Coyotes: Friends or Foe of Northern Bobwhite in Southern Texas

Food habits of 407 coyotes (Canis latrans), intermittently collected in southern Texas from March 1994 to January 1997, were determined from coyote stomachs. Mammalian prey was the most prevalent diet item as calculated by frequency of occurrence and aggregate percent methods, followed by insects, vegetation, birds, and reptiles. The remains of northern bobwhite (Colinus virginianus) or their eggs were found in only 12 coyote stomachs, which constituted 1% of the coyote diet as calculated by the aggregate percent method. Northern bobwhite appear to be an incidental prey item for coyotes in southern Texas. Therefore, coyote removal programs designed to lessen quail depredation appear unwarranted

Use of Passive Integrated Transponders in Hatchling Texas Horned Lizards

The Texas horned lizard (Phrynosoma cornutum) is a Texas state-threatened species and acquisition of data related to the species\u27 ecology is essential. To accomplish this task individual animals need to be marked. Many marking techniques are available for lizards, however the majority of techniques have been tested on adults only. Studies involving hatchling and juvenile horned lizards are scarce due to problems associated with marking and relocating individuals in these age classes. I demonstrated that injection of passive integrated transponders (PIT\u27s) can safely be used as a marking method in young Texas horned lizards. Thirty-two captive bred hatchling lizards were used. Hatchlings were allowed to grow to 20 mm snout-vent length (SVL) before PIT\u27s were inserted into 16 hatchlings while the other 16 hatchlings were used as control animals. Hatchlings were measured and weighed weekly for 14 weeks and blood samples obtained weekly for 3 weeks to assess if PIT\u27s affected lizard growth and health. No differences were noted in treatment effects for SVL (F1450 = 0.85, P = 0.37), weight (F1,450 = 1.60, P = 0.22), or white blood cell and differential counts (F1,30 \u3c 1.47, P \u3e 0.23). However, an interaction between treatment and week occurred (F I4.450 = 1.79, P = 0.04) for SVL. Texas horned lizard hatchlings that were PIT-tagged were larger in SVL during weeks 3, 7 to 10, and 12 than control lizards. No ditferences in SVL were noted between treatment groups during the remaining weeks. A duration effect was noted for both SVL (F 14,450 = 7654.0, P = 0.0001) and mass (F14,450 = 1595.1, P = 0.000 I). Snout-vent length for both PIT-tagged and control lizards increased weekly until week 12 when growth rate began to slow down. Mass gain for both groups of lizards was similar, with weekly spurts occurring except between weeks 0 and 1,7 and 8, 12 and 13, and 13 and 14. Passive integrated transponders did not interfere with the growth or health of young Texas horned lizards; therefore, they can be safely used as a marking tool

Chilabothrus subflavus

Number of pages = 30Geological SciencesIntegrative Biolog

Holiday Lights Create Light Pollution and Become Ecological Trap for Eastern Fox Squirrels: Case Study on a University Campus

Ecological light pollution is now recognized as a significant source of ecosystem alteration. We documented that holiday lights are a seasonal source of light pollution that constitute an ecological trap for eastern fox squirrels (Sciurus niger). Texas A&M University-Kingsville (TAMUK) wildlife students surveyed a 2-km walking transect 5 times per month each month for the relative abundance and diel behavior of eastern fox squirrels and feral cats (Felis catus) on the TAMUK campus during 2018–2019. Eastern fox squirrels exhibited diurnal behaviors throughout the year but extended their foraging behavior nearly 4 hours after sunset with the addition of holiday lights. Feral cats and owls (Strigiformes) exhibited diurnal and nocturnal behaviors but conducted the majority of their hunting during crepuscular hours. We documented that monthly squirrel mortality increased 7-fold with the addition of holiday lights, possibly due to the extension of foraging time by squirrels. Although seasonal lighting is intended to be festive for humans, it can have negative consequences for eastern fox squirrels. Educating the public concerning the issue of light pollution on wildlife species is needed because the majority of the public appears unaware that bright lights can negatively alter wildlife behaviors. Reducing light intensity by either using less outdoor lights or perhaps using colored lights rather than clear white bulbs may lessen the negative effect on foraging behavior of squirrels

