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Brian Halstead

Dr. Brian Halstead is a Research Wildlife Biologist with the Western Ecological Research Center.

He focuses on conservation of reptiles and amphibians, particularly applications of population ecology to species conservation. In particular, he combines field methods like capture-mark-recapture and radio telemetry with flexible Bayesian hierarchical models to learn about demographic parameters and the individual, biotic, and environmental variables that affect them. Central themes of his research include the influence of land use, climate, and biotic interactions on species distributions and demographic rates; the behavioral response of individuals to habitat change; and providing relevant information for wildlife conservation to resource managers and private landowners. Currently, Dr. Halstead's research focuses on the effects of water availability on the distribution, behavior, and demography of giant gartersnakes (Thamnophis gigas); the response of San Francisco gartersnakes (Thamnophis sirtalis tetrataenia) to grazing and management of aquatic invasive species; and the influence of abiotic and biotic variables on the distribution and demography of amphibian populations in northern California. Additional research projects include the distribution, growth, and demography of island night lizards (Xantusia riversiana) on San Nicolas Island and monitoring Townsend’s big-eared bat (Corynorhinus townsendii) maternal colonies at Point Reyes National Seashore.

RESEARCH INTERESTS

  • Population Ecology
  • Conservation Biology
  • Herpetology
  • Bayesian Statistics

Education and Certifications

  • B.S. in Biology, Carroll College (Waukesha, WI), 1999

  • Ph.D. in Biology, University of South Florida, 2008

Science and Products

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Aerial view of five gulls, with grey backs and wings and white heads and tails, flying over the ocean

Birds, Bats, and Beyond: Networked Wildlife Tracking in the Southern California Bight

Seabird and bat researchers from the USGS Western Ecological Research Center are teaming up to study how flying animals move through the marine environment. This Bureau of Ocean Energy Management supported project will add 25 remote telemetry stations to the existing global Motus Wildlife Tracking System, representing the largest single investment in coastal and offshore Motus infrastructure on...
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Species Management Research Program, Western Ecological Research Center (WERC)
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Birds, Bats, and Beyond: Networked Wildlife Tracking in the Southern California Bight

Seabird and bat researchers from the USGS Western Ecological Research Center are teaming up to study how flying animals move through the marine environment. This Bureau of Ocean Energy Management supported project will add 25 remote telemetry stations to the existing global Motus Wildlife Tracking System, representing the largest single investment in coastal and offshore Motus infrastructure on...
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Bats benefit from maintaining a close-knit roosting group.

Tracking Bats and Coronaviruses

Below are the USGS 2020 Coronavirus Aid, Relief and Economic Security Act (CARES Act) research projects related to tracking bats and coronaviruses. Select tabs above for related items.
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Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Fort Collins Science Center, National Wildlife Health Center, Western Ecological Research Center (WERC)
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Tracking Bats and Coronaviruses

Below are the USGS 2020 Coronavirus Aid, Relief and Economic Security Act (CARES Act) research projects related to tracking bats and coronaviruses. Select tabs above for related items.
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SFGS

Ecology and Conservation of Reptiles

This project improves our understanding of the ecology of reptiles in California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of reptiles to understand factors that affect where they are found and how populations change. He further explores the relationships of reptiles with their abiotic and...
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Ecosystems Mission Area, Species Management Research Program, Western Ecological Research Center (WERC)
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Ecology and Conservation of Reptiles

This project improves our understanding of the ecology of reptiles in California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of reptiles to understand factors that affect where they are found and how populations change. He further explores the relationships of reptiles with their abiotic and...
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Image: California Red-legged Frog

Ecology and Conservation of Amphibians in Northern California

This project improves our understanding of the ecology of amphibians in northern California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of amphibians to understand factors that affect where amphibians are found and how populations change. He further explores the relationships of amphibians with...
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Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Species Management Research Program, Western Ecological Research Center (WERC)
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Ecology and Conservation of Amphibians in Northern California

This project improves our understanding of the ecology of amphibians in northern California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of amphibians to understand factors that affect where amphibians are found and how populations change. He further explores the relationships of amphibians with...
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hoary bat

Bat Research in California

The primary goal of this bat research program is to develop projects that increase our understanding of basic ecology and natural history of western bat species, while simultaneously providing needed data to inform conservation measures and management decisions in the West. Dr. Brian Halstead, together with Gabriel Reyes, studies the habitat and resource selection, movement ecology, demography...
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Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Species Management Research Program, Western Ecological Research Center (WERC)
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Bat Research in California

The primary goal of this bat research program is to develop projects that increase our understanding of basic ecology and natural history of western bat species, while simultaneously providing needed data to inform conservation measures and management decisions in the West. Dr. Brian Halstead, together with Gabriel Reyes, studies the habitat and resource selection, movement ecology, demography...
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Photo of waterbirds feeding at a flooded agricultural field.

