Masticophis Flagellum Research Articles

Spatiotemporal Patterns of Snake Captures and Activity in Upland Pine Forests

Patterns of species' occurrences across space and time are fundamental components to understanding their ecology, as this variation often reflects responses to local environmental gradients. We built species-specific models to understand the spatial and temporal factors predicting captures and activity of five snake species in upland pine forests: copperhead (Agkistrodon contortrix), racer (Coluber constrictor), coachwhip (Masticophis flagellum), western ratsnake (Pantherophis obsoletus), and western ribbonsnake (Thamnophis proximus). From mid-May to mid-July across 3 y (2018, 2019, 2020), we monitored boxtraps in two upland pine forests experiencing different management regimes: (1) subjected to frequent thinning and prescribed burning, and (2) subjected to infrequent thinning and prescribed burning. Significantly more copperheads and western ribbonsnakes were captured at the infrequently thinned and burned forest, whereas significantly more racers were captured at forest subjected to frequent thinning and burning. As the summer progressed, captures decreased each subsequent month for both racers and western ratsnakes, with the fewest captures in July. Western ratsnakes were the only species to exhibit a response to the weather in that activity decreased with increasing rainfall. No variables were significant predictors of coachwhip captures. The variation in captures across space may be attributed to the physiological tolerances of each species based on their habitat preferences or differences in prey availability at each forest. Interactions between the physiological tolerances, foraging behaviors, or their reproductive phenology may be underlying the temporal variation in activity patterns.

Ophiophagous Combatants: Predation on a Kingsnake (Lampropeltis sp.) by a Coachwhip (Coluber flagellum) in the Sonoran Desert

Ophiophagous Combatants: Predation on a Kingsnake (Lampropeltis sp.) by a Coachwhip (Coluber flagellum) in the Sonoran Desert

The influence of prescribed fire on site selection in snakes in the longleaf pine ecosystem

Prescribed fire is an essential tool for the restoration and maintenance of the longleaf pine (Pinus palustris) ecosystem. This type of management benefits wildlife species that are frequently associated with open canopy pine forests in the Southeastern U.S., including upland snakes. But few studies have examined the long term effects of prescribed fire (i.e., fire frequency over time) on snake occurrences at local and landscape scales. Likewise, comprehensive data are lacking on the response of snakes to individual prescribed burns (i.e., how long after a fire does a snake occupy a location). To investigate snake responses to these two factors, we used radio-telemetry data for five species of snakes, including three species of open-canopied forest specialists and two species that occur more broadly in upland forests (i.e., generalists), on a large site managed with prescribed fire. We hypothesized that open-canopied forest specialists, eastern diamondback rattlesnake (Crotalus adamanteus), Florida pine snake (Pituophis melanoleucus), and eastern coachwhip (Coluber flagellum) would select more frequently burned locations over less frequently burned locations and would occupy locations sooner after a fire than generalist species, eastern kingsnake (Lampropeltis getula) and gray ratsnake (Pantherophis allegheniensis). We used spatial data collected from previous snake radio-telemetry studies conducted over a nine year period (2003–2012) and annual burn data from 1994 to 2012. We used compositional analysis to evaluate snake use (selection) versus availability of locations based on fire frequency at different spatial scales (home range and landscape). As predicted, open-canopied forest specialists selected locations with more frequent fire (≤2.5 y return interval) significantly more often than locations with less frequent fire (≥3.3 y return interval; F7, 18 = 9.06, p < 0.0001). Whereas habitat generalists selected locations with fires across a broader spectrum of frequencies (every 2–10 y) significantly more often than locations that were not burned in 10 years (no burn) or those burned most frequently (1.4 y return interval; F7, 21 = 5.94, p < 0.001). The three open-canopied forest specialists, as well as the generalist, eastern kingsnake, predominantly used locations within two years after a burn (eastern diamondback rattlesnake, 81% of locations; Florida pine snake, 91% of locations; eastern coachwhip, 98% of locations; and eastern kingsnake, 91% of locations. The generalist, grayrat snake, selected locations where time since burn was less than two years (53.8% of locations), as well as, locations that had not been burned in 10 years (23.5%). Our data suggest that forest management programs that include prescribed fire with short burn return intervals (<3 y) over long time periods would benefit both open-canopied forest specialists and generalist snake species that use open-canopied forests.

