UPDATE: Restoring habitat for the endangered Amargosa vole (Pt. 1)

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Habitat where voles are trapped.   Voles almost exclusively utilize bulrush habitat in the Mojave Desert. Photo credit: Austin Roy (CDFW)

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Staff from WIL processing an Amargosa vole. Animals are handled for less than 5 min before being released where they were captured. Photo credit: Austin Roy (CDFW)

WIL just completed its one-year followup to last year’s emergency efforts to rescue Marsh 1, one of the largest and most important habitat patches for the endangered Amargosa vole. That effort included raising water in the marsh, clearing out debris, and translocating voles into nearby marshes during the restoration. In February 2017, researchers from CDFW-WIL and UC Davis with the help of the Amargosa Conservancy trapped the release marshes and conducted sign surveys to determine if voles were still present. They collected fecal and tissue samples from voles for genetic testing to detect if translocated voles might have reproduced in their new homes. Additionally, the team successfully trapped five new voles and one recapture in Marsh 1, indicating that voles survived the habitat restoration activities and potentially may have immigrated from nearby marshes.  As Marsh 1 habitat quality improves and the size of the marsh expands, our hope is that the vole population in the marsh will also grow.

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An Amargosa vole captured during field work. Photo credit: Austin Roy (CDFW)

The successful progress of this project highlights how productive partnerships between agencies, universities, and communities can positively benefit the conservation of endangered species.

The translocations and restoration were funded by the BLM (NCLS funds also), and Drought Response Implementation Program funds (DRIP) from CDFW.

New publication describes a mange outbreak in the endangered San Joaquin kit fox

The Wildlife Investigations Lab’s Deana Clifford and Jaime Rudd recently co-authored a publication with Brian Cypher from the Endangered Species Recovery Program (ESRP) describing a sarcoptic mange outbreak in endangered San Joaquin kit foxes inhabiting Bakersfield. These small foxes are only found in central California. Prior to the emergence of mange, foxes living in the city of Bakersfield were one of the most stable subpopulations of this endangered species.

A committed team of collaborators that includes ESRP, the California Living Museum (CALM Zoo), UC Davis, the California Animal Health and Food Safety Lab System (CAHFS, Davis), the California Department of Fish and Wildlife, and the U.S. Fish and Wildlife Service are continuing research and intervention efforts to minimize the conservation impact of mange on this endangered species.

To access the paper abstract, click here.

Full publication reference: Cypher, B.L., Rudd, J.L., Westall, T.L., Woods, L.W., Stephenson, N., Foley, J.E., Richardson, D. and Clifford, D.L. (2017). Sarcoptic Mange in Endangered Kit Foxes (Vulpes macrotis mutica): Case Histories, Diagnoses, and Implications for Conservation. Journal of Wildlife Diseases53(1); 46-53.

More information about our current research can be found following the link::

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The signs of sarcoptic mange in wild kit foxes can be missed in the early stages. However, as the disease progresses and the mites proliferate, the devastating toll this disease has on an individual is easily apparent. Pictured is a mangy kit fox in the later stages infestation showing hair loss, thickened crusty skin, and emaciation (A). Kit foxes with severe mange cannot hunt and often succumb to starvation and hypothermia. The CALM zoo in Bakersfield is a licensed wildlife rehabilitator and has been providing the treatment and veterinary care needed to return affected foxes to good health (Photo B).

WRMD-S (Wildlife Rehabilitation Medical Database-Surveillance): A novel wildlife disease surveillance tool for improving our understanding of wildlife health threats in California

 

Wildlife health is a key part of why the Wildlife Investigations Lab was formed and a vital part of the California Wildlife Action Plan. Disease and human impacts, such as land use change, invasive species and climate change, are significant drivers of wildlife health.  The impact on wildlife from these threats is rapidly increasing the need for an enhanced understanding of the major hazards to the health and survival of wild species, especially those that are difficult to monitor. In addition, given the increasing realization that wildlife diseases have a significant impact on human and domestic animal health, more efficient approaches for detection and monitoring of wildlife disease are necessary.