Dixon Field Station

WERC scientists at the Dixon Field Station conduct studies from the San Francisco Bay-Delta in California to the Great Basin spanning California and Nevada.
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Western Ecological Research Center (WERC)
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Dixon Field Station

WERC scientists at the Dixon Field Station conduct studies from the San Francisco Bay-Delta in California to the Great Basin spanning California and Nevada.
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Filter Total Items: 32

Mercury concentrations in amphibian tissues across the United States, 2016-2021

Comma-separated values (.csv) file containing data related to amphibian sampling across the United States between 2016 and 2021. Data files contain mercury concentrations in amphibian and dragonfly tissues, mercury concentrations in sediment, as well as amphibian morphometrics, and habitat and climate characteristics where the samples were collected.
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Forest and Rangeland Ecosystem Science Center

San Francisco Gartersnake Fecundity Data from San Mateo County, California Collected from 2019-2022

Adult female San Francisco gartersnakes (Thamnophis sirtalis tetrataenia) were captured and examined using an ultrasound device to determine if they were gravid and count the number of embryos in those that were. Morphological data including length and mass were collected for each snake, along with the date of capture and a study site identifier. These data support the following publication: Scho
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Western Ecological Research Center (WERC)

Demographic Parameter Estimates for San Francisco Gartersnakes (Thamnophis sirtalis tetrataenia) for Fitting an Integral Projection Model

A study comparing reintroduction scenarios for the San Francisco gartersnake (Thamnophis sirtalis tetrataenia), an endangered subspecies native to San Mateo County and Santa Cruz County in northern California. Models for snake survival, growth, fecundity, and reproductive status were used to construct a demographic population model. Data are posterior distributions for demographic parameters from
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Western Ecological Research Center (WERC)

Egg Mass Counts from Foothill Yellow-Legged Frogs (Rana boylii) in California from 1992-2021

We compiled time series of egg mass counts (an index of adult female abundance) from Rana boylii populations in 36 focal streams and fit a Multiple Population Viability Analysis (MPVA) model to quantify how streamflow metrics, stream temperature, and surrounding land cover affect population growth. In addition, data on streamflow, stream temperature, and surrounding land cover for each stream were
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Western Ecological Research Center (WERC)

Survey Results for Temblor Legless Lizards (Anniella alexanderae) in the San Joaquin Valley of California, 2022 and 2023

Locations of sites at which U.S. Geological Survey (USGS) biologists surveyed for Temblor legless lizards (Anniella alexanderae) in 2022 and 2023 and the results of those surveys. At the time of the species description, little was known about the distribution of the Temblor legless lizard beyond a few localities. Surveys were designed to gather information on the distribution of Temblor legless li
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Western Ecological Research Center (WERC)

Western Pond Turtle (Emys [Actinemys] marmorata) Observations at Point Reyes National Seashore and Golden Gate National Recreation Area

These data represent incidental observations of western pond turtles (Emys [Actinemys] marmorata) collected by the U.S. Geological Survey, Western Ecological Research Center, at Point Reyes National Seashore and Golden Gate National Recreation Area between 1993 and 2014. These data do not have associated survey effort, and are intended to represent incidental observations, rather than a random, sy
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Western Ecological Research Center (WERC)

Survival Data for Translocated Adults and Captive-Reared Juvenile Giant Gartersnakes in Sacramento County, California (2018-2021)

The dataset consists of two csv files one for adult snakes and one for captive-reared juvenile snakes. The data contains start times (when snakes entered the study) and end times (when snakes died or were censored from the study) for survival analysis. The data also contains general information about the individual snakes (id, snout-vent length, treatment group, whether or not they were translocat
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Western Ecological Research Center (WERC)

Multi-State Occurrence Data and Predictors for Amphibians in Yosemite National Park (2007-2021)

