We present the results of an amphibian and reptile inventory conducted in 1997-1998 at Petrified ... more We present the results of an amphibian and reptile inventory conducted in 1997-1998 at Petrified Forest National Park. Using visual encounter surveys, pitfall trapping, artificial cover boards, and night driving techniques, we recorded 1,628 indi-vidual amphibians and reptiles (exclusive of larval amphibians) of 23 species. The species total includes seven amphibians, nine lizards, and seven snakes. Two of the lizard species (both of them whiptail lizards, genus Cnemidophorus) are new to the park. Small popula-tions of the little striped whiptail are the first records for Petrified Forest, and also the first reported occurrences in Navajo and Apache counties. The New Mexico whiptail (probably introduced) is the first report for the state of Arizona. Petrified Forest National Park has a diverse herpetofauna, with species from varied biogeographic regions (Great Plains, Great Basin, and southern deserts and grasslands) occurring together in the park. The park is one of the few remaini...
We conducted intensive fieldwork in Arizona during 2007-2008 and follow-up work in 2009-2010 to d... more We conducted intensive fieldwork in Arizona during 2007-2008 and follow-up work in 2009-2010 to develop and assess hypotheses to understand population status of the narrow-headed gartersnake (Thamnophis rufipunctatus, THRU). We worked with collaborators in New Mexico Department of Game and Fish to conduct complementary fieldwork and assisted with THRU surveys conducted by Gila National Forest, both in New Mexico. We used transect surveys, trapping, mark-recapture, and habitat measurement to obtain measures of abundance, injury frequency, and demographic status for THRU; abundance of its primary food base of fishes and of potentially impacting species; and habitat quality. Study areas focused at Oak Creek and Black River, with additional intensive work in lower Blue River, all in Arizona. We collected additional data in other parts of Blue River, AZ, and San Francisco Hot Springs and Whitewater Creek, NM. Study sites spanned the range of species status from intact to recently declini...
To assess whether urbanization influences the spatial ecology of a rare and protected venomous re... more To assess whether urbanization influences the spatial ecology of a rare and protected venomous reptilian predator, the Gila monster Heloderma suspectum, we compared home range (HR) size and movement parameters at three sites varying in degree of urbanization in the Sonoran Desert. We predicted that the urban population of H. suspectum would exhibit smaller HRs, avoid human structures and show less movement. Multivariate analysis indicated that males generally exhibited larger HRs and had higher movement rates and activity levels than females at all three sites. Contrary to our predictions, however, HR size and movement parameters did not vary across the sites in relation to the level of urbanization. At the urban site, individuals often crossed narrow roads and regularly used artificial structures as refuges for extended periods. Furthermore, the population sex ratio at the urban site was female-biased, consistent with the expectation that occupation of larger HRs and higher movement rates results in higher mortality for males in urbanized areas. Gila monsters did not appear to alter certain aspects of their spatial ecology in response to low levels of human activity but additional work will be required to assess population viability and possible effects in the long term and with higher levels of urbanization.
ABSTRACT Intentional provisioning of food and water at specific locations, commonly bird feeders ... more ABSTRACT Intentional provisioning of food and water at specific locations, commonly bird feeders and bird baths, may alter bird and mammal abundance, distribution, and recruitment; yet no studies have examined the indirect effects of resource supplementation on terrestrial reptilian mesopredators such as rattlesnakes. In the southwestern deserts of North America, anecdotal evidence suggests provisioning birds with food and water attracts rattlesnakes to exurban yards, either indirectly by increasing prey availability or directly through attraction to water. We conducted the first experimental test of this hypothesis by providing bird seed, water, or bird seed and water at 2 national monuments in Arizona, USA, and followed the responses of adult western diamond-backed rattlesnakes (Crotalus atrox) equipped with radiotransmitters, and endothermic prey species, primarily rodents, birds, and lagomorphs. We found differing responses among prey taxa to supplemental food and water provisioning: rodents showed no response to any treatment, birds responded to food treatments, and lagomorphs responded to water treatments. Overall, spatial responses by adult rattlesnakes were weak, but several subjects appeared to respond to individual treatment grids. We did not find evidence of a direct response by rattlesnakes to supplemental water. Overall, we found little support for the prevalent belief that food and water sources at provisioning stations increase local concentrations of rattlesnakes; we provide several explanations for this counter-intuitive result. 2015 The Wildlife Society.
KEY WORDS Arizona, artificial waters, birds, Crotalus atrox, lagomorph, nuisance wildlife, small mammal, resource supplementation.