Effects of urbanization and habitat composition on site occupancy of two snake species using regional monitoring data from southern California

Detection data from a regional, reptile-monitoring program conducted by the U.S. Geological Survey were analyzed to understand the effects of urbanization and habitat composition on site occupancy of the coachwhip (Masticophis flagellum) and striped racer (M. lateralis) in coastal southern California. Likelihood-based occupancy models indicated striped racers responded to habitat composition, favoring scrub-dominated sites. Coachwhips also responded to habitat composition, favoring open habitats. However, unlike racers, coachwhip spatial population dynamics were strongly associated with the fragmentation and isolation of natural areas caused by urbanization. The odds of coachwhips occupying a site were 64 times greater in large connected areas than the most urbanized and fragmented sites. For coachwhips within urbanized and fragmented sites, the odds of extinction were 10 times greater and odds of colonization were five times lower than in large connected sites. Observed differences between the species in habitat use and specificity are supported by telemetry studies and corroborate existing knowledge of historical patterns of occurrence within the region. Movement data on the coachwhip and striped racer indicate the coachwhip is a wider-ranging species with a greater propensity to encounter roads and other edge environments. Collectively, the results suggest there is widespread loss of the coachwhip from the region, and that long-term persistence of remaining populations is dependent on metapopulation dynamics. The substantially different response of the two species to land-use change serves as a caution against the casual use of closely related species as surrogates in the development of species-specific conservation plans.

More than meets the eye: change in pupil shape by a mock viper

More than meets the eye: change in pupil shape by a mock viper

Spatial Ecology and Habitat Use of the Coachwhip in a Longleaf Pine Forest

Abstract We examined spatial ecology and habitat use of Coluber flagellum (Coachwhip) in a 12,000-ha Pinus palustris (Longleaf Pine) reserve in southwestern Georgia from 2007 through 2008. We radio-tracked 7 Coachwhips (5 males and 2 females) for 291 to 325 days. The average 100% minimum convex polygon (MCP) home-range for all snakes was 102.9 ± 28 ha. Daily movement during the active season (April–November) varied from 28.6 to 73.6 m for males (n = 5) and from 27.5 to 95.6 m for females (n = 2). Snakes were usually associated with open-canopied pine forests and found less often in aquatic and agricultural habitats. Our results are consistent with evidence from previous studies in that Coachwhips used sites with open-forest structure and large expanses of habitat.

A new species of Isospora (Apicomplexa: Eimeriidae) from eastern coachwhip, Coluber flagellum flagellum (Reptilia: Ophidia) from Oklahoma.

Between June 2013 and August 2014, four eastern coachwhips, Coluber flagellum flagellum were collected from Arkansas (n = 2) and Oklahoma (n = 2) and their faeces examined for coccidian parasites. One (25%) harboured an isosporan that we describe here as new. Oocysts of Isospora kiamichiensis sp. n. were spheroidal to subspheroidal with a uni-layered wall and measured (length × width, L × W) 25.0 × 22.2 μm, with an L/W ratio of 1.1. A micropyle, oocyst residuum and polar granule were absent. Sporocysts were ovoidal, 13.9 × 9.4 μm, with an L/W ratio of 1.5. A pronounced, button-like Stieda body was present as well as a substieda body. A sporocyst residuum was present as dispersed granules. This is the first isosporan and fourth coccidian reported from eastern coachwhip snakes. In addition, a single oocyst of an unknown choleoeimerian was recovered from this host.