These data include field-collected observations of the occurrence of adult and larval amphibians at 174 sites in 14 watersheds at Yosemite National Park from 2007 through 2021. Also included in the data are potential variables affecting site occurrence, probability of reproduction, and probability of detection of amphibians, including static site-specific variables like site size and elevation, an
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Western Ecological Research Center (WERC)

Data to Fit an Occupancy Model to Trapping Data for the Northwestern Pond Turtle and Red-Eared Slider in the Sacramento Valley (2018) and Sacramento-San Joaquin River Delta (2019)

These data represent the results of trapping efforts for native northwestern pond turtles (Actinemys marmorata) and non-native red-eared sliders (Trachemys scripta elegans) in wetlands and irrigation canals in agricultural regions of the Sacramento Valley in 2018 and the Sacramento-San Joaquin River Delta in 2019. In addition to detection data for these two turtle species, the dataset includes hab
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Western Ecological Research Center (WERC)

USGS Occupancy Surveys for Dixie Valley Toads, Anaxyrus williamsi, in Churchill County, Nevada from April 2018 to May 2021

Desert spring wetlands host many endemic species that require aquatic habitat and are isolated by the surrounding xeric terrestrial habitat. The Dixie Valley Toad (Anaxyrus williamsi) is a recently described anuran species endemic to desert spring wetlands in the Dixie Valley, Churchill County, Nevada, USA. Given this species was only recently recognized as distinct from Anaxyrus boreas, little is
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Western Ecological Research Center (WERC)

Temperature and Relative Conductivity at Sampling Locations in the Dixie Valley, Churchill County, Nevada, 2019-2021

These data provide temperatures and relative conductivity to determine the presence or absence of water at specific locations in Dixie Meadows, Dixie Valley, Churchill County, Nevada, 2019-2021.
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Western Ecological Research Center (WERC)

Time to First Detection of Northwestern Pond Turtles and Red-eared Sliders by Bait Type in the Sacramento Valley, California, 2018

These data provide the time to first detection in days of Northwestern Pond Turtles (Actinemys marmorata) and Red-eared Sliders (Trachemys scripta elegans) by trapping location and bait type in the Sacramento Valley, California, in 2018. Bait types evaluated include sardines and dry cat food. Only location, species, and bait type combinations that resulted in captures are included. These data a
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Western Ecological Research Center (WERC)
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Filter Total Items: 87

Priority research needs to inform amphibian conservation in the Anthropocene

The problem of global amphibian declines has prompted extensive research over the last three decades. Initially, the focus was on identifying and characterizing the extent of the problem, but more recently efforts have shifted to evidence-based research designed to identify best solutions and to improve conservation outcomes. Despite extensive accumulation of knowledge on amphibian declines, there
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Evan H. Campbell Grant, Staci M. Amburgey, Brian Gratwicke, Victor Acosta Chaves, Anat M. Belasen, David Bickford, Carsten Brühl, Natalie E. Calatayud, Nick Clemann, Simon Clulow, Jelka Crnobrnja-Isailovic, Jeff Dawson, David A. De Angelis, C. Kenneth Dodd, Annette Evans, Gentile Francesco Ficetola, Mattia Falaschi, Sergio González-Mollinedo, David M. Green, Roseanna Gamlen-Greene, Richard A. Griffiths, Brian J. Halstead, Craig Hassapakis, Geoffrey Heard, Catharina Karlsson, Tom Kirschey, Blake Klocke, Tiffany A. Kosch, Sophia Kusterko Novaes, Luke Linhoff, John C. Maerz, Brittany A. Mosher, Katherine M O'Donnell, Leticia M. Ochoa-Ochoa, Deanna H. Olson, Kristiina Ovaska, J. Dale Roberts, Aimee J. Silla, Tariq Stark, Jeanne Tarrant, R. Upton, Judit Vörös, Erin L. Muths
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Ecosystems Mission Area, Species Management Research Program, Eastern Ecological Science Center, Fort Collins Science Center, Western Ecological Research Center (WERC)

Identifying drivers of population dynamics for a stream breeding amphibian using time series of egg mass counts