Testing the Value of Prickly Pear Cactus as a Nest-Predator Deterrent for Northern Bobwhite

Recent research indicates that northern bobwhites (Colinus virginianus) in Texas commonly nest in prickly pear cactus (Opuntia sp.) instead of conventional bunchgrass habitat. We hypothesized that bobwhites nested in prickly pear because it served as a deterrent to nest predators thereby increasing probability of nest success (nest-protection hypothesis; Slater et al. 2001). We experimentally tested the nest-protection hypothesis by providing 50 wild-caught, captive raccoons (Procyon lotor) with combinations of simulated, bobwhite nests. Nest combinations included either 1 nest in bunchgrass (e.g., little bluestem [Schizachryium scoparium]) and 1 nest in prickly pear cactus (partial [75%] or full [100%] protection), or 2 separate nests in prickly pear (partial and full protection). Raccoons depredated 97%, 33%, and 14% of simulated nests constructed of bunchgrass (n = 35 nests), partial protection prickly pear (n = 30 nests), and full protection prickly pear (n = 35 nests), respectively. Prickly pear nests that provided full protection exhibited better survival against raccoon depredation than other nest types. Our study provides support for the nest-protection hypothesis regarding why northern bobwhite possibly nest in prickly pear cactus

Do You Hear What I Hear? Human Perception of Coyote Group Size

Recordings of 1 – 4 coyotes (Canis latrans) that were howling and yip-yapping were played to 427 participants who were asked to estimate the number of coyotes they perceived to hear. Participants were separated by gender (M or F), age group ( 35), resident location (urban, suburban, or rural), and occupation type (rancher/farmer or non-rancher/farmer). Differences between participants concerning gender, age group, resident location, and occupation type were not observed; however, treatment differences were observed. Participants were able to discern differences in the number of coyotes howling with the addition of each coyote; however, participants consistently overestimated the number of coyotes they heard by nearly 2-fold. Thus, it seems the general public has the perception that coyotes are more abundant than they actually are

A Method for Determining Asymptotes of Home-Range Area Curves

Home-range area curves are used to estimate the number of locations needed to accurately estimate home range size based on the asymptote of the curve. However, the current methodology used to identify asymptotes for home-range area curves is largely subjective and varies between studies. Our objective was to evaluate the use of exponential, Gompertz, logistic, and reciprocal function models as a means for identifying asymptotes of home-range area curves. We radio monitored northern bobwhite (Colinus virginianus) coveys during mid-September through November 2001-2002 in Jim Hogg County, Texas. We calculated home-range size of radiomarked coveys using the 95% fixed kernel with least squares cross validation and minimum convex polygon estimators. We fitted area observations and coefficient of variation to the number of locations using exponential, Gompertz, logistic, and reciprocal function models to estimate the minimum number of locations necessary to obtain a representative home range size for each home range estimator. The various function models consistently provided a relatively good fit for home range area curves and coefficient of variation curves (0.58 ≤ R2 0.99; P \u3c 0.05) for both home range estimators. We used an information-theoretic framework (AICC) to select the best model to estimate area-curve asymptotes. The use of function models appears to provide a structured and useful approach for calculating area-curve asymptotes. We propose that researchers consider the use of such models when determining asymptotes for home-range area curves and that more research be conducted to validate the strength of this method

