Disease outbreak in Pine Siskins

The Wildlife Investigations Lab is monitoring pine siskins for mortality this winter. Pine siskins are a type of finch that are mostly brown in color with a bright yellow wing stripe that live in forested areas in California primarily during the winter. Pine siskins are an irruptive migrant, meaning they can be found in high densities in certain areas in some years, but often absent the next. This migration pattern is likely determined by food availability and weather conditions.

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Examination of a pine siskin that died of Salmonellosis.

This winter pine siskins have been reported in numerous areas throughout California with larger concentrations occurring along the central and south coasts as well as around Redding, in northern California. Increased mortality of pine siskins has been reported in several of these areas since mid-December. The Wildlife Investigations Lab has evaluated carcasses from these locations and determined the cause of mortality to be Salmonellosis, a disease caused by Salmonella bacteria.

Salmonellosis occurs periodically in some years in pine siskins throughout their range. Previous outbreaks in California occurred during the winter of 2012-13 and in 2015. Birds become infected with Salmonella bacteria when they ingest food, water, or come into contact with objects (e.g. bird feeders, perches, soil) contaminated with feces from infected birds. Sick birds often appear weak, have labored breathing, and may sit for prolonged periods of time with fluffed or ruffled feathers. Salmonellosis is highly fatal in pine siskin, with most birds dying within 24 hours after infection.

Salmonellosis in pine siskins is almost exclusively reported from locations with bird feeders that attract increased numbers of birds. Residents can help reduce transmission of the disease by removing artificial sources of food and water (bird baths and fountains) as these may increase disease transmission between individual pine siskin, and possibly other bird species, because they bring birds into closer contact than would occur normally.

Dead birds may be reported to the Wildlife Investigations Lab to help determine locations and numbers of birds affected during this Salmonellosis outbreak.

If sick birds are observed, please contact a local licensed wildlife rehabilitation center for advice.

Another Turkey Vulture Poisoned by Euthanasia Drugs

CDFW Wildlife Investigations Laboratory has confirmed that another turkey vulture has been poisoned by the veterinary euthanasia drug pentobarbital near Inverness, in Marin County (see map below). The massive bird with its six-foot wingspan has recovered and will be released near Inverness (Marin County) on Tuesday, August 11 at 2 p.m. Reporters who would like to see this vulture return to the wild should call 415-806-8637 Tuesday for the exact location.

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CDFW confirmed pentobarbital exposure in six turkey vultures in San Rafael in 2014, but the source of the exposure remains unknown. Those birds were taken to the wildlife hospital operated by the nonprofit WildCare in San Rafael. WildCare is a CDFW-approved wildlife rehabilitator.

Wildlife officials are concerned that the July 2015 admission of an additional pentobarbital-poisoned vulture to WildCare indicates that more wildlife are at risk.

Pentobarbital is a drug used by veterinarians to euthanize companion animals, livestock and horses. If the remains of animals euthanized with pentobarbital are not properly disposed of after death, scavenging wildlife – such as turkey vultures and eagles – can be poisoned. Veterinarians and animal owners are responsible for disposing of animal remains properly by legal methods such as cremation or deep burial.

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Turkey vultures are protected by the federal Migratory Bird Treaty Act and California Fish and Game Code. Euthanized remains that are not disposed-of properly are a danger to all scavenging wildlife.

CDFW asks members of the veterinary and livestock communities to share this information with colleagues, to prevent additional poisoning. WildCare also asks the public to pay attention to grounded turkey vultures and other raptors and scavengers.

Pentobarbital-poisoned birds appear to be dead. They have no reflex response and breathing can barely be detected. The birds appear intact, without wounds or obvious trauma. Anyone finding a comatose vulture should call WildCare’s 24-hour Hotline at (415) 456-SAVE (7283) immediately.  Anyone with information about possible sources of pentobarbital-contaminated animals should contact the California Department of Fish and Wildlife at (916) 358-2954.

Toxicological analysis was performed by the California Animal Health and Food Safety Laboratory in Davis.