The decline in amphibian populations is one of the starkest examples of the biodiversity crisis. For stream breeding amphibians, alterations to natural flow regimes by dams, water diversions, and climate change have been implicated in declines and extirpations. Identifying drivers of amphibian declines requires long time series of abundance data because amphibian populations can exhibit high natur
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Jonathan P. Rose, Sarah J. Kupferberg, Ryan A. Peek, Don Ashton, James B. Bettaso, Steven Bobzien, Ryan M. Bourque, Koen G.H. Breedveld, Alessandro Catenazzi, Joseph E. Drennan, Earl Gonsolin, Marcia Grefsrud, Andrea E. Herman, Matthew R. House, Matt R. Kluber, Amy J. Lind, Karla R. Marlow, Alan Striegle, Michael van Hattem, Clara A. Wheeler, Jeffery T. Wilcox, Kevin D. Wiseman, Brian J. Halstead
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Ecosystems Mission Area, Western Ecological Research Center (WERC)

Keeping the heat on: Weighted surveillance for Chytrid fungus (Batrachochytirum dendrobatidis) in Dixie Valley toads (Anaxyrus [= Bufo] williamsi)

Introduced fungal pathogens have caused declines and extinctions of naïve wildlife populations across vertebrate classes. Consequences of introduced pathogens to hosts with small ranges might be especially severe because of limited redundancy to rescue populations and lower abundance that may limit the resilience of populations to perturbations like disease introduction. As a complement to biosecu
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Matthew J. Forrest, Brian J. Halstead, Daniel A. Grear, Patrick M. Kleeman, Brian D. Todd, Oliver J. Miano, Kris D. Urquhart
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Ecosystems Mission Area, National Wildlife Health Center, Western Ecological Research Center (WERC)

Survival and establishment of captive-reared and translocated giant gartersnakes after release

Many imperiled species face increasing extinction risk that requires interventional management like translocation or captive rearing. The use of translocations to successfully restore or create populations requires that animals survive at recipient sites, information that is often lacking for imperiled species and that can be risky to acquire if not obtained before a species has dwindled in number
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Allison M. Nguyen, Brian D Todd, Brian J. Halstead
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Ecosystems Mission Area, Western Ecological Research Center (WERC)

Sierra Nevada amphibians demonstrate stable occupancy despite precipitation volatility in the early 21st Century

Climate can have a strong influence on species distributions, and amphibians with different life histories might be affected by annual variability in precipitation in different ways. The Sierra Nevada of California, United States, experienced some of the driest and wettest years on record in the early 21st Century, with variability in annual precipitation predicted to increase with climate change.
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Brian J. Halstead, Patrick M. Kleeman, Jonathan P. Rose, Gary M. Fellers
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Ecosystems Mission Area, Western Ecological Research Center (WERC)

Are canned sardines or dry cat food more effective as bait for capturing Northwestern Pond Turtles (Actinemys marmorata) and Red-eared Sliders (Trachemys scripta elegans)?

During an occupancy study of Northwestern Pond Turtles (Actinemys marmorata) and Red-eared Sliders (Trachemys scripta elegans) in California’s Sacramento Valley in 2018, we tested the relative effectiveness of 2 bait types: sardines packed in soybean oil and Meow Mix® Original Choice dry cat food. We sampled 116 sites with 2 traps each: one baited with sardines and one baited with dry cat food. Sa
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Alexandria M Fulton, Jonathan P. Rose, Brian J. Halstead
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Ecosystems Mission Area, Western Ecological Research Center (WERC)

Hot, wet and rare: Modelling the occupancy dynamics of the narrowly distributed Dixie Valley toad

Context: Small population sizes and no possibility of metapopulation rescue put narrowly distributed endemic species under elevated risk of extinction from anthropogenic change. Desert spring wetlands host many endemic species that require aquatic habitat and are isolated by the surrounding xeric terrestrial habitat.Aims: We sought to model the occupancy dynamics of the Dixie Valley toad (Anaxyrus
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Jonathan P. Rose, Patrick M. Kleeman, Brian J. Halstead
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Ecosystems Mission Area, Western Ecological Research Center (WERC)

Optimizing survey design for shasta salamanders (Hydromantes spp.) to estimate occurrence in little-studied portions of their range

Shasta salamanders (collectively, Hydromantes samweli, H. shastae, and H. wintu; hereafter, Shasta salamander) are endemic to northern California in the general vicinity of Shasta Lake reservoir. Although generally associated with limestone, they have repeatedly been found in association with other habitats, calling into question the distribution of the species complex. Further limiting our knowle
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Brian J. Halstead, Patrick M. Kleeman, Graziella Vittoria Direnzo, Jonathan P. Rose
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Ecosystems Mission Area, Eastern Ecological Science Center, Western Ecological Research Center (WERC)