Efficacy of an Online Native Snake Identification Search Engine for Public Use

Visual methods of species identification are used both in research and recreational contexts because they are inexpensive, non-invasive, and believed to be effective among uniquely identifiable individuals. We examined the ability of the general public to identify live snakes (Serpentes) that are native to the United States using an online snake identification search engine (SISE) produced by the North America Brown Tree Snake Control Team (NABTSCT) website, http://www.nabtsct.net. The SISE consisted of participants answering 7 descriptive questions concerning a snake and then reviewing photographs of snakes that matched that description. Using 3 species of snakes native to Texas, USA, 21% of 395 participants were able to correctly identify all of the snakes using the online SISE, 54% correctly identified 2 snakes, 18% correctly identified 1 snake, and only 7% could not identify any snakes. Participants identified the distinctly marked checkered garter snake (Thamnophis marcianus) more readily (87% of participants) than the gopher snake (Pituophis catenifer) and Trans-Pecos rat snake (Bogertophis subocularis; 55% and 46% of participants, respectively). The probability of participants correctly identifying a snake using the online SISE increased substantially if ≥4 of the 7 descriptive questions were answered correctly. The age of participants and affinity toward snakes affected participant ability to correctly answer questions about snake morphology and identify snakes. In general, participants who displayed fear of snakes were less likely to correctly identify snake species than those who expressed a snake-neutral or enthusiast attitude. Additionally, younger participants performed better, on average, than older participants. Most participants (97%) claimed they would be able to use the online SISE to correctly identify other snakes in the future. We believe the public can use the online SISE to identify snakes, and hence, it can be an educational tool for the public to learn about an often neglected wildlife suborder

Cost–Benefit Analysis of Coyote Removal as a Management Option in Texas Cattle Ranching

The monetary value of livestock losses attributed to coyote (Canis latrans) predation in North America has increased during the past 20 years. In Texas, USA alone in 2011, these loses were estimated at $6.9 million. To mitigate coyote-related livestock losses, several lethal and nonlethal control methods have been developed. However, there remains a need for better information to guide management decisions regarding cost-effective predator control strategies for livestock production systems. We acquired data, which was used in the model, from published literature from 1960 to present day, subject matter experts, and anecdotal information on coyote ecology. We developed a systems dynamics simulation model to evaluate the economic impact of coyote control on an average-sized cattle (Bos spp.) operation (1,000 ha) for a conceptual 10-year period in Texas. We conducted a sensitivity analyses to validate the model and identify the most sensitive parameters. We tested 88 scenarios using common coyote management methods (i.e., aerial gunning, M-44 devices, snares, livestock guard animals (LGAs), calling and shooting, and foothold traps), combinations of multiple management methods, and number of applications per year (once per year, twice per year, continuous). Several management methods were cost effective at reducing calf predation when applied sparingly and under assumptions of skillful and dedicated application of coyote control methods. The most cost-effective method of coyote control to reduce calf depredation was the combined use of snares and LGAs. When applied 1 month prior to the primary calving month, the snare/LGA combination showed an 81% decrease in overall costs of calf loss and predator management during the 10-year period, respectively. Cost effectiveness of methods deteriorated as the number of applications per year increased. While these are useful results, the intangible values of coyotes through grazing benefits (i.e., fewer prey species such as lagomorphs on the landscape to compete for forage with cattle) and ecological benefits (i.e., mitigation of meso-predator release) were not included in the model. However, these benefits should be considered by ranchers before implementing lethal coyote management

Examining a potential brown treesnake transport pathway: shipments from Guam

Shipments of cargo and household goods have been identified as pathways for brown treesnake (Boiga irregularis) transport from Guam to other locations. We analyzed data regarding shipments of military household goods leaving Guam during 2006 to 2009 to identify the potential for human transport of brown treesnakes to the United States by determining when shipments most commonly occur and identifying primary receiving areas. We found that the number of shipments was highest during the months of May and June and that California receives more shipments (23% of total shipments) than any other location. Approximately 98% of shipments originated from the U.S. Navy and U.S. Air Force, with naval shipments increasing over time. Guam is currently undergoing a military buildup during which shipments are expected to increase, suggesting the need for increased vigilance and prioritization of inspection efforts