• An autonomous GPS geofence alert system to curtail avian fatalities at wind farms

      Sheppard, James; McGann, Andrew; Lanzone, Michael; Swaisgood, Ronald R. (2015)
      Wind energy developments are increasingly proliferating as nations seek to secure clean and renewable energy supplies. Wind farms have serious impacts on avifauna populations through injuries sustained by collisions with turbines. Our aim was to develop new biotelemetric technologies to minimize collision risks, particularly for threatened and endangered bird species whose ranges overlap with current and future wind farm sites.
    • Animal cytogenetics

      Houck, Marlys L.; Lear, Teri L.; Charter, Suellen J.; Arsham, Marilyn S.; Barch, Margaret J.; Lawce, Helen J. (John Wiley & Sons, Inc., 2017)
      Chromosome karyotyping and gene mapping has been carried out for a wide variety of animal species and continues to expand. Cross-species chromosome painting, or Zoo-FISH, for example, can now be used to identify genome segments originating from a common ancestor that have been conserved between species for millions of years....
    • California condor recovery: a work in progress

      Wallace, Michael P.; Lamont, Miles M. (Hancock House PublishersToronto, Ontario, Canada. Surrey, BC, Canada., 2014)
    • California condors and DDT: Examining the effects of endocrine disrupting chemicals in a critically endangered species

      Tubbs, Christopher W. (2016)
      In 1987, the last free-flying California condor (Gymnogyps californianus) was captured and brought into captivity, rendering the species extinct in the wild. At the time, only 27 condors remained. Today, the population numbers approximately 430 individuals and though condors continue their remarkable recovery, they still face numerous challenges. One challenge, specific to condors inhabiting coastal regions, is exposure to the endocrine disrupting chemical (EDC) p,p'-DDE, through the scavenging of marine mammal carcasses. The exposure levels these birds currently experience appears to be causing eggshell thinning, reminiscent of the phenomenon that nearly collapsed populations of several avian species decades ago. We were interested in further exploring the potential effects of EDCs on California condors. Investigating EDC effects on a critically endangered species like the condor can be difficult, with limited options for studies that can be feasibly conducted. Therefore, we conducted non-invasive, in vitro estrogen receptor (ESR) activation assays to characterize activation by EDCs that coastal condors encounter. Here, I give a brief history of EDCs effects on birds, and in particular the California condor. Additionally, our ESR data are summarized and mechanisms of eggshell thinning are reviewed, highlighting the potential implications of EDC exposure on the continued recovery of the California condor.
    • Foraging behavior, contaminant exposure risk, and the stress response in wild California condors (Gymnogyps californianus)

      Glucs, Zeka E.; Smith, Donald R.; Tubbs, Christopher W.; Bakker, Victoria J.; Wolstenholme, Rachel; Dudus, Kristina; Burnett, Joseph; Clark, Melissa; Clark, Michael; Finkelstein, Myra E. (2020)
      Wild California condors (Gymnogyps californianus) are frequently exposed to lead via lead-based ammunition ingestion, and recent studies indicate significant exposure to organochlorines (e.g. dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs)) for condors feeding on beach-cast marine mammals. We investigated the influence of contaminant exposure on condor glucocorticoid response through comparisons between wild and captive populations and identified modifiers of glucocorticoid release….
    • Glucocorticoid measurement in plasma, urates, and feathers from California condors (Gymnogyps californianus) in response to a human-induced stressor

      Glucs, Zeka E.; Smith, Donald R.; Tubbs, Christopher W.; Scherbinski, Jennie Jones; Welch, Alacia; Burnett, Joseph; Clark, Michael; Eng, Curtis; Finkelstein, Myra E. (2018)
      Vertebrates respond to stressful stimuli with the secretion of glucocorticoid (GC) hormones, such as corticosterone (CORT), and measurements of these hormones in wild species can provide insight into physiological responses to environmental and human-induced stressors. California condors (Gymnogyps californianus) are a critically endangered and intensively managed avian species for which information on GC response to stress is lacking. Here we evaluated a commercially available I125 double antibody radioimmunoassay (RIA) and an enzyme-linked immunosorbent assay (ELISA) kit for measurement of CORT and GC metabolites (GCM) in California condor plasma, urate, and feather samples. The precision and accuracy of the RIA assay outperformed the ELISA for CORT and GCM measurements, and CORT and GCM values were not comparable between the two assays for any sample type. RIA measurements of total CORT in condor plasma collected from 41 condors within 15 minutes of a handling stressor were highly variable (median = 70 ng/mL, range = 1–189 ng/mL) and significantly different between wild and captive condors (p = 0.02, two-tailed t-test, n = 10 wild and 11 captive). Urate GCM levels (median = 620 ng/g dry wt., range = 0.74–7200 ng/g dry wt., n = 216) significantly increased within 2 hr of the acute handling stressor (p = 0.032, n = 11 condors, one-tailed paired t-test), while feather section CORT concentrations (median = 18 pg/mm, range = 6.3–68 ng/g, n = 37) also varied widely within and between feathers. Comparison of multiple regression linear models shows condor age as a significant predictors of plasma CORT levels, while age, sex, and plasma CORT levels predicted GCM levels in urates collected within 30 min of the start of handling. Our findings highlight the need for validation when selecting an immunoassay for use with a new species, and suggest that non-invasively collected urates and feathers hold promise for assessing condor responses to acute or chronic environmental and human-induced stressors.
    • Health risks from lead-based ammunition in the environment