Feeding Ecology of the Snake Community of the Red Hills Region Relative to Management for Northern Bobwhite: Assessing the Diet of Snakes Using Stable Isotopes

Snakes can respond to variation in resource availability through changes in diet and species interactions. For many species, however, patterns of variation in diet are poorly known. Making use of novel 13C, through the provision of supplemental food in the form of milo (Sorghum spp.) for Northern Bobwhite (Colinus virginianus), we used carbon (δ13C) and nitrogen (δ15N) stable isotope analyses to evaluate the specificity of mammalian and herpetofaunal diet, trophic niche width, and trophic niche overlap between five snake species in the Red Hills of the southeastern United States. Most mammalian prey and Northern Bobwhite were characterized by different δ13C values in the milo- and non-milo-treated areas. Using milo to reflect dietary patterns we determined that Coachwhip (Masticophis flagellum), Cottonmouth (Agkistrodon piscivorus), and Eastern Rat Snake (Pantherophis alleghaniensis) were dietary generalists, revealed by larger isotopic range and lack of correspondence between isotopic values and those of distinct prey groups. In contrast, Black Racer (Coluber constrictor) and Corn Snake (Pantherophis guttatus) were dietary specialists. Black Racers fed largely on herpetofauna, and δ13C values of Corn Snake revealed a gradual ontogenetic/size-related diet shift from herpetofauna to a mammalian-based diet. There was considerable overlap of isotopic trophic niche between snake species, except for the Cottonmouth with δ15N values higher than other sampled species. These findings provide novel insight into snake trophic ecology.

Power lines, roads, and avian nest survival: effects on predator identity and predation intensity.

1 Anthropogenic alteration of landscapes can affect avian nest success by influencing the abundance, distribution, and behavior of predators. Understanding avian nest predation risk necessitates understanding how landscapes affect predator distribution and behavior.2 From a sample of 463 nests of 17 songbird species, we evaluated how landscape features (distance to forest edge, unpaved roads, and power lines) influenced daily nest survival. We also used video cameras to identify nest predators at 137 nest predation events and evaluated how landscape features influenced predator identity. Finally, we determined the abundance and distribution of several of the principal predators using surveys and radiotelemetry.3 Distance to power lines was the best predictor of predator identity: predation by brown-headed cowbirds (Molothrus ater), corvids (Corvus sp. and Cyanocitta cristata), racers (Coluber constrictor), and coachwhips (Masticophis flagellum) increased with proximity to power lines, whereas predation by rat snakes (Elaphe obsoleta) and raptors decreased. In some cases, predator density may reliably indicate nest predation risk because racers, corvids, and cowbirds frequently used power line right-of-ways.4 Of five bird species with enough nests to analyze individually, daily nest survival of only indigo buntings (Passerina cyanea) decreased with proximity to power lines, despite predation by most predators at our site being positively associated with power lines. For all nesting species combined, distance to unpaved road was the model that most influenced daily nest survival. This pattern is likely a consequence of rat snakes, the locally dominant nest predator (28% of predation events), rarely using power lines and associated areas. Instead, rat snakes were frequently associated with road edges, indicating that not all edges are functionally similar.5 Our results suggest that interactions between predators and landscape features are likely to be specific to both the local predators and landscape. Thus, predicting how anthropogenic changes to landscapes affect nesting birds requires that we know more about how landscape changes affect the behavior of nest predators and which nest predators are locally important.

INTESTINAL COCCIDIOIDOMYCOSIS IN A RED COACHWHIP SNAKE (MASTICOPHIS FLAGELLUM PICEUS)

An adult female, wild-caught red coachwhip snake (Masticophis flagellum piceus) was euthanized at the Phoenix Zoo due to severe neurologic signs. Necropsy and histopathology revealed an invasive liposarcoma of the vertebral column, which likely caused the neurologic signs. Histology of the small intestine revealed a granuloma with intralesional yeasts morphologically compatible with the genus Coccidioides. The diagnosis of coccidioidomycosis was confirmed with immunohistochemistry staining. Coccidioides posadasii is endemic to Arizona and is an important cause of disseminated fungal infections in mammals in this region. This is the first known report of intestinal coccidioidomycosis in a veterinary species and the second report of coccidioidomycosis in a reptile.