BOLO for BTPI

Be on the look out for band-tailed pigeons! Reports this month indicate band-tailed pigeons, California’s only native pigeon, are utilizing areas where they haven’t been in years. Observers have reported flocks of 50 to 100 birds in locations where pigeons haven’t been seen in at least 15 to 20 years. These seemingly erratic movements are directly tied to available food resources. During the winter, band-tailed pigeons feed primarily on acorns. They are one of the few species that actually swallow acorns whole!

Adult band-tailed pigeon showing the characteristic white crescent and iridescent greenish-bronze patch of feathers on the hindneck. Photo by Gary Kramer, 2008.

Adult band-tailed pigeon showing the characteristic white crescent and iridescent greenish-bronze patch of feathers on the hind-neck. Photo by Gary Kramer, 2008.

Acorns on a coast live oak (Quercus agrifolia) in Monterey County, a favoriate wintertime food of band-tailed pigeons. Photo by Krysta Rogers, 2011.

Acorns on a coast live oak (Quercus agrifolia), a favorite wintertime food of band-tailed pigeons. Photo by Krysta Rogers, 2011.

Acorn productivity fluctuates among oak species and between years. In some years, oaks may produce large quantities of acorns, in other years acorn production can be spotty. If acorns are not available, pigeons will rely on other food items such as madrone berries or pine nuts. However, the availability of all these plant foods are dependent upon weather conditions including temperature and the timing of rain, which leads to changeable food resources. Band-tailed pigeons must be adaptable to these variable conditions and seek out food resources across the landscape.

The observations of pigeons using “non-traditional” locations this winter may possibly be influenced by recent drought conditions. In Sacramento County, acorn productivity this season was very high and, in fact, bird watchers reported seeing flocks of band-tailed pigeons along the American River during fall migration. In contrast, a recent trip to the Los Padres National Forest in Monterey County, a location known to be especially reliable for both acorns and band-tailed pigeons, revealed neither acorns nor band-tailed pigeons this winter! Instead, pigeons were observed at lower elevations where abundant food was available.

Flock of band-tailed pigeons in oak tree in Santa Clara County. Photo by Krysta Rogers, 2014.

Flock of band-tailed pigeons in oak tree in Santa Clara County. Photo by Krysta Rogers, 2014.

Also likely related to drought, was the increased incidence of Trichomonosis in band-tailed pigeons this summer. Trichomonosis is a disease caused by a single-celled microscopic protozoan parasite, Trichomonas gallinae.  The parasite lives in the mouth and throat of infected birds, causing caseous (“cheese-like”) lesions to develop in the birds’ mouth or esophagus. The lesions eventually block the passage of food, causing the bird to become weak and emaciated. Infected birds die from starvation, or suffocation if the lesions block the airway.

An adult band-tailed pigeon showing signs of infection with Trichomonas parasites. Notice the drooped wings, ruffled feathers, and open-mouth breathing. Photo by Krysta Rogers, 2012.

An adult band-tailed pigeon showing signs of infection with Trichomonas parasites. Notice the drooped wings, ruffled feathers, and open-mouth breathing. Photo by Krysta Rogers, 2012.

Band-tailed pigeons are highly susceptible to infection with Trichomonas gallinae. Traditionally, large-scale die-offs occur during the winter months, in some years. However, this year the Wildlife Investigations Lab  received reports of increased mortality of band-tailed pigeons in several locations along the central California coast between May and August. Drought conditions likely resulted in increased contact between individual birds at limited food or watering sites, resulting in rapid spread of disease. This increased mortality of band-tailed pigeons is concerning because the band-tailed pigeon population has been declining for the past 40 years. Die-offs due to Trichomonosis can remove hundreds to thousands of pigeons from the population in a relatively short period of time.

This winter, be on the look out for band-tailed pigeons in your area. If you see pigeons, enjoy the spectacle, it may not occur at that location for another 20 years! And if you happen to observe pigeons that appear sick, such as showing signs of weakness, labored breathing, breathing with their bill open, drooling, reluctance to fly when approached, or are dead, you can help by reporting the mortality to the Wildlife Investigations Lab.