Developers at the Wild Neighbors Data Base, in collaboration with investigators at the Karen C. Drayer Wildlife Health Center (WHC) at the University of California Davis and the Wildlife Investigations Laboratory (WIL) at California Department of Fish and Wildlife (CDFW), designed and developed a web application that works in parallel with the free online Wildlife Rehabilitation Medical Database (WRMD) pronounced “wormed”.

The primary objective is to augment the on-line medical database (WRMD), with mechanisms to integrate and aggregate data from wildlife rehabilitation centers and detect and signal investigators to potential wildlife health events, and facilitate information sharing among wildlife rehabilitation centers and between centers and the CDFW and the WHC.

This project is the first of its kind and uses the valuable information collected by wildlife rehabilitation centers to enhance wildlife disease surveillance for many different species of birds, mammals, reptiles and amphibians across the state. In California, every year, between 65,000- 80,000 wild animals are found sick, injured or orphaned by the public and are taken to wildlife rehabilitation centers. Because of this, the wildlife rehabilitation centers in California are on the front line against wildlife disease and mortality events.

The project incorporates both disease specific and non-disease specific data in order to detect events that may warrant further investigation and diagnosis by WIL. The data is aggregated by species and then sorted against programmed thresholds, generated from four years of wildlife rehabilitation center admission data obtained from CDFW wildlife rehabilitation annual reports.  Species with numbers of admissions exceeding the thresholds, signifying a potential wildlife health event, are displayed as alerts.

The detailed view for each species exceeding the threshold includes a chart showing one or more years of data allowing for visualizations of trends over time (Fig.1).  By using Google Maps API the application includes a feature in which the location found for each case is displayed on the map (Fig.2).

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Figure 1. Chart displaying number of individuals admitted weekly over one year (top) and over 15 year period (bottom). This feature can be used to visualize long-term trends of admissions of each species.

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Figure 2. Map displaying the spatial distribution of cases in an alert and underlying data for a selected case.

Alerts are assessed each week and also evaluated for clusters of syndromes and specific diseases. Depending on the circumstances of the alerts, investigators at CDFW and the Wildlife Health Center conduct health investigations in collaboration with rehabilitation centers.  Data is collected on the outcome of the investigations, including any post-mortem examination findings and results of the diagnostic tests.  Data is also collected on the numbers of admissions for threatened and endangered species and animals on the species of special concerns list for California. Since launching the program in July, the numbers of alerts per week ranged from 11-58 (median = 48).  Alerts included clusters of specific diseases (lead poisoning, trichomonas) and/or syndromes (neurologic disease, hemorrhagic disease) as well as animals affected by oil and suspect poisoning cases. On average, four alerts were followed up on by investigators each week to request samples and/or in collaboration with the rehabilitation centers.

Recently, the application has alerted investigators to an adverse health event in Western and Clark’s Grebes and Double-crested cormorants. Several grebes and cormorants are presenting to centers in central and southern California with emaciation. CDFW is working with centers and field biologists to conduct post-mortem examinations and laboratory analyses to investigate the cause(s). These alerts mirror findings by scientists documenting a downward trend in these populations along the Pacific Coast, which is hypothesized to be due in part to a change in the abundance and availability of their food base.

This pilot project began on July 1, 2016 and will continue through 2018. Around 30 wildlife rehabilitation centers around the state are participating in the pilot project.

Prepared by Nicole Carion and Terra Kelly, DVM, PhD, Dipl. ACZM

CDFW and NPS team up to get word out about poisoned fox near Point Reyes National Seashore

Last September, a gray fox was found dead at a residence in Inverness in Marin County with no signs of trauma.  Since the residence was adjacent to the Point Reyes National Seashore, the National Park Service investigated.  The gray fox was sent to their lab in Colorado and found to have unexplained hemorrhaging in the brain and lungs with no signs of trauma.  These are classic signs of anticoagulant rodenticide poisoning, so the liver was sent to be analyzed by the California Animal Health and Food Safety Laboratory in Davis. The liver contained a toxic combination of three different second generation anticoagulant rodenticides. These rodenticides – brodifacoum, bromadiolone, and difethialone – are only legally used by pest control professionals for rodent control in and around man-made structures. After eating these baits, rodents remain mobile for several days and can be eaten by wildlife or pets.