Snake co‐occurrence patterns are best explained by habitat and hypothesized effects of interspecific interactions

Snakes often occur in species-rich assemblages, and sympatry is thought to be facilitated primarily by low diet overlap, not interspecific interactions. We selected, a priori, three species pairs consisting of species that are morphologically and taxonomically similar and may therefore be likely to engage in interspecific, consumptive competition. We then examined a large-scale database of snake detection/nondetection data and used occupancy modelling to determine whether these species occur together more or less frequently than expected by chance while accounting for variation in detection probability among species and incorporating important habitat categories in the models. For some snakes, we obtained evidence that the probabilities that habitat patches are used are influenced by the presence of potentially competing congeneric species. Specifically, timber rattlesnakes (Crotalus horridus) were less likely than expected by chance to use areas that also contained eastern diamond-backed rattlesnakes (Crotalus adamanteus) when the proportion of evergreen forest was relatively high. Otherwise, they occurred together more often than expected by chance. Complex relationships were revealed between habitat use, detection probabilities and occupancy probabilities of North American racers (Coluber constrictor) and coachwhips (Coluber flagellum) that indicated the probability of competitive exclusion increased with increasing area of grassland habitat, although there was some model uncertainty. Cornsnakes (Pantherophis guttatus or Pantherophis slowinskii) and ratsnakes (Pantherophis alleghaniensis, Pantherophis spiloides, or Pantherophis obsoletus) exhibited differences in habitat selection, but we obtained no evidence that patterns of use for this species pair were influenced by current interspecific interactions. Overall, our results are consistent with the hypothesis that competitive interactions influence snake assemblage composition; the strength of these effects was affected by landscape-scale habitat features. Furthermore, we suggest that current interspecific interactions may influence snake occupancy, challenging the paradigm that contemporary patterns of snake co-occurrence are largely a function of diet partitioning that arose over evolutionary time.

The effect of coachwhip presence on body size ofNorthAmerican racers suggests competition between these sympatric snakes

AbstractWhen sympatric species compete, character divergence may help maintain coexistence. Snakes are often found in species‐rich assemblages while exploiting similar resources; because snake body size is a relatively plastic trait that determines the range of prey sizes an individual may consume, divergence in body size between sympatric species may arise as a result of interspecific interactions. TheNorthAmerican racer,Coluber constrictor, and the larger coachwhip,Coluber flagellum, have a close taxonomic relationship and similar foraging strategies. Therefore, we hypothesized thatC. constrictorwould be smaller where they co‐occur withC. flagellum, as compared to whereC. flagellumis absent, throughout the southeastern extent of their range. To evaluate this hypothesis, we obtained data on body size for 2321 adultC. constrictorand 526 adultC. flagellum, along with habitat data and other potentially important factors influencing body size.Coluber constrictorwas smaller than elsewhere when in peninsularFlorida, in pine forests, on hydric soils and in the presence of the larger and potentially competingC. flagellum. Body size ofC. flagellumdid not vary by any measured habitat variables. The trends we documented are consistent with the hypothesis thatC. constrictorbody size is influenced by several variables, including co‐occurrence withC. flagellum.

The Herpetofauna of the Camp Shelby Joint Forces Training Center in the Gulf Coastal Plain of Mississippi

Abstract The Camp Shelby Joint Forces Training Center (CSJFTC) is a 54,315-ha National Guard training installation located in the Piney Woods subprovince of the Gulf Coastal Plain physiographic region of south-central Mississippi. A list of 108 native amphibian and reptile species possibly occurring on the CSJFTC was generated using known geographic distribution ranges and museum records. General herpetofaunal field-collecting techniques were used to survey the CSJFTC's aquatic and terrestrial habitats from April 2004-April 2007. Eighty-three native and one introduced species were identified, comprising 59% of the state's known (excluding marine species) and 77% of the CSJFTC's suspected herpetofauna. Ten species listed as needing special protection by state or federal agencies occur at the site, including Crotalus adamanteus, Gopherus polyphemus, Lampropeltis calligaster, Masticophis flagellum, Micrurus fulvius, Ophisaurus attenuatus, Pituophis melanoleucus, Pseudacris ornata, Pseudotriton ruber, and Reg...