      Bellinger, David C.; Burger, Joanna; Cade, Tom J.; Cory-Slechta, Deborah A.; Finkelstein, Myra; Hu, Howard; Kosnett, Michael; Landrigan, Philip J.; Lanphear, Bruce; Pokras, Mark A.; et al. (2013)
      ...No rational deliberation about the use of lead-based ammunition can ignore the overwhelming evidence for the toxic effects of lead, or that the discharge of lead bullets and shot into the environment poses significant risks of lead exposure to humans and wildlife. Given the availability of non-lead ammunition for shooting and hunting (Thomas 2013), the use of lead-based ammunition that introduces lead into the environment can be reduced and eventually eliminated. This seems to be a reasonable and equitable action to protect the health of humans and wildlife....
    • Hierarchical dominance structure in reintroduced California condors: correlates, consequences, and dynamics

      Sheppard, James; Walenski, Matthew; Wallace, Michael P.; Vargas Velazco, J.J.; Porras, C.; Swaisgood, Ronald R. (2013)
      Populations of reintroduced California condors (Gymnogyps californianus) develop complex social structures and dynamics to maintain stable group cohesion, and birds that do not successfully integrate into group hierarchies have highly impaired survivability. Consequently, improved understanding of condor socioecology is needed to inform conservation management strategies…
    • Identification of California condor (Gymnogyps californianus) estrogen receptor variants and their activation by xenoestrogens

      Felton, Rachel G.; Owen, Corie M.; Cossaboon, Jennifer M.; Steiner, Cynthia C.; Tubbs, Christopher W. (2020)
      California condors released in costal sites are exposed to high levels of xenoestrogens, particularly p,p'-DDE, through scavenging of marine mammal carcasses. As a result, coastal condors carry a higher contaminant loads and experience eggshell thinning when compared to their inland counterparts....
    • Identification of California condor estrogen receptors 1 and 2 and their activation by endocrine disrupting chemicals

      Felton, Rachel G.; Steiner, Cynthia C.; Durrant, Barbara S.; Keisler, Duane H.; Milnes, Matthew R.; Tubbs, Christopher W. (2015)
      ...There is evidence that coastal-dwelling condors experience reproductive issues, such as eggshell thinning, likely resulting from exposure to endocrine-disrupting chemicals (EDCs). To address this problem, we have identified and cloned condor estrogen receptors (ESRs) 1 and 2 and characterized their activation by EDCs present in the coastal habitats where condors reside....
    • Lead exposure risk from trash ingestion by the endangered California condor (Gymnogyps californianus)

      Finkelstein, Myra E.; Brandt, Joseph; Sandhaus, Estelle; Grantham, Jesse; Mee, Allan; Schuppert, Patricia Jill; Smith, Donald R. (2015)
      Lead poisoning from ingestion of spent lead ammunition is one of the greatest threats to the recovery of California Condors (Gymnogyps californianus) in the wild…. Our results suggest that trash ingestion of nonammunition items does not pose a significant lead exposure risk to the California Condor population in California.
    • Lead in ammunition: A persistent threat to health and conservation

      Johnson, C. K.; Kelly, T. R.; Rideout, Bruce (2013)
      Many scavenging bird populations have experienced abrupt declines across the globe, and intensive recovery activities have been necessary to sustain several species, including the critically endangered California condor (Gymnogyps californianus). Exposure to lead from lead-based ammunition is widespread in condors and lead toxicosis presents an immediate threat to condor recovery, accounting for the highest proportion of adult mortality….
    • Movement-based estimation and visualization of space use in 3D for wildlife ecology and conservation

      Tracey, Jeff A.; Sheppard, James; Zhu, Jun; Wei, Fuwen; Swaisgood, Ronald R.; Fisher, Robert N.; Sueur, Cédric; Sueur, Cédric (2014)
      Advances in digital biotelemetry technologies are enabling the collection of bigger and more accurate data on the movements of free-ranging wildlife in space and time. Although many biotelemetry devices record 3D location data with x, y, and z coordinates from tracked animals, the third z coordinate is typically not integrated into studies of animal spatial use. Disregarding the vertical component may seriously limit understanding of animal habitat use and niche separation. We present novel movement-based kernel density estimators and computer visualization tools for generating and exploring 3D home ranges based on location data. We use case studies of three wildlife species – giant panda, dugong, and California condor – to demonstrate the ecological insights and conservation management benefits provided by 3D home range estimation and visualization for terrestrial, aquatic, and avian wildlife research.
    • Seroepidemiologic survey of potential pathogens in obligate and facultative scavenging avian species in California

      Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K. (2015)
      Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats.
    • Two decades of cumulative impacts to survivorship of endangered California condors in California

      Kelly, Terra R.; Rideout, Bruce; Grantham, Jesse; Brandt, Joseph; Burnett, L. Joseph; Sorenson, Kelly J.; George, Daniel; Welch, Alacia; Moen, David; Rasico, James; et al. (2015)
      …Lead poisoning, which was a major driver in the population's decline, was a leading cause of death accounting for the greatest adult mortality, and lead exposure remains the most significant threat. Recent lead ammunition reduction efforts in the condor range in California hold promise for improving the recovery potential for this population.