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Gray fox at the Point Reyes National Seashore.  Photo: NPS/Bernot

Members of the public cannot obtain these materials over the counter. Due to their harmful impacts to wildlife second generation anticoagulant rodenticides became restricted use materials in California in July 2014.

To protect local wildlife, the National Park Service and the California Department of Fish and Wildlife urge safer rodent control such as exclusion and trapping.  It is also recommended that residents ask any pest control company that they employ not to use these materials on their property.  The two agencies are teaming up to get the word out locally to prevent another incident near Point Reyes National Seashore.  However, this is not a unique situation.  Monitoring in California has found that the majority of predators and scavengers, such as foxes, bobcats, mountain lions, coyotes, and raptors,  are still being exposed to these materials.

Be a good neighbor to your local wildlife and help spread the word!

To learn more, please visit the CDFW webpage:

www.wildlife.ca.gov/Living-with-Wildlife/Rodenticides.

Captive-breeding colony of Amargosa voles continues its success

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Captively bred Amargosa voles. Photo credit: Nora Allen

Since 2014, CDFW-WIL has partnered with UC Davis in order to create and maintain a breeding colony of Amargosa voles essential to the recovery of the species.  If interested in learning more about the history and progress of the colony, please read more here.  Below is a video showing a few of the vole pups bred in captivity (Credit: Janet Foley).

Bear found dead in trespass marijuana grow

An Inyo county black bear found dead during our fall ungulate captures was likely poisoned by the pesticide carbofuran. The adult black bear was spotted by our helicopter crew lying dead across irrigation piping on a top of a knoll in the John Muir Wilderness. The situation was very odd so the helicopter crew collected to carcass and flew it into base camp for a post mortem examination by the Department wildlife veterinarian. While examining the dead bear some of the biologists noted that flies which contacted the bear’s saliva or diarrhea quickly died. In light of this finding, and the likely association with what appeared to be an illegal marijuana grow, we decided to shuttle the bear carcass straight to the California Animal Health and Food Safety (CAHFS) laboratory for a full post mortem examination including necropsy and toxicological testing.

The initial necropsy findings were unremarkable. Toxicological testing detected carbofuran in stomach contents. No other carbamate or organophosphate pesticides were detected. In addition to the toxicology findings, microscopic examinations of tissues showed non-suppurative inflammation in the brain. Inflammation of this sort is typically caused by a virus, but rabies and canine distemper viruses were not detected. A cause for the encephalitis has not yet been determined and we are screening tissues for a possible gammaherpes virus that has been identified in other bears with similar brain inflammation. The significance of this finding in this bear is unknown, but was unlikely to be a contributing factor in the bear’s death. The detection of carbofuran and no other pesticides in conjunction with a decreased brain cholinesterase activity, a hallmark of organophosphate or carbamate pesticide intoxication, strongly supports carbofuran intoxication as the cause of death.

Carbofuran causes death by extreme over stimulation of the nervous system, which often ultimately leads to respiratory failure. The extreme toxicity of this material is illustrated by the fact that about approximately 64 rats or 12,000 sparrows would be killed by a single aspirin-sized tablet of the technical material. Carbofuran is one of the most toxic carbamate pesticides ever produced, and as such all legal uses of carbofuran have been banned in the United States since 2009. That’s not to say that carbofuran itself is banned in the U.S., but that there are no legal uses of carbofuran in the U.S., so for all intents and purposes it has been banned. Prior to its discontinued use in the U.S., it was responsible for losses of thousands of birds, mammals, and fish. In recent years, there have been numerous cases of illegally imported carbofuran being found on trespass marijuana grows in California and  regular reports of associated wildlife losses. Some of these losses appear intentional. Carbofuran is still sold in other parts of the world, including some countries in Africa, Asia, and Latin America.

Prepared by Brandon Munk and Stella McMillin

Restoring habitat for the endangered Amargosa vole

In the Spring of 2016, CDFW (WIL and Region 6), UC Davis, BLM, USFWS, and many volunteers partnered to restore a key habitat patch utilized by the Amargosa vole. This habitat patch used to sustain the highest density of Amargosa voles in the world, but in 2010 it began to deteriorate due to changes in hydrology. The Amargosa vole team worked diligently to restore the water supply and reinvigorate vegetation growth at the marsh. Learn more about the Amargosa vole project.