Riparian buffers provide refugia during secondary forest succession

AimSecondary forests regenerating from human disturbance are increasingly becoming a predominant forest type in many regions, and they play a significant role in forest community dynamics. Understanding the factors that underlie the variation in species responses during secondary succession is important for understanding community assembly and biodiversity monitoring and management. Because specie
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Michelle E. Thompson, Brian J. Halstead, Maureen A. Donnelly
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Ecosystems Mission Area, Western Ecological Research Center (WERC)

Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians
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Beth A. Reinke, Hugo Cayuela, Fredric J. Janzen, Jean-François Lemaitre, Jean-Michel Gaillard, A. Michelle Lawing, John B. Iverson, Ditte G Christiansen, Iñigo Martínez-Solano, Gregorio Sánchez-Montes, Jorge Gutiérrez-Rodríguez, Francis L Rose, Nicola J. Nelson, Susan Keall, Alain J Crivelli, Theodoros Nazirides, Annegret Grimm-Seyfarth, Klaus Henle, Emiliano Mori, Gaëtan Guiller, Rebecca Homan, Anthony Olivier, Erin L. Muths, Blake R. Hossack, Xavier Bonnet, David Pilliod, Marieke Lettink, Tony Whitaker, Benedikt R. Schmidt, Michael G. Gardner, Marc Cheylan, Françoise Poitevin, Ana Golubović, Ljiljana Tomović, Dragan Arsovski, Richard A Griffiths, Jan W. Arntzen, Jean-Pierre Baron, Jean-François Le Galliard, Thomas Tully, Luca Luiselli, Massimo Capula, Lorenzo Rugiero, Rebecca McCaffery, Lisa A Eby, Briggs-Gonzalez; Venetia, Frank Mazzotti, David M. Pearson, Brad A. Lambert, David M. Green, Nathalie Jreidini, Claudio Angelini, Graham Pyke, Jean-Marc Thirion, Pierre Joly, Jean-Paul Léna, Tony Tucker, Col Limpus, Pauline Priol, Aurélien Besnard, Pauline Bernard, Kristin Stanford, Richard S. King, Justin M Garwood, Jaime Bosch, Franco Souza, Jaime Bertoluci, Shirley Famelli, Kurt Grossenbacher, Omar Lenzi, Kathleen Matthews, Sylvain Boitaud, Deanna H. Olson, Tim Jessop, Graeme Gillspie, Jean Clobert, Murielle Richard, Andrés Valenzuela-Sánchez, Gary M. Fellers, Patrick M. Kleeman, Brian J. Halstead, Evan H. Campbell Grant, Phillip G Byrne, Thierry Frétey, Gernard Le Garff, Pauline Levionnois, John C. Maerz, Julian Pichenot, Kurtulus Olgun, Nazan Üzüm, Aziz Avcı, Claude Miaud, Johan Elmberg, Gregory P Brown, Richard Shine, Nathan F Bendik, Lisa O'Donnell, Courtney L. Davis, Michael J Lannoo, Rochelle M Stiles, Robert M Cox, Aaron M Reedy, Daniel A. Warner, Eric Bonnaire, Kristine Grayson, Roberto Ramos-Targarona, Eyup Baskale, David J. Muñoz, John Measey, F. Andre de Villiers, Will Selman, Victor Ronget, Anne M. Bronikowski, David A W Miller
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Ecosystems Mission Area, Fort Collins Science Center, Western Ecological Research Center (WERC)

Integrating growth and survival models for flexible estimation of size-dependent survival in a cryptic, endangered snake

Estimates of demographic rates for animal populations and individuals have many applications for ecological and conservation research. In many animals, survival is size-dependent, but estimating the form of the size–survival relationship presents challenges. For elusive species with low recapture rates, individuals’ size will be unknown at many points in time. Integrating growth and capture–mark–r
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Jonathan P. Rose, Richard Kim, Elliot James Schoenig, Patrick C. Lien, Brian J. Halstead
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Ecosystems Mission Area, Western Ecological Research Center (WERC)

Looking ahead, guided by the past: The role of U.S. national parks in amphibian research and conservation