If you have any questions, or would like to report sick or dead band-tailed pigeons, contact Krysta Rogers at 916-358-1662.

Multi-agency Effort to Rescue Deer From Canal

A doe and her fawn found themselves in need of some assistance in getting out of a canal near the bridge on Hazel Avenue in Rancho Cordova on Monday, December 15.  Personnel from Sacramento Metropolitan Fire, Bureau of Reclamation, Kindred Spirits Fawn Rescue, California Fish and Wildlife North Central Region and the Wildlife Investigations Laboratory all contributed their expertise to ensure the best outcome for the deer.  The doe and fawn were safely captured and then released at Lake Natoma.  Below are pictures of the rescue.

Doe and fawn trapped in canal.

Doe and fawn trapped in canal.

 

Sacramento Metropolitan Fire rescuing doe from the canal

Sacramento Metropolitan Fire rescuing doe from the canal

California Department of Fish and Wildlife personnel blindfolding the doe to reduce  stress to the animal and hobbling the doe so she won't hurt herself or others

California Department of Fish and Wildlife personnel blindfolding the doe to reduce stress to the animal and hobbling her so she won’t hurt herself or others

 

Dr. Ben Gonzales from California Fish and Wildlife releasing the fawn after rescue.

Dr. Ben Gonzales from California Fish and Wildlife releasing the fawn after rescue.

 

Steps towards restoring an endangered species (Part II)

By Austin Roy (Scientific Aid)

Reintroductions, translocations, and augmentations are methods of restoring or increasing wildlife populations.  These actions require a lot of planning and are often expensive.  These methods involve removing animals from a source population and placing them in another location.  The goal of these efforts are usually to establish a sustainable population where one did not previously exist, provide new individuals to a site with a low population in hopes of increasing the population, and providing new or rare genes to a population that may need genetic rescue, among other reasons.

Healthy habitat at the recipient site that voles were translocated into.

Healthy habitat at the recipient site that voles were translocated into. Photo courtesy of Risa Pesapane

This summer our University of California, Davis and California Department of Fish & Wildlife (WIL) research team conducted a population augmentation for the endangered Amargosa vole (Microtus californicus scirpensis).  Our goal  was to supplement a very small population of voles in one marsh with new individuals and genes from a larger population in another marsh.

A "hard" release of a collared vole at the donor site.

A “hard” release of a collared vole at the source site.

We placed radio collars on 3 voles at the source site, 4 voles that we removed from the source site and relocated to the recipient site, and 3 individuals at the recipient site.  By collaring both relocated voles and resident voles at source site and the recipient site we could monitor how relocated animals utilized the new site and whether or not resident individuals were impacted by the presence of new individuals in their habitat.

Janet Foley (UC Davis Principal Investigator) conducting radio telemetry for collared Amargosa voles.

Janet Foley (UC Davis Co-Principal Investigator) uses and antenna and receiver to listen for the signals of radio- collared Amargosa voles. Photo courtesy of Risa Pesapane.

The data we collected will greatly benefit vole recovery and inform how we conduct future releases.

In addition to the augmentation efforts this summer we also continued to study the population cycles of voles and predators in the area.  These studies allow us to better understand how voles and predators use the area how the predators may be affecting vole populations.  We have also been studying the vegetation and water levels to better understand the needs of the Amargosa vole.  These efforts will help us better understand how to restore and improve vole habitat.

Stephanie Castle, Risa Pesapane, and Amanda Poulsen (UC Davis Graduate Students) conducting a point count for Amargosa vole predators.

Stephanie Castle, Risa Pesapane, and Amanda Poulsen (UC Davis Graduate Students) conduct a point count for Amargosa vole predators.

The research this summer would not have been possible without the support from our partners at the U.S. Bureau of Land Management, U.S. Fish & Wildlife Service, CA Department of Fish & Wildlife (Region 6), Integral Ecology Research Center, U.S. Geological Survey, Shoshone Village, Inyo County Roads Department, and the Amargosa Conservancy.