Mitigation translocation of nuisance animals is a commonly used management practice aimed at reso... more Mitigation translocation of nuisance animals is a commonly used management practice aimed at resolution of human-animal conflict by removal and release of an individual animal. Long considered a reasonable undertaking, especially by the general public, it is now known that translocated subjects are negatively affected by the practice. Mitigation translocation is typically undertaken with individual adult organisms and has a much lower success rate than the more widely practiced conservation translocation of threatened and endangered species. Nonetheless, the public and many conservation practitioners believe that because population-level conservation translocations have been successful that mitigation translocation can be satisfactorily applied to a wide variety of human-wildlife conflict situations. We reviewed mitigation translocations of reptiles, including our own work with 3 long-lived species (Gila monsters [Heloderma suspectum], Sonoran desert tortoises [Gopherus morafkai], and western diamond-backed rattlesnakes [Crotalus atrox]). Overall, mitigation translocation had a low success rate when judged either by effects on individuals (in all studies reviewed they exhibited increased movement or increased mortality) or by the success of the resolution of the human-animal conflict (translocated individuals often returned to the capture site). Careful planning and identification of knowledge gaps are critical to increasing success rates in mitigation translocations in the face of increasing pressure to find solutions for species threatened by diverse anthropogenic factors, including climate change and exurban and energy development.
abstract. We examined the relationship between insolation, climate, and hibernacula of black-tail... more abstract. We examined the relationship between insolation, climate, and hibernacula of black-tailed (Crotalus molossus), Great Basin (Crotalus lutosus), and western diamondback (Crotalus atrox) rattlesnakes at 4 sites in Arizona, Nevada, and Utah, Hibernacula were ...
We present the results of an amphibian and reptile inventory conducted in 1997-1998 at Petrified ... more We present the results of an amphibian and reptile inventory conducted in 1997-1998 at Petrified Forest National Park. Using visual encounter surveys, pitfall trapping, artificial cover boards, and night driving techniques, we recorded 1,628 indi-vidual amphibians and reptiles (exclusive of larval amphibians) of 23 species. The species total includes seven amphibians, nine lizards, and seven snakes. Two of the lizard species (both of them whiptail lizards, genus Cnemidophorus) are new to the park. Small popula-tions of the little striped whiptail are the first records for Petrified Forest, and also the first reported occurrences in Navajo and Apache counties. The New Mexico whiptail (probably introduced) is the first report for the state of Arizona. Petrified Forest National Park has a diverse herpetofauna, with species from varied biogeographic regions (Great Plains, Great Basin, and southern deserts and grasslands) occurring together in the park. The park is one of the few remaini...
We conducted intensive fieldwork in Arizona during 2007-2008 and follow-up work in 2009-2010 to d... more We conducted intensive fieldwork in Arizona during 2007-2008 and follow-up work in 2009-2010 to develop and assess hypotheses to understand population status of the narrow-headed gartersnake (Thamnophis rufipunctatus, THRU). We worked with collaborators in New Mexico Department of Game and Fish to conduct complementary fieldwork and assisted with THRU surveys conducted by Gila National Forest, both in New Mexico. We used transect surveys, trapping, mark-recapture, and habitat measurement to obtain measures of abundance, injury frequency, and demographic status for THRU; abundance of its primary food base of fishes and of potentially impacting species; and habitat quality. Study areas focused at Oak Creek and Black River, with additional intensive work in lower Blue River, all in Arizona. We collected additional data in other parts of Blue River, AZ, and San Francisco Hot Springs and Whitewater Creek, NM. Study sites spanned the range of species status from intact to recently declini...
To assess whether urbanization influences the spatial ecology of a rare and protected venomous re... more To assess whether urbanization influences the spatial ecology of a rare and protected venomous reptilian predator, the Gila monster Heloderma suspectum, we compared home range (HR) size and movement parameters at three sites varying in degree of urbanization in the Sonoran Desert. We predicted that the urban population of H. suspectum would exhibit smaller HRs, avoid human structures and show less movement. Multivariate analysis indicated that males generally exhibited larger HRs and had higher movement rates and activity levels than females at all three sites. Contrary to our predictions, however, HR size and movement parameters did not vary across the sites in relation to the level of urbanization. At the urban site, individuals often crossed narrow roads and regularly used artificial structures as refuges for extended periods. Furthermore, the population sex ratio at the urban site was female-biased, consistent with the expectation that occupation of larger HRs and higher movement rates results in higher mortality for males in urbanized areas. Gila monsters did not appear to alter certain aspects of their spatial ecology in response to low levels of human activity but additional work will be required to assess population viability and possible effects in the long term and with higher levels of urbanization.
ABSTRACT Intentional provisioning of food and water at specific locations, commonly bird feeders ... more ABSTRACT Intentional provisioning of food and water at specific locations, commonly bird feeders and bird baths, may alter bird and mammal abundance, distribution, and recruitment; yet no studies have examined the indirect effects of resource supplementation on terrestrial reptilian mesopredators such as rattlesnakes. In the southwestern deserts of North America, anecdotal evidence suggests provisioning birds with food and water attracts rattlesnakes to exurban yards, either indirectly by increasing prey availability or directly through attraction to water. We conducted the first experimental test of this hypothesis by providing bird seed, water, or bird seed and water at 2 national monuments in Arizona, USA, and followed the responses of adult western diamond-backed rattlesnakes (Crotalus atrox) equipped with radiotransmitters, and endothermic prey species, primarily rodents, birds, and lagomorphs. We found differing responses among prey taxa to supplemental food and water provisioning: rodents showed no response to any treatment, birds responded to food treatments, and lagomorphs responded to water treatments. Overall, spatial responses by adult rattlesnakes were weak, but several subjects appeared to respond to individual treatment grids. We did not find evidence of a direct response by rattlesnakes to supplemental water. Overall, we found little support for the prevalent belief that food and water sources at provisioning stations increase local concentrations of rattlesnakes; we provide several explanations for this counter-intuitive result. 2015 The Wildlife Society.