MAsticophis flagellum Selects Florida Scrub Habitat at Multiple Spatial Scales

Abstract The use of space by individual animals strongly influences the spatial extent, abundance, and growth rates of their populations. We analyzed the spatial ecology and habitat selection of Masticophis flagellum (the coachwhip) at three different scales to determine which habitats are most important to this species. Home ranges and mean daily displacements of M. flagellum in Florida were large compared to individuals in other populations of this species. Home ranges contained a greater proportion of Florida scrub habitat than did the study site as a whole, and individuals selected Florida scrub habitat within their home ranges. For both selection of the home range within the study site and selection of habitats within the home range, mesic cutthroat and hydric swamp habitats were avoided. Standardized selection ratios of Florida scrub patches were positively correlated with lizard abundance. Several non-mutually exclusive mechanisms, including foraging success (prey abundance, prey vulnerability, and...

Behavioral Response of the Coachwhip (Masticophis flagellum) to Habitat Fragment Size and Isolation in an Urban Landscape

Habitat fragmentation is a significant threat to biodiversity worldwide. Habitat loss and the isolation of habitat fragments disrupt biological communities, accelerate the extinction of populations, and often lead to the alteration of behavioral patterns typical of individuals in large, contiguous natural areas. We used radio-telemetry to study the space-use behavior of the Coachwhip, a larger-bodied, wide-ranging snake species threatened by habitat fragmentation, in fragmented and contiguous areas of coastal southern California. We tracked 24 individuals at three sites over two years. Movement patterns of Coachwhips changed in habitat fragments. As area available to the snakes was reduced, individuals faced increased crowding, had smaller home-range sizes, tolerated greater home-range overlap, and showed more concentrated movement activity and convoluted movement pathways. The behavioral response shown by Coachwhips suggests, on a regional level, area-effects alone cannot explain observed extinctions on habitat fragments but, instead, suggests changes in habitat configuration are more likely to explain the decline of this species. Ultimately, if ''edge-exposure'' is a common cause of decline, then isolated fragments, appropriately buffered to reduce emigration and edge effects, may support viable populations of fragmentation-sensitive species.

Sympatric Masticophis flagellum and Coluber constrictor Select Vertebrate Prey at Different Levels of Taxonomy

Masticophis flagellum (Coachwhip) and Coluber constrictor (Eastern Racer) are widespread North American snakes with similar foraging modes and habits. Little is known about the selection of prey by either species, and despite their apparently similar foraging habits, comparative studies of the foraging ecology of sympatric M. flagellum and C. constrictor are lacking. We examined the foraging ecology and prey selection of these actively foraging snakes in xeric, open-canopied Florida scrub habitat by defining prey availability separately for each snake to elucidate mechanisms underlying geographic, temporal, and interspecific variation in predator diets. Nineteen percent of M. flagellum and 28% of C. constrictor contained stomach contents, and most snakes contained only one prey item. Mean relative prey mass for both species was less than 10%. Larger C. constrictor consumed larger prey than small individuals, but this relationship disappeared when prey size was scaled to snake size. Masticophis flagellum was selective at the prey category level, and positively selected lizards and mammals; however, within these categories it consumed prey species in proportion to their availability. In contrast, C. constrictor preyed upon prey categories opportunistically, but was selective with regard to species. Specifically, C. constrictor positively selected Hyla femoralis (Pine Woods Treefrog) and negatively selected Bufo quercicus (Oak Toad), B. terrestris (Southern Toad), and Gastrophryne carolinensis (Eastern Narrowmouth Toad). Thus, despite their similar foraging habits, M. flagellum and C. constrictor select different prey and are selective of prey at different levels of taxonomy.

Chemosensory cues associated with snake predators affect locomotor activity and tongue flick rate in the whiptail lizard, Aspidoscelis dixoni Scudday 1973 (Squamata Teiidae)

