropical mountains. It appears that with dispersal, the behavior patterns which con- trol mean body temperature (i.e., habitat selection and basking) have been readily modified evolutionarily with the result that changes in a whole suite of other life- history characteristics have been minimized.

IMPACT OF WOODPECKER PREDATION ON OVER-WINTERING WITHIN-TREE POPULATIONS OF THE SOUTHERN PINE BEETLE ( Dendroctonus frontalis )

Impact of woodpecker predation on within-tree populations of southern pine beetles ( Dendroctonus frontalis ) was studied during the period November 1975 to February 1976. Exclusion studies indicated that woodpeckers had a significant impact on pupa and brood adult life stages of southern pine beetles (SPB), especially at mid-bole where densities are greatest. Woodpecker foraging activity paralleled increases in insect predator and parasite densities.

Effects of DDE on experimentally poisoned free‐tailed bats [tadarida brasiliensis): lethal brain concentrations

Adult female free-tailed bats (Tadarida brasiliensis) were collected at Bracken Cave, Texas, and shipped to the Patuxent Wildlife Research Center. Treated mealworms (Tenebrio molitor) containing 107 ppm DDE were fed to 17 bats; five other bats were fed untreated mealworms. After 40 days on dosage, during which one dosed bat was killed accidentally, four dosed bats were frozen and the remaining 17 were starved to death. The objective was to elevate brain levels of DDE to lethality and measure these concentrations. After the feeding period, dosed bats weighed less than controls. After starvation, the body condition of dosed bats was poorer than that of controls even though there was no difference in the amounts of carcass fat. During starvation, dosed bats lost weight faster than controls. Also, four dosed bats exhibited the prolonged tremoring that characterizes DDE poisoning. DDE increased in brains of starving bats as fat was metabolized. The estimated mean brain concentration of DDE diagnostic of death was 519 ppm with a range of 458-564 ppm. These values resemble diagnostic levels known for two species of passerine birds, but they exceed published levels for two free-tailed bats from Carlsbad Caverns, New Mexico.

Juvenile-to-Adult Antler Development in White-Tailed Deer in South Texas

Abstract Past studies using penned deer provide conflicting results on the age when reliable predictions about antler growth potential in white-tailed deer (Odocoileus virginianus) can be made. We captured wild whitetail males via aerial net gun on 12 ranches in 5 counties in south Texas, USA, from 1999 to 2007 to determine if a reliable juvenile-to-adult relationship in antler development existed. We individually marked and released captured animals at the trap site after we took antler and body measurements. We recaptured marked animals as possible in subsequent years or until we obtained final measurements after legal harvest. Amount of growth in the first set of antlers in whitetail males was a poor predictor of antler growth at maturity. By 4.5 years of age there were no differences (P > 0.05) in antler measurements regardless of the amount of development of the first set of antlers at 1.5 years. We concluded culling of yearling males based on number of antler points would have little positive effect on overall antler quality in future years.

Radiotelemetry for Studying Thermoregulation in Free‐Ranging Snakes

A design for a treatment capable of relaying core temperatures from free—ranging snakes is presented. The transmitter consists of a pulse generator, switch, RF oscillator, and antenna. The completed system is compacted, encapsulated in paraffin and latex, and force—fed to the snake. The transmitter weighs approximately 15 gm, and our models have operated for as long as two months on two 1.35—v cells. Maximum transmission distance observed was 210 m (taken as the point where the signal was first detected across open terrain) from within a snakes body. See full-text article at JSTOR

Using Infrared-Triggered Cameras to Monitor Activity of Forest Carnivores

Abstract The activity patterns of 4 forest predator species were monitored, using infrared-triggered cameras, within a 1318-ha study area in East Texas. We recorded 161 photographic capture events in 1925 trap-nights over 17 weeks. Photographic capture events included 18 Lynx rufus (Bobcat), 109 Procyon lotor (Raccoon), 21 Didelphis virginiana (Virginia Opossum), and 13 Canis latrans (Coyote). We developed an easily replicated method of measuring time on a percent scale to compare activity data over several months, accounting for changes in sunrise and sunset times. Bobcat activity was 38.9% crepuscular and 22.1% diurnal. The activity of the other 3 species was mostly nocturnal: Raccoon 94.5%, Virginia Opossum 100%, and Coyote 77%. Moon phase based on percentage of visible light did not affect either Raccoon or Virginia Opossum nocturnal activity level.

A Computer Based Data File Management System for Telemetry Studies on Free Ranging Animals

Telemetry studies on free ranging animals quickly generate large quantities of location data which are often difficult to analyze. A computer based data file management system, based on a modification of the Statistical Package for the Social Sciences, was developed for acquisition, update and analyses of such data. Field data are recorded directly on a miniature remote data terminal, eliminating need for field data forms and verification. Location coordinates are subsequently plotted by a computer program interfaced with the Tectronix remote terminal. Time elapsed from data acquisition to update and/or analyses is less than 24 h.

White-Tailed Deer Antler Research: A Response to Demarais and Strickland

Abstract Demarais and Strickland presented several questions about the scope and validity of conclusions regarding predictability of mature antler size based on yearling antler size and produced a simulation model reported to demonstrate measurement bias in our 2008 study. We believe our conclusions were appropriate with our research hypothesis and demonstrated the assumed differential selection bias by hunters used in Demarais and Strickland was unwarranted. Demarais and Strickland provided no metadata to document the provenance of data used in their model and did not account for location, year, cohort, nutrition of research animals, or loss of individuals from their sample population by accidents or death: the same questions raised in their critique. Additionally, selection and experimental design problems in a portion of their sample population indicate their model results are questionable. Our responses to Demarais and Strickland will aid wildlife managers in making future culling decisions in white-tailed deer management.