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.

 

Photo Album of Large Mammal Captures – Spring 2014

This spring the Wildlife Investigations Laboratory assisted with 8 large mammal captures throughout California.  Wildlife capture projects are conducted to help biologists and veterinarians assess the health of these herds through biological sampling,  to place GPS collars on the animals to monitor movement and help study habitat use, and for translocating animals.  A total of 207 animals were captured including 132 deer, 21 pronghorn antelope, 36 elk and 18 bighorn sheep.  Below is a small collection of photos from our month in the field.

Large mammal project locations.  Spring 2014

Large mammal project locations. Spring 2014

Bandaging elk antlers to prevent injury

Bandaging elk antlers to prevent injury

Stabilizing elk for transport to trailer for relocation to another site.

Stabilizing elk for transport to trailer for relocation to another site. San Luis Refuge, US Fish and Wildlife Service, Merced County.

Pronghorn antelope

Pronghorn antelope, Modoc County. Photo by Richard Shinn.

Helicopter bringing deer into basecamp for health monitoring

Helicopter bringing deer into base camp for health monitoring, Inyo County

Translocation and release of Sierra Nevada bighorn to augment herd in Olancha

Translocation and release of Sierra Nevada bighorn to augment herd in Olancha, Inyo County.

Deer release after GPS collaring and health monitoring - Scott Valley, Siskiyou County.

Deer release after GPS collaring and health monitoring – Scott Valley, Siskiyou County. Photo by Eric Haney

The Tule Elk, A California Comeback Story

By Tom Batter, WIL Scientific Aid

The elk (Cervus canadensis) to this day remains an icon of what once was the unsettled, untamed American frontier.  There are four extant subspecies of elk in North America.  The Manitoban elk (C.c. manitobensis) is exclusive to Canada, but the other three subspecies can be found in California.  They are the Roosevelt elk (C.c. roosevelti) of the north coast rainforests, Rocky Mountain elk (C.c. nelsoni) of the northeastern counties, and the tule elk (C.c. nannodes) native to the Central Valley.

Elk distribution in California.

Elk distribution in California.  Photo courtesy of the DFW Elk Management Program.

Tule elk look similar to other elk in general size, shape, and color (albeit tules wear a slightly lighter brown).  Generally speaking, however, tule elk are overcome in maximum size by both Rocky Mountain elk and the great Roosevelt elk.  A good sized Roosevelt bull, the largest of the subspecies, can reach 1,000 pounds or more.  Tule elk are the smallest subspecies; in fact, at one time they were colloquially referred to as ‘dwarf elk’.  A large bull tule elk will tip the scales at about 700-800 pounds (hardly a ‘dwarf’ by any means), yet under ideal conditions they may grow larger.

The tule elk, the smallest of the elk subspecies, are best adapted to open country and semi-desert conditions among elk races (McCullough 1969).  Image source: CDFW

Tule elk once roamed the San Jaoquin Valley in ample numbers.  Early settlers found tule elk roaming the foothills of the Sierra Nevada west to the central Pacific coast and from the headstream of the Sacramento River south to the Tehachapi Mountains.  Much like the affliction of the American bison on the Great Plains, tule elk became a casualty of human settlement — particularly after the Gold Rush.

Unregulated market hunting, competition with livestock, and the introduction of nonnative plant species all contributed to the decline of tule elk.  What was more devastating, however, was the conversion of elk habitat to agricultural land.  When settlers turned to the plow not only did it remove food and cover resources for elk, it also brought about direct conflict between elk and farmers.  Increasing crop and fence damage fueled campaigns for the removal of the tule elk by those individuals whose livelihoods were affected.  By the time elk hunting was banned by the state legislature in 1873, it was unknown if any tule elk even remained.

Luckily tule elk did remain, thanks in part to the protection provided by California cattle baron Henry Miller.  In 1874 a pair of Tule elk was discovered on the Miller and Lux Ranch by a local game warden at Button Willow.  Miller set aside 600 acres (near present day Tule Elk State Natural Reserve) to give the elk a chance to rebound.  In 1914, the elk had experienced such growth in numbers that Miller requested the California Fish & Game Commission work to relocate the elk from his ranch.

In order to relieve Miller from elk damage to his property and crops (reportedly estimated at $5,000 per year), the U.S. Biological Survey attempted to relocate tule elk by lassoing them from horseback and transporting them to new areas, with little success.  From 1914 to 1934 the California Academy of Science took on tule elk relocation activities 21 times over the next several decades.  These attempts were not very successful either, although they did contribute to establishing the herds at Owens Valley, Cache Creek, and the Tupman Reserve.

From 1971 through 1989 complete species protection was granted to tule elk.  State and Federal laws were passed to prohibit hunting of tule elk until a population of at least 2,000 was reached.  Habitat improvement programs combined with an aggressive reintroduction campaign by the Department of Fish & Game and other state and federal agencies yielded a significant increase in California’s tule elk population.

Tule elk of the San Luis National Wildlife Refugre, circa 1970s.  Image source: BLM 3rd Annual Report to Congress on The Tule Elk.

Tule elk of the San Luis National Wildlife Refuge, cca the 1970s. Image source: BLM 3rd Annual Report to Congress on The Tule Elk, March 1, 1979.