The unisexual teiid lizard Aspidoscelis dixoni Scudday 1973 is shown experimentally to be capable of detecting and responding to chemosensory stimuli from three species of naturally-occurring sympatric predatory snakes (Masticophis flagellum, M. taeniatus, Arizona elegans) and to discriminate these stimuli from those associated with a non-predatory snake (Leptotyphlops humilis segregus), as well as controls (water and cologne). Each lizard was exposed separately to the following: chemical stimuli from each of the predatory snakes, non-predatory, snake, water control, or pungency control (cologne). Lizards were placed in a test chamber whose floor was divided into 4 square grids of equal size, and for each trial, the number of times that a grid was crossed (locomotor activity), the number of tongue flicks observed (tongue flick rate, TFR), and time from beginning of trial to first tongue flick (latency), were recorded. Lizards crossed grid lines at significantly higher rates when exposed to chemosensory cues associated with all predatory snake species as compared to activity in the presence of nonpredator snake cues, water or cologne. There were no differences in number of grid crossings elicited by any of the three predatory snakes. TFR differed significantly among all treatments, but no significant difference was found among lizards exposed to water, cologne, or cues associated with L. h. segregus. TFRs were significantly higher, and latencies significantly lower, when lizards were exposed to chemosensory cues associated with predatory snake. Results suggest that because all lizards had no prior experience with any of the snakes, their ability to detect and respond to chemosensory cues of predators must be innate.

Spatial Ecology of the Coachwhip, Masticophis flagellum (Squamata: Colubridae), in Eastern Texas

We radio-tracked nine Masticophis flagellum (Coachwhips) to determine home range, habitat use, and movements in eastern Texas from April to October 2000. Home ranges of Coachwhips contained more oak savanna macrohabitat than early-successional pine plantation or forested seep, based on the availability of these three macrohabitats in the study area. Likewise, within their individual home ranges, Coachwhips used oak savanna more than the other two macrohabitats, based on availability. An analysis of microhabitat use revealed that, relative to random sites within their home range, Coachwhips were found at sites with fewer pine trees and more herbaceous vegetation taller than 30 cm. Results of the two analyses, macrohabitat and microhabitat, were consistent: oak savannas contained relatively few pine trees but much herbaceous vegetation taller than 30 cm. Coachwhips made frequent long-distance moves, which resulted in large home ranges. Core activity areas, however, were small. These core activity areas were always within the oak savanna macrohabitat. Long movements, large home ranges, and small core activity areas likely were a result of the preferred oak savanna macrohabitat being patchily distributed in the landscape.

Behavioural complexity and prey-handling ability in snakes: gauging the benefits of constriction

Summary Complexity is an important component of behaviour, but is rarely defined or quantitatively analyzed. We tested the hypothesis that complex behaviours are functionally superior to simpler behaviours. We generated complexity values for prey-handling behaviours used by snakes based on a count of behavioural acts, coordination among acts, and the amount of the snake’s body used to subdue prey. We then compared prey-handling ability between species that differed in the complexity of behaviour used to subdue mice (Mus musculus). Corn and ratsnakes (Pantherophis guttata and P. obsoleta) always constricted mice while coachwhips (Masticophis flagellum) used simpler behaviours including jaw hold and body pinning. The constrictors required fewer strikes, less time to capture and subdue mice, and killed prey more quickly than did the coachwhips. Both jaw holding and constriction resulted in severe compression of the prey, but during constriction force is exerted at many points around the prey, while using the jaws limits force exertion to two opposing surfaces. Constriction divides the tasks of seizure and subjugation between the snake’s head and body, thus reducing the number of tasks the jaws must perform. Our results support the idea that constriction is an adaptation for subduing vigorously struggling prey.

Video identification of predators at Golden-cheeked Warbler nests

Abstract We monitored 67 Golden-cheeked Warbler (Dendroica chrysoparia) nests with infrared video cameras and time-lapse recorders to identify predators. Rat snakes (Elaphe spp.) were the most frequent predators, depredating 12 nests and capturing three adult females. A variety of avian predators depredated seven nests, including three American Crows (Corvus brachyrynchos), two Brown-headed Cowbirds (Molothrus ater), one Western Scrub-Jay (Aphelocoma californica), and one Cooper's Hawk (Accipiter cooperii). Fox squirrels (Sciurus niger) depredated four nests and were the only mammalian predators recorded. Post-outcome recordings (i.e., after young fledged or nests failed) revealed western coachwhips (Masticophis flagellum testaceus), mice (Peromyscus sp.), and Greater Roadrunners (Geococcyx californianus) as potential predators, though they were not recorded at active nests. Video proved to be an effective method of monitoring Golden-cheeked Warbler nests, because all but one predator was identified and o...