Protected areas like national parks are essential elements of conservation because they limit human influence on the landscape, which protects biodiversity and ecosystem function. The role of national parks in conservation, however, often goes far beyond limiting human influence. The U.S. National Park Service and its system of land units contribute substantively to conservation by providing prote
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Brian J. Halstead, Andrew M. Ray, Erin L. Muths, Evan H. Campbell Grant, Rob Grasso, Michael J. Adams, Kathleen Semple Delaney, Jane Carlson, Blake R. Hossack
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Ecosystems Mission Area, Western Ecological Research Center (WERC)

Code to fit Integral Projection Models and simulate population reintroductions for San Francisco Gartersnakes, Thamnophis sirtalis tetrataenia

This repository contains code to fit Integral Projection Models and simulate population reintroductions for San Francisco gartersnakes (Thamnophis sirtalis tetrataenia) This repository specifically contains code to reproduce analyses in: Rose, J.P., Kim, R., Schoenig, E.J., Lien, P.C., and Halstead, B.J. in-review. Comparing reintroduction strategies for the endangered San Francisco gartersnake (
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Western Ecological Research Center (WERC)

Code for Multiple Population Viability Analysis of egg mass time series from the Foothill Yellow-legged Frogs (Rana boylii) in California

Code to fit a Multiple Population Viability Analysis (MPVA) to time series of Foothill yellow-legged frog (Rana boylii) egg mass counts. Rose, J.P., and Halstead, B.J., 2023, Code for Multiple Population Viability Analysis of egg mass time series from the Foothill Yellow-legged Frogs (Rana boylii) in California: U.S. Geological Survey software release, https://doi.org/10.5066/P9QWX2GR. This code
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Western Ecological Research Center (WERC)

Code to analyze multi-state, multi-scale dynamic occupancy models for amphibians in Yosemite National Park

The purpose of this study was to evaluate how extreme variation in precipitation in the Sierra Nevada of California, USA, in the early 21st Century affected adult occupancy and the probability of reproduction of amphibians. The study used a 15-year data set to relate site characteristics to initial probability of occurrence of adults, and additional site-specific and dynamic (e.g., weather) variab
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Western Ecological Research Center (WERC)

Code to analyze survival data for Giant gatersnakes, Thamnophis gigas in Sacramento County, California from 2018 to 2021

The purpose of this study was to estimate the survival of giant gartersnakes (Thamnophis gigas) prior to and following translocation, as well as to evaluate the use of captive rearing as a conservation tool for giant gartersnakes. We used Kaplan-Meier and Cox Proportional Hazards models to estimate survival rates and estimate the effects of group identity (marsh donor, rice donor, and translocatio
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Western Ecological Research Center (WERC)

Code to Analyze Occupancy Data for Dixie Valley Toads, Anaxyrus williamsi in Churchill County, Nevada from 2018 to 2021

-R code to create and fit dynamic occupancy models to Dixie Valley Toad survey data in JAGS and produce useful summaries of model results. This script will perform the Gibbs Variable Selection (GVS) using the initial set of environmental covariates, and then fit the "final" model using only important environmental covariates. The dynamic occupancy model is adapted from the model published by Duart
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Western Ecological Research Center (WERC)

Code to analyze Capture-Mark-Recapture data of San Francisco gartersnakes (Thamnophis sirtalis tetrataenia)

Code files "growth_analysis.R" -An R script to fit the von Bertalanffy growth model to growth data from San Francisco gartersnakes. The von Bertalanffy growth model is fit using JAGS software (Plummer 2003), and is based on the model presented in Armstrong and Brooks (2013). "survival_analysis.R" -An R script to fit the robust-design Cormack-Jolly-Seber model to capture-mark-recapture data from
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Western Ecological Research Center (WERC)
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WERC Scientists Find that Threatened Snakes Depend on Agriculture (TWS Wildlife News)

SACRAMENTO – A new study shows how giant gartersnakes use Central Valley rice fields

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A Unified Research Strategy for Disease Management

As wildlife diseases increase globally, an understanding of host-pathogen relationships can elucidate avenues for management and improve conservation...

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Incoming! Learn about Bats with the USGS WERC

Around Halloween, USGS celebrates bats and other "spooky" creatures by sharing some of its research on these fascinating creatures! Check out social...

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