Today there are twenty-two tule elk herds in the Golden State, totaling around 4,200 individuals with the population trending upward.

Due to competing land use practices, it is not easy for tule elk to freely move between sub-populations; this requires the Department of Fish & Wildlife to take action in order to meet statewide management objectives.To help maintain healthy herds, every so often CDFW is tasked with capturing and relocating healthy elk to different established

Dr. Annette Roug (right, kneeling) leads a team of biologists as they attempt to weigh a cow elk.  Photo credit: Joe and Nancy Rodrguez.

Dr. Annette Roug (front right) leads a team of biologists as they attempt to weigh a cow elk. Photo credit: Joe and Nancy Rodrguez.

herds.  Removing elk from one herd and placing them in another helps to simulate the natural movement of individuals between herds which increases genetic diversity, an important function of a healthy population.

The Wildlife Investigations Lab took part in one such capture and relocation effort at the end of March.  A total of 36 elk were captured via helicopter from the San Luis National Wildlife Refuge near Los Banos.  Once elk were netted from the helicopter, they were processed by capture teams.  Capture teams took measurements, collected hair, blood, and other biological data to assess the health of the herd before they moved on to their new locations.

The animals were successfully released to join their new herds.  A portion of the captured animals were also radio-collared to collect post-release movement information.

An elk sets eyes on joining its new herd.  Photo courtesy of Joe and Nancy Rodriguez.

An elk sets sights on joining its new herd. Photo courtesy of Joe and Nancy Rodriguez.

To read the CDFW news release from this successful capture, click here.

For more information on the CDFW Elk Program, click here.

Interested in more tule elk biology?  Click here.

 

 

Got Acorns?

If you have acorns in your area, be on the look out for band-tailed pigeons this winter. Band-tailed pigeons are California’s only native pigeon and this time of year, they will fly great distances to find acorns. Band-tailed pigeons are one of the rare bird species that will actually swallow acorns whole! Unfortunately, this behavior also makes them more susceptible to Trichomonosis, a disease caused by a single-celled microscopic protozoan parasite, Trichomonas gallinae.

Band-tailed pigeon. Photo by Krysta Rogers.

Adult band-tailed pigeon showing the characteristic white crescent and iridescent greenish-bronze patch of feathers on the hind neck and black band on the tail, for which the species was named. Photo by Krysta Rogers, 2013.

The parasite lives in the mouth and throat of infected birds, causing caseous (“cheese-like”) lesions to develop in the bird’s mouth or esophagus. As the lesions become larger, the pigeons can no longer swallow acorns, leading to weight loss and eventually death. The lesions also may cause the pigeon to suffocate, if they block the airway.

Band-tailed pigeons with Trichomonosis. Photos by Jeff Cann & Krysta Rogers.

Fig. 1: A band-tailed pigeon showing signs of infection with Trichomonosis.
Fig. 2: A dead band-tailed pigeon observed during a Trichomonosis die-off in 2012.
Fig. 3: Caseous lesions in the oral cavity of a band-tailed pigeon with Trichomonosis.
Photos by Jeff Cann (Fig. 1) & Krysta Rogers (Fig. 2 & 3).

While this disease can make pigeons sick any time of the year, large-scale die-offs only occur during the winter, in some years. The last series of mortality events were reported in 2012 in California, when up to 10,000 pigeons were estimated to have died between December and March. Recent research by CDFW suggests that these mortality events are more likely to occur in winters with low precipitation, similar to the conditions we’ve been experiencing so far this winter.

So, if you have acorns, be on the lookout for band-tailed pigeons and enjoy watching them comically hang from the branches as they try to reach an acorn. Hopefully, the pigeons will not experience any die-offs this winter. However, if you do happen to see 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.

Disease Surveillance Projects for Bighorn Sheep Completed in November

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Dr. Colleen Duncan from Colorado State University and Dr. Ben Gonzales from California Department of Fish and Wildlife collect biological samples from bighorn sheep for disease testing. (Photo courtesy of George Kerr, Society for the Conservation of Bighorn Sheep)

Early November 2013 was a busy time for Wildlife Investigations Laboratory staff.  Two important disease surveillance projects for bighorn sheep were conducted in the Mojave National Preserve in San Bernardino County and the Peninsular Ranges in San Diego and Imperial Counties.  A total of 91 sheep were captured, GPS collared for monitoring and biological samples taken so that a variety of disease tests could be done.  One significant test is for Mycoplasma ovipnenumonia, a bacteria that caused a bighorn die-off in the Mojave earlier this year. Scientists will use the laboratory results (still pending) to determine the cause of the disease and to document the number of animals involved and the geographic extent of the outbreak.

These projects could not have been conducted without the many partners involved including; The National Park Service, the Society for the Conservation of Bighorn Sheep, California Wild Sheep Foundation, United States Fish and Wildlife Service, Bureau of Land Management, Oregon State University and Colorado State University.

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Taking blood samples from bighorn sheep for use in disease testing. (Photo courtesy of George Kerr, Society for the Conservation of Bighorn Sheep)

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Inspecting bighorn for signs of respiratory distress. (Photo courtesy of George Kerr, Society for the Conservation of Bighorn Sheep)