KEY WORDS Arizona, artificial waters, birds, Crotalus atrox, lagomorph, nuisance wildlife, small mammal, resource supplementation.
Mitigation translocation of nuisance animals is a commonly used management practice aimed at reso... more Mitigation translocation of nuisance animals is a commonly used management practice aimed at resolution of human-animal conflict by removal and release of an individual animal. Long considered a reasonable undertaking, especially by the general public, it is now known that translocated subjects are negatively affected by the practice. Mitigation translocation is typically undertaken with individual adult organisms and has a much lower success rate than the more widely practiced conservation translocation of threatened and endangered species. Nonetheless, the public and many conservation practitioners believe that because population-level conservation translocations have been successful that mitigation translocation can be satisfactorily applied to a wide variety of human-wildlife conflict situations. We reviewed mitigation translocations of reptiles, including our own work with 3 long-lived species (Gila monsters [Heloderma suspectum], Sonoran desert tortoises [Gopherus morafkai], and western diamond-backed rattlesnakes [Crotalus atrox]). Overall, mitigation translocation had a low success rate when judged either by effects on individuals (in all studies reviewed they exhibited increased movement or increased mortality) or by the success of the resolution of the human-animal conflict (translocated individuals often returned to the capture site). Careful planning and identification of knowledge gaps are critical to increasing success rates in mitigation translocations in the face of increasing pressure to find solutions for species threatened by diverse anthropogenic factors, including climate change and exurban and energy development.
abstract. We examined the relationship between insolation, climate, and hibernacula of black-tail... more abstract. We examined the relationship between insolation, climate, and hibernacula of black-tailed (Crotalus molossus), Great Basin (Crotalus lutosus), and western diamondback (Crotalus atrox) rattlesnakes at 4 sites in Arizona, Nevada, and Utah, Hibernacula were ...
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bird baths, may alter bird and mammal abundance, distribution, and recruitment; yet no studies have
examined the indirect effects of resource supplementation on terrestrial reptilian mesopredators such as
rattlesnakes. In the southwestern deserts of North America, anecdotal evidence suggests provisioning birds
with food and water attracts rattlesnakes to exurban yards, either indirectly by increasing prey availability or
directly through attraction to water. We conducted the first experimental test of this hypothesis by
providing bird seed, water, or bird seed and water at 2 national monuments in Arizona, USA, and followed
the responses of adult western diamond-backed rattlesnakes (Crotalus atrox) equipped with radiotransmitters,
and endothermic prey species, primarily rodents, birds, and lagomorphs. We found differing
responses among prey taxa to supplemental food and water provisioning: rodents showed no response to any
treatment, birds responded to food treatments, and lagomorphs responded to water treatments. Overall,
spatial responses by adult rattlesnakes were weak, but several subjects appeared to respond to individual
treatment grids. We did not find evidence of a direct response by rattlesnakes to supplemental water.
Overall, we found little support for the prevalent belief that food and water sources at provisioning stations
increase local concentrations of rattlesnakes; we provide several explanations for this counter-intuitive
result. 2015 The Wildlife Society.
KEY WORDS Arizona, artificial waters, birds, Crotalus atrox, lagomorph, nuisance wildlife, small mammal, resource
supplementation.
bird baths, may alter bird and mammal abundance, distribution, and recruitment; yet no studies have
examined the indirect effects of resource supplementation on terrestrial reptilian mesopredators such as
rattlesnakes. In the southwestern deserts of North America, anecdotal evidence suggests provisioning birds
with food and water attracts rattlesnakes to exurban yards, either indirectly by increasing prey availability or
directly through attraction to water. We conducted the first experimental test of this hypothesis by
providing bird seed, water, or bird seed and water at 2 national monuments in Arizona, USA, and followed
the responses of adult western diamond-backed rattlesnakes (Crotalus atrox) equipped with radiotransmitters,
and endothermic prey species, primarily rodents, birds, and lagomorphs. We found differing
responses among prey taxa to supplemental food and water provisioning: rodents showed no response to any
treatment, birds responded to food treatments, and lagomorphs responded to water treatments. Overall,
spatial responses by adult rattlesnakes were weak, but several subjects appeared to respond to individual
treatment grids. We did not find evidence of a direct response by rattlesnakes to supplemental water.
Overall, we found little support for the prevalent belief that food and water sources at provisioning stations
increase local concentrations of rattlesnakes; we provide several explanations for this counter-intuitive
result. 2015 The Wildlife Society.
KEY WORDS Arizona, artificial waters, birds, Crotalus atrox, lagomorph, nuisance wildlife, small mammal, resource